Symposium Organizers
Michael Rein, Massachusetts Institute of Technology
Max Shtein, University of Michigan-Ann Arbor
Guangming Tao, University of Central Florida
SM2.1: Advances in Fibers and Textiles I
Session Chairs
Tuesday PM, April 18, 2017
PCC North, 100 Level, Room 122 A
11:30 AM - *SM2.1.01
Realizing a Moore’s Law for Fibers
Yoel Fink 1
1 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractFibers and fabrics are among the earliest forms of human expression, and yet they haven’t progressed much from a functional standpoint over the course of history. Recently, a new family of fibers composed of conductors, semiconductors and insulators has emerged. These fibers can achieve device attributes, yet are fabricated using scalable preform-based fiber-processing methods, yielding kilometers of functional fiber devices. Moreover, it is expected that the functions of fibers will increase dramatically over the next years creating a fiber equivalent of the “Moore’s law”. In this talk I will describe the underlying evidence for this “law” and discuss paths to achieving system level behavior on the fabric level. I will also outline progress to date in establishing AFFOA, a DoD-backed national center; its mission is to enable a domestic manufacturing-based revolution by transforming traditional fibers, yarns, and fabrics into highly sophisticated, integrated and networked devices and systems that will see, hear, sense and communicate, store and convert energy, and change color.
12:00 PM - SM2.1.02
3D Printing-Enabled Digitally Designed Multifunctional Polymeric Particle Fabrication
Joshua Kaufman 1 , Christopher Bow 1 , Felix Tan 1 , Ayman Abouraddy 1
1 , University of Central Florida, Orlando, Florida, United States
Show AbstractAdditive manufacturing or 3D printing is an emerging technology that allows for rapid prototyping starting from raw materials. The objects produced are macroscale and limited in feature size by the resolution of the printer, or approximately 20-200 microns with current technology. Producing nanodroplets or nanoscale features directly using 3D printing is currently impossible; and while producing micro-scale droplets may be achievable in principle, it would be inefficient because of slow printing speeds and the necessity of printing one droplet at a time. Thermal fiber drawing (TFD), on the other hand, can produce fibers with feature sizes down to 5 nm in the transverse dimension [1]. However, even simply structured preforms require specialized equipment (vacuum furnaces, fume hoods, extrusion machines, etc) to make solid preforms, and renders elaborately structured cores a difficult task. Furthermore, the materials processing typically starts from granules or thin films into cylindrical rods which must then be machined and combined together to produce the desired structure. 3D printing bypasses this complexity, and obviates the need for specialized skills involved with the previous processes. All that is required is a CAD model and a technician to initiate the print. Recently, a new method for fabricating structured, multi-material, multi-functional micro- and nano-particles has been developed that utilizes fluid instabilities in multi-material fibers [2]. Here we propose thermal fiber drawing as a way to bridge the gap between current 3D printing capabilities and nanotechnology, with 3D printing complementing the difficulties of preform construction.
Our 3D printing system is a home-built machine put together from a kit purchased online. We begin by producing polylactic acid (PLA) particles from a preform whose core was printed using commercially available 3D printer filament and whose cladding was an extruded hollowed out cylinder from commercially available polystyrene (PS). The fiber drawn from this preform is then heated to induce the Plateau-Rayleigh capillary instability (PRI), forming spherical particles with a diameter approximately twice the diameter of the initially intact core. We then repeat this process with filaments that we have fabricated in-house from materials that are not commercially available as 3D printing filament, such as cyclic olefin polymer (COP). We demonstrate the strengths of 3D printing the preforms by producing fluorescent COP filaments and printing complex core geometries, such as three-petal, star-shaped, single fluorescent color yin-yang, two-color fluorescent yin-yang, and multi-functional fluorescent-magnetic Janus. These fiber core geometries are then conferred to the produced microparticles, which we confirm using confocal scanning laser fluorescence microscopy.
References
[1] Kaufman, J. J., et. al. Nano Lett. 11, 4768-4773 (2011).
[2] Kaufman, J. J., et. al. Nature 487, 463-467 (2012).
12:15 PM - SM2.1.03
Thermal Drawing of Electronic and Photonic Fiber Devices
Michael Rein 1 , Yoel Fink 1
1 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractThermal drawing of fibers is a powerful technique that allows to achieve a wide range of active and passive fiber devices, some of which were demonstrated by our team. Alas, this method has its limitations. The set of materials we are able to draw is limited by their thermomechanical properties. Traditionally, in order to achieve a successful draw, all the materials have to co-draw at the same temperature, requiring the materials to have low viscosities at the draw temperature and to be chemically compatible with each other. As we lower the draw temperature, we limit the set of materials we are able to integrate into the fiber. Naively we might aim towards higher drawing temperature, but unfortunately, higher draw temperatures often lead to high rates of diffusion and undesired chemical reactions, which often prevent us from achieving the desired fiber structure and functionality. Many, if not most of the common electronic devices are comprised of a large set of materials, where the central components are made of crystalline semiconductors, high melting temperature alloys, thin films or thermoset polymers, which are not readily drawable into a fiber. For example, light emitting diodes are comprised of several crucial components - at least two doped direct bandgap semiconductors and metallization for current supply. Integrating these components during the fiber draw is a challenging feat, mostly due to diffusion problems during high temperature draw.
Here, we demonstrate an alternative strategy for integrating devices into fibers. Rather than addressing the challenges described above, we directly integrate functional devices (ex: LEDs, detectors, transistors) into the preform and draw these devices into fibers without deforming them in the process. Miniaturized devices such as LEDs and photodiodes (cross sections of order 100 microns) can been created with conventional microelectronics techniques. Currently, these devices are readily commercially available, are cheap and have been optimized for high efficiency performances. We integrate these devices into fibers, which could be packaged in high density and integrated with conductive buses, during thermal draw. This approach enables to combine the benefits of several technologies – high efficiency devices integrated into kilometer long fibers, which could be weaved into highly functional fabrics.
Endowing fibers with active devices will potentially establish a new generation of multifunctional fibers, with highly desired electronic properties. For example, light emitting devices could be integrated to enable covert, optical signal transmission from the soldier uniform to the external world, different wavelength emitting devices could be used simultaneously, high bandwidth photodetectors could be co-embedded to allow two-way transmission and reception of communication between the wearer of the fabric and the command control.
12:30 PM - *SM2.1.04
Tailoring Surface and Rheological Properties of Fiber Materials: Novel Scientific Insight and Opportunities for Multi-Material Fibers
Fabien Sorin 1 , Dang Tung Nguyen 1 , Wei Yan 1 , Alexis Page 1 , Yunpeng Qu 1 , Marco Volpi 1 , Shahrzad Shadman 1 , Tapajyoti Das Gupta 1 , Federica Sordo 1
1 Institute of Materials, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne Switzerland
Show AbstractThe recent development of fiber processing technologies is enabling the fabrication of fiber structures with increasingly complex functionalities. In particular, the thermal drawing process used to fabricate optical fibers has experienced a series of breakthroughs that have expanded the range of cross-sectional architectures and materials that can be integrated in fibers. It has been recognized in recent studies that interfacial tension and viscosity play a crucial role in the type of materials, structure and feature sizes that can be achieved in thermally drawn fibers. While this has advanced our understanding of, and opened new prospects for, the thermal drawing process, a large number of scientific questions and opportunities associated with the tailoring of interfacial tension and the rheological properties of materials remain unexplored. In this talk, we will present our recent work to deepen our understanding of the materials science behind thermal drawing patterning to engineering interfacial tension and viscosity. We will first show how we can tailor the interfacial tension of polymers to realize fibers and micro-channels with sub-micrometer surface textures. We will then demonstrate how modifying the surface energy of semiconducting materials in solution can enable the fabrication of single-crystal nanowire-based optoelectronic fibers with unprecedented performance. Finally, we will revisit the criteria traditionally associated with the compatibility of materials with thermal drawing, by having a deeper look at not only the viscosity but also the relative values of the shear storage and loss moduli. We will exploit this finding to show that contrary to traditional elastomers, some polymers can exhibit rheological attributes compatible with thermal drawing at high temperature, while behaving like elastic materials at room temperature. This opens novel opportunities for fiber-based stretchable optics and electronics at the scalability traditionally associated with optical fibers.
SM2.2: Energy Storage and Harvesting in Fibers and Textiles
Session Chairs
Alexander Gumennik
Max Shtein
Tuesday PM, April 18, 2017
PCC North, 100 Level, Room 122 A
2:30 PM - *SM2.2.01
Micro and Nanostructured Fibers for Smart Surfaces, Triboelectric/Piezoelectric Energy Harvesting and Sensing
Mehmet Bayindir 1
1 UNAM, Bilkent University, Ankara Turkey
Show AbstractI will review our recent works on (1) hierarchically structured fibers for smart and functional surfaces, (2) triboelectric energy harvesting and biochemical sensing inside poly(vinylidene fluoride) hollow fibers, (3) self-organized nanostructured morphologies in kilometer-long polymer fibers and their applications including structural coloration, (4) surface textured polymer fibers for microfluidics, and (5) piezoelectric polymer nanoribbons for artificial hand and electro cardiac devices.
3:00 PM - SM2.2.02
Machine-Washable Smart Fabric for Energy Harvesting and Human Respiratory Monitoring
Zhizhen Zhao 1 , Casey Yan 2 , Zijian Zheng 2 , Youfan Hu 1
1 , Peking University, Beijing China, 2 , The Hong Kong Polytechnic University, Hong Kong China
Show AbstractTextile-based electronic devices have attracted surging interests due to the huge demand in wearable technologies in recent years. Being an essential part of the wearable system, textile-based energy harvesting devices have demonstrated the potential ability to meet the demand for lightweight, portable, flexible and green energy supply in wearable devices. In particular, textile triboelectric nanogenerators (t-TENGs) have exhibited remarkable superiority in mechanical energy harvesting and self-powered sensing because of their ease of fabrication. Here we demonstrates for the first time the scalable approach for machine-washable t-TENG by directly weaving copper-coated polyethylene terephthalate (Cu-PET) yarns and polyimide-coated Cu-PET (PI-Cu-PET) yarns on an industrial sample weaving loom. The new t-TENG takes full advantages of the woven structure itself: upon even very subtle deformation, the contact area of the crisscross intersections of the weft and warp yarns changes, which lead to effective generation of triboelectric charges. It allows the effective energy collection and monitoring for subtle human body motions. The fabric can provide an output power density around 33 mW / m2 at current stage. A wearable respiratory monitor integrated with the new t-TENG is demonstrated for human respiratory rate and depth recording for the first time. More importantly, the as-made unpackaged fabric can withstand the machine-wash tests, which are carried out in a commercial laundering machine including washing, rinsing and spinning for 40 minutes. It shows remarkable washing durability.
The textile industry compatibility, the proven machine wash ability, and the sensitivity to subtle human body motions make the fabric obtained here a very promising candidate for wearable technology with excellent scalability, and can be further applied in the field of sports, healthcare and many others.
3:15 PM - SM2.2.03
Flexible and Wearable Energy Storage Fibers and Textiles
Ye Zhang 1 , Huisheng Peng 1
1 , Fudan University, Shanghai China
Show AbstractFlexible, portable and wearable electronic devices such as smart clothes are emerging in the mainstream and represent promising directions for future lifestyles. The rapid development strongly demands indispensable power systems that can be miniaturized, flexible, and adaptable. Lithium ion batteries have been used as one of the most ubiquitous types of power supplies. However, conventional lithium ion batteries, including both rigid bulk and flexible film, cannot satisfy the above requirements. These batteries have limited flexibility and cannot effectively adhere to soft substrates such as our bodies under deformation. Besides, they are not breathable, which is also a major consideration for wearable electronics. A revolution in lithium ion battery structure is necessary to ultimately solve these problems.
Herein, we have developed a new family of fiber-shaped lithium ion batteries and lithium air batteries with high performance based on carbon nanotube hybrid fiber electrodes. The unique fiber architecture allows batteries to be deformable in all dimensions and bear various deformations such as bending, tying and twisting and stretching. They are scaled up and further woven into breathable, light-weight, flexible, stretchable and shape-memory textiles to effectively meet the requirements of the modern electronics such as wearable products. The obtained flexible energy textiles with an area of 0.1 m2 can power an iPhone for 10 hours.
3:30 PM - *SM2.2.04
Fiber-Shaped Energy Harvesting and Storage Devices
Huisheng Peng 1
1 , Fudan University, Shanghai China
Show AbstractIt is critically important to develop miniature energy harvesting and storage devices in modern electronics, e.g., for portable and foldable electronic facilities. Here novel miniature fiber-shaped energy conversion and storage devices as well as their integrated devices are carefully discussed with unique and promising advantages such as lightweight and weaveable compared with the conventional planar architecture.1-5 For the fiber-shaped energy conversion devices, dye-sensitized solar cells, perovskite solar cells and polymer solar cells are covered. For the fiber-shaped energy storage devices, electrochemical capacitors, lithium ion batteries, lithium sulfur batteries, lithium air batteries and zinc air batteries are carefully investigated. The main efforts will be made to highlight the recent advancement in the electrode material, device structure and property extension.
4:30 PM - *SM2.2.05
Advanced Functional Fibers for Energy Harvesting and Bio-Sensing
Lei Wei 1
1 School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore Singapore
Show AbstractAdvanced functional fibers offer a novel degree of freedom to engage applications spanning smart and flexible electronics, nanorobotics, next generation of sensors and transducers, biomedical diagnosis/therapy, and prosthetics.
We firstly demonstrate flexible nanocomposite film enabled fiber devices based on a conducting polymer PEDOT:PSS, a plastic reinforcer PVA and inorganic Bi0.5Sb1.5Te3 nanocrystals with various contents using drop casting approach. They are mechanically tough, yet very flexible with the tensile strength of 79.3 MPa and the fracture strain of 32.4%, which is sufficient to meet the required mechanical properties of textile manufacturing and body movements for flexible thermoelectric devices, thus providing a substantial impact on future developments of flexible/wearable energy generation devices.
Secondly, we demonstrate an optical fiber based surface plasmon resonance (SPR) biosensor seamlessly integrated with the graphene-on-gold hybrid structure. As a result, introducing a graphene layer to conventional thin gold film excited SPR effectively boosts the sensing performance. More meaningfully, the graphene not only strengthens the excited SPP, but also acts as an excellent replacement of surface functionalization to stably immobilize biomolecules via π-stacking interaction. We believe this study will stimulate new fundamental scientific research on hybrid SPR sensing mechanism.
5:00 PM - *SM2.2.06
Modeling of Textile Mechanical Energy Generators Based on Triboelectric and Piezoelectric Effects
Xiaoming Tao 1 , Bao Yang 1 , Song Chen 1
1 Nanotechnology Centre for Functional and Intelligent Textiles and Apparel, Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Kowloon Hong Kong
Show AbstractHarvesting mechanical energy from human activities by triboelectric and piezoelectric nanogenerators (TENGs and PNGs) or their hybrids is an effective approach for sustainable, maintenance-free, and green power source for wireless, portable and wearable electronics 1-3. The textile-based generators that utilize the triboelectric or piezoelectric effects are light weight, long-lasting, well suited for the intended applications 4. However, the power output from the generators is of μW, several orders of magnitude away for most real applications of microelectronic systems. Ample efforts have been made around the world to develop such technologies, mostly experimentally. At present, we do not have a mean to predict the best performance from the generators and the ways to achieve their maximum performance. We need to answer a few scientific queries: (1) What kinds of generator structures have the best performance? (2) What are the theoretical limits of the output power and energy conversion efficiency by a given generator and working conditions? (3) How do we get there?
This paper presents a theoretical framework for modeling such nanogenerators based on the principles of charge generation, charge conservation and zero loop-voltage. Under the framework, two cases are demonstrated. The first one is a contact-mode TENG made from fabrics 5. Explicit expressions for the output current, voltage and power are presented for the TENGs with an external load of resistance or capacitor. Experimental verification is conducted by using a contact-mode TENG made from fabric electrodes and polydimethylsiloxane/graphene oxide composite as the dielectric layer. Excellent agreements are demonstrated between the theoretical and experimental results, without any adjustable parameters. The effects of the moving speed on output voltage, current and power are illustrated.
The second case is hybrid textile nanogenerators comprising cascaded piezoelectric and triboelectric units. A theoretical analysis of the contact-mode hybrid generator describes the relationships among transfer charges, voltage, current and average output power in terms of materials properties, device structural parameters, operational conditions 6. The results would provide a powerful tool for synthesis and selection of materials, design and optimization of the configuration and operation of such kind of hybrid generators as well as determination of the value of external capacitor.
Acknowledgement
The work has been partially supported by Research Grants Council, Hong Kong (No. 525113, 15215214,1521016).
References
Wang ZL, Lin L, Chen J, Niu S, Zi Y. Triboelectric Nanogenerators, Springer Intern Pub, 2016.
Tao XM, 2015. Handbook of Smart Textiles, Springer Intern Pub. 2015.
Zeng W, Shu L, Li Q, Chen S, Wang F, Tao XM, 2014, Adv Mater. 26(31):5310-5336, DOI: 10.1002/adma.201400633.
Zeng W, Tao XM, Chen S, Shang SM, Chan Wong LW, Choy SH, 2013. Energy Environ Sci, 6 (9), 2631 – 2638.
Yang B, Zeng W, Peng ZH, Liu SR, Chen K, Tao XM, 2016.Adv Energy Mater, 6(16) DOI: 10.1002.
Chen S, Tao XM, Zeng W, Yang B, Shang SM, 2016. Adv Energy Mater, accepted.
5:30 PM - SM2.2.07
Machine Washable PEDOT:PSS Dyed Silk Yarns for Wearable Thermoelectrics
Desalegn Mengistie 1 , Jason Ryan 1 , Roger Gabrielsson 2 , Anja Lund 1 , Christian Muller 1
1 , Chalmers University of Technology, Gothenburg Sweden, 2 IFM, Linköping University, Linköping Sweden
Show AbstractWearable thermoelectrics which have several applications from powering wearable electronics to medical implantables need to be flexible to easily integrate on textiles. We demonstrate conducting silk yarns, which have excellent mechanical properties, by dyeing with PEDOT:PSS by facile method which is easily scalable to dye fabrics. Optical and scanning electron microscopy showed that the dyeing was uniform and each fiber in the yarn is dyed with few hundred nm of PEDOT:PSS. The dyed yarns showed Seebeck coefficient of ~17 µV/K and electrical conductivity of ~17 S/cm (taking the whole bulk yarn). The tensile stress decreased only slightly while the elongation at break increased slightly from 11% to 13.7% after dyeing. The dyed yarns were quite flexible with almost no resistance change after 1000 bending cycles with radius of 2.25 mm. We demonstrated both in-plane and out-of-plane thermocouples on thick fabrics. The stability of dyed yarns was also assessed by keeping them in the ambient air for months and by washing in water and dry cleaning solvent. Other applications of the conducting silk will also be discussed.
5:45 PM - SM2.2.08
Radiative Human Body Cooling by Nanoporous Polyethylene Textile
Po-Chun Hsu 1 , Alex Song 1 , Peter Catrysse 1 , Chong Liu 1 , Yucan Peng 1 , Jin Xie 1 , Shanhui Fan 1 , Yi Cui 1
1 , Stanford University, Stanford, California, United States
Show AbstractThermal management through personal heating and cooling is a strategy by which to expand indoor temperature setpoint range for large energy saving.We show that nanoporous polyethylene (nanoPE) is transparent to mid-infrared human body radiation but opaque to visible light because of the pore size distribution (50 to 1000 nanometers).We processed the material to develop a textile that promotes effective radiative cooling while still having sufficient air permeability, water-wicking rate, and mechanical strength for wearability. We developed a device to simulate skin temperature that shows temperatures 2.7° and 2.0°C lower when covered with nanoPE cloth and with processed nanoPE cloth, respectively, than when covered with cotton.Our processed nanoPE is an effective and scalable textile for personal thermal management.
Symposium Organizers
Michael Rein, Massachusetts Institute of Technology
Max Shtein, University of Michigan-Ann Arbor
Guangming Tao, University of Central Florida
SM2.3: Advances in Fibers and Textiles II
Session Chairs
Michael Rein
Sasha Stolyarov
Wednesday AM, April 19, 2017
PCC North, 100 Level, Room 122 A
9:00 AM - *SM2.3.01
The Molten Core Fabrication of Novel Optical and Optoelectronic Fibers
John Ballato 1
1 , Clemson University, Anderson, South Carolina, United States
Show AbstractThe global ubiquity and near-instantaneous nature of information today is owed to the remarkable successes of glass optical fibers. As new applications have emerged where optical fibers are again the enabling technology, practitioners have largely leveraged the manufacturing methods employed in telecommunications. While such processes are mature and highly scaled, they permit only a limited range of glass compositions that do not necessarily meet the performance demands of these new applications. This talk will highlight advances in silica-based optical fibers fabricated using the innovative molten core approach which vastly expands the range of compositions that can be achieved. Particular attention will be paid to novel optical fibers that gain their performance from not-previously-employed core/clad interactions and exhibit properties of great value to next generation laser, photovoltaic, and imaging systems.
9:30 AM - SM2.3.02
Intermediate-Tg-Glasses for Hybrid/Composite Fiber Devices—Recent Advances and New Prospects
Sylvain Danto 1 2 , Clement Strutynski 1 3 , Frederic Desevedavy 3 , Yannick Petit 1 , Jean-Charles Desmoulin 1 , Alain Abou-Khalil 4 , Marc Dussauze 5 , Jean-Charles Jules 3 , Gregory Gadret 3 , Frederic Smektala 3 , Lionel Canioni 4 , Thierry Cardinal 1
1 , Institut de Chimie de la Matière Condensée de Bordeaux, Pessac France, 2 , University of Bordeaux, Bordeaux France, 3 Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNR, University of Bourgogne Franche-Comté, Dijon France, 4 , Centre Lasers Intenses et Applications, Bordeaux France, 5 , Institut des Sciences Moléculaires, Bordeaux France
Show AbstractResearch on multimaterial multifunctional fibers flourished in the recent years, proposing an ever growing set of materials suitable for co-drawing as well as of fiber functionalities. So far however, advances relied mostly on two glass families (i) on high-Tg silica-based materials (Tg > 1000 °C), that were extensively studied for photonics or for photonics/electronics hybrid applications, such choice being dictated by the technological interest of silica, and (ii) on low-Tg chalcogenide glasses (Tg < 250 °C) that were deployed for integration in multimaterial glass/polymer/metal fibers. Glass selection was then strongly driven by the availability of high-Tg polymers compatible with co-drawing.
Here we propose to explore the “glass territory”; specifically, we propose to question the feasibility of fabricating multimaterial fibers on the basis of glasses with intermediate glass transition temperatures. The presentation focuses on two types of glasses: the phosphate glasses (Tg ~350-450°C) and the tellurite glasses (Tg ~250-300°C). Firstly, we explore hybrid fibers, that is to say fibers with active functions being embedded within the glass matrix, with a focus on phosphate-based fibers. Tailored Ag-containing zinc-phosphate glasses possess excellent thermo-viscous ability, optical properties, and they have proven to form a favorable matrix for the direct Laser writing of photo-luminescent patterns. We report on the drawing of photosensitive, photo-writable Ag-containing glass ribbon fibers. We demonstrate that luminescence properties of the native glass are preserved after shaping. Furthermore, we establish that the unique fiber's flat geometry allows for the direct, accurate Laser writing of complex luminescent silver clusters patterns and functionalities within the glass matrix. Secondly we explore composite fibers (here fibers are made from a stack of materials with disparate electrical/optical/thermal properties), with a focus on tellurite-based materials. Tellurite glasses possess excellent thermo-viscous ability and linear/non-linear optical properties. Bringing together the merits of these materials with fiber optic technology, we describe the fabrication of core-clad dual-electrodes composite fibers. These novel devices are thermally scaled-down in a homothetic fashion from a macroscopic preform to produce tens-of-meters of continuous structure. We demonstrate the electrical continuity of the electrodes over meters of fiber. Furthermore, we establish that the fiber geometry allows for the super-continuum generation. Connection issues and electro-optic coupling will be discussed.
Great challenges lie ahead when it comes to mastering the implementation of intermediate-Tg oxide glasses within multimaterial fibers, but great opportunities lie ahead too, as it would give access to a whole new range of intrinsic materials properties, and hence of functionalities, in linear/nonlinear optics, photonics, electro-optics or sensing.
9:45 AM - SM2.3.03
Thermally Drawn, Electrically Conductive Glass Fibers
Guangming Tao 1 , Felix Tan 1 , Shi Chen 1 , Romain Gaume 1 , Ayman Abouraddy 1
1 CREOL, The College of Optics & Photonics, University of Central Florida, Orlando, Florida, United States
Show AbstractMuch work has been done in the field of multimaterial fiber drawing and devices derived from such fibers [1]. Certain advantages are afforded by these multimaterial systems—for instance, each material can provide a different functionality to support the overall performance of the device. Moreover, drawing from a preform permits structuring at a centimeter scale. As such, complex architectures and features can be imparted on to the final fiber geometry that would otherwise be extremely difficult or impossible to achieve from a “bottom-up” fabrication approach.
An example of a multimaterial fiber device was previously reported [2]. The device is comprised of three materials—a metal, semiconductor, and insulator. Thermal drawing of such material systems requires that the materials exhibit melt viscosities, softening, and/or melting temperatures that overlap. However, these criteria impose a significant burden in the materials selection. In the previous work, two of the three materials were amorphous: an engineering thermoplastic resin such as PEI or PES (insulator), and a chalcogenide glass (semiconductor). The metal constitutes the only crystalline phase with a sharp melting transition from solid to low-viscosity-liquid. This is an important feature—if two of the three phases are crystalline, they will both transition to low viscosity, thereby compromising the integrity of the fiber architecture. However, the best semiconductor materials are also crystalline, presenting a limitation to the overall device performance.
To improve the overall performance and overcome limitations of the earlier designs, we present here a fiber system containing an electrically conductive, amorphous composite phase. The conductivity in the composite is provided by the addition of carbon nanofibers (CNFs) into a glass matrix that has been carbonized with a small concentration of polyethylene glycol (PEG). The carbonized PEG boosts the background conductivity of the glass such that conduction is permitted even when the CNFs are disjoint—i.e. when a continuous CNF network is not present throughout the composite volume [3]. This new composite glass replaces the metal in the previous work as the conductor—an amorphous phase in place of the crystalline phase. The composite can then be drawn with a virgin glass (insulator) to produce a multimaterial system with an axially continuous, embedded conductive phase. In order to facilitate the drawing, a fiber draw tower was custom-designed and constructed. We also present results incorporating a crystalline semiconductor as an initial step towards fabricating a complete optoelectronic device in fiber form.
[1] A. F. Abouraddy, et al. "Towards Multimaterial Multifunctional Fibers that See, Hear, Sense and Communicate." Nature Mater. 6 336-347 (2007)
[2] Bayindir, M. et al. “Integrated fibres for self-monitored optical transport.” Nature Mater. 4, 820–825 (2005)
[3] G. Tao, et al. To be submitted. (2016)
10:00 AM - *SM2.3.04
High Pressure Chemical Vapor Deposition of Optoelectronic Fiber Material
John Badding 1 2 3 , Pier Sazio 5 , Xiaoyu Ji 2 4 , Stephen Aro 1 4 , Rongrui He 1 4 , Justin Sparks 1 4 , Subhasis Chaudhuri 1 4 , Todd Day 1 4 , Anna Peacock 5 , Noel Healy 5 , Venkat Goplan 2 4
1 Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania, United States, 2 Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania, United States, 3 Department of Physics, Pennsylvania State University, University Park, Pennsylvania, United States, 5 Optoelectronics Research Center, University of Southampton, Southampton United Kingdom, 4 Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania, United States
Show AbstractHigh Pressure Chemical Vapor Deposition (HPCVD) allows for the deposition of structured elemental and compound semiconductors into the empty pores of microstructured optical fibers.1,2 It can fill these pores completely void-free with unary semiconductors over long lengths to form near atomically smooth (~0.1 nm RMS surface roughness), very geometrically perfect (round, uniform cross sectional diameter) fiber cores of hydrogenated amorphous, amorphous, or crystalline silicon or germanium.
Laser heating elemental semiconductor fiber cores3 has allowed for single crystal small core (1-2 μm) silicon and germanium4 optical fibers with optical losses as low as 0.5 dB/cm. Small cores are important for single mode or near single mode optical guidance. These elemental semiconductor fiber cores can serve as the building blocks for optoelectronic devices, such as meter-long pin junctions5 and GHz bandwidth in-fiber detectors.6 Seamless coupling of semiconductor optoelectronic and photonic devices with existing fiber infrastructure thus becomes possible, facilitating all-fiber technological approaches. There has been much interest in the possibility of woven solar fabrics incorporating efficient silicon junctions.
HPCVD was later extended to demonstrate the first small core crystalline compound semiconductor ZnSe optical fibers, which are capable of guiding near/mid infrared optical powers 2 to 3 orders of magnitude higher than conventional chalcogenide glass fibers. These ZnSe fibers can be doped with chromium to allow for continuous wave tunable infrared fiber lasers. Synthesis of carbon nanothreads inside optical fiber pores represents a promising direction for realizing fibers of unprecedented mechanical strength to weight ratio and novel properties associated with mixed sp2/sp3 carbon hybridization.7
1 Sparks, J.R., Sazio, P.J.A., Gopalan, V., & Badding, J.V., Templated Chemically Deposited Semiconductor Optical Fiber Materials. Annual Review of Materials Research, Vol 43 43, 527-557 (2013).
2 Sazio, P.J.A., Amezcua-Correa, A., Finlayson, C.E., Hayes, J.R., Scheidemantel, T.J., Baril, N.F., Jackson, B.R., Won, D.J., Zhang, F., Margine, E.R., Gopalan, V., Crespi, V.H., & Badding, J.V., Microstructured optical fibers as high-pressure microfluidic reactors. Science 311 (5767), 1583-1586 (2006).
10:30 AM - SM2.3.05
Multimaterial Fiber MEMS
Tural Khudiyev 1 , Jeff Clayton 4 , Etgar Levy 4 , Noemie Chocat 4 , Alexander Gumennik 3 , Alexander Stolyarov 4 , John Joannopoulos 4 , Yoel Fink 1 2
1 Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 4 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 3 , Indiana University, Bloomington, Indiana, United States, 2 Department of Materials Science and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractThe miniaturization of electromechanical transducers using bulk and surface micromachining processes has enabled the deployment of microelectromechanical systems (MEMS) in a variety of applications, from cell phones and ink-jet printers to drug delivery devices. A recently developed approach for the fabrication of multimaterial fiber devices presents a unique opportunity to realize MEMS in a novel form. Here we report a novel thermally drawn flexible MEMS fiber device based on P(VDF-TrFE-CFE) ferrorelaxor terpolymer. Electromechanical actuation capabilities of this fiber device are established using high voltage atomic force microscopy (HVAFM) and a record strain of >8% is demonstrated. For a fiber with an asymmetric geometry with respect to placement of the electrostrictive layer, a maximum transverse deflection of ~80 µm under an applied voltage of 200V DC is established using contact profilometry for a fiber fixed on one end and with a free length of 3.5 cm. Furthermore, fiber MEMS is demonstrated to function as a frequency or amplitude tunable cantilever-like flexible resonator scheme by altering fiber dimensions and applied voltage respectively. The potential of this approach to realize complex electromechanical systems in fibers is illustrated by the fabrication of an electrostrictive device capable of modulating a light source reflected off the bragg mirror surface of the fiber. Amplitude modulation of incident light through electric field induced deflection is demonstrated up to the second harmonic frequency of the fiber at 158.3Hz, and modulation depths up to 22.5% are reported; for an array of such fibers in PDMS, amplitude modulation is demonstrated at low frequencies with a modulation depth of 12.9%. These results pave the way to the realization of sophisticated MEMS in fiber, with potential applications in large surface area devices such as interactive haptic displays, acoustic modulators, and energy harvesting systems.
10:45 AM - SM2.3.06
Novel Method for Micro/Nano Patterning Using Fiber Thermal Drawing Technique
Dang Tung Nguyen 1 , Alexis Page 1 , Wei Yan 1 , Yunpeng Qu 1 , Tapajyoti Das Gupta 1 , Marco Volpi 1 , Fabien Sorin 1
1 , EPFL-IMX-FIMAP, Lausanne Switzerland
Show AbstractAn important feature of the fiber thermal drawing process is that it inherently generates surface area as the fiber is stretched. Such surfaces, when properly patterned at the micro and submicron scale, could be exploited in a wide range of applications such as hydrophobicity enhancement, opto-electronic devices, cell growth and tissue engineering, or even in microfluidics systems. Despite an increasing interest in advanced fibers and fabrics, however, the functionalization of fibers via the texturing of their surface at the sub-micrometer scale has not been realized. The thermal drawing process has an inherent limitation where curved surfaces with a relatively high interfacial tension will undergo thermal reflow leading to a smoothing out of small textures driven by Laplace pressure. This reflow happens faster as the pattern size gets smaller, which makes it very challenging to achieve sub-micrometer patterns on fibers surfaces. Here, we present a novel approach to alleviate this difficulty and realize fibers with sub-micrometer textures that reproduce uniformly along their entire length. We establish a model and demonstrate a strategy that allows for a drastic reduction of the polymer surface tension, hence reducing the Laplace pressure driven thermal reflow. We will show a variety of micro- and sub-micrometer architectures on top of thermally flat ribbons, circular fibers, and in the inner surface of hollow cavities. Patterned fibers and ribbons capable of covering large areas are assembled to form flexible surfaces with enhanced hydrophobicity, or with peculiar photonic attributes. We also demonstrate the use of textured fibers as molds to create inner-patterned soft polymer channels opening novel opportunities in microfluidics and bioengineering (Nguyen-Dang et al, Adv. Func. Mat. 2017).
SM2.4: Novel Fiber Structures
Session Chairs
Michael Rein
Sasha Stolyarov
Wednesday PM, April 19, 2017
PCC North, 100 Level, Room 122 A
11:30 AM - *SM2.4.01
Multimaterial Fibers—From Thermal-Drawing to Melt-Spinning
Ayman Abouraddy 1
1 , University of Central Florida, Orlando, Florida, United States
Show AbstractMultimaterial fibers combine a multiplicity of disparate materials of different optical, electrical, optoelectronic, and thermo-mechanical properties – combined in intimate contact to realize micro- or nano-scale transverse features that extend continuously along kilometers of length. Such fibers are expected to provide novel functionalities associated with electronic devices in a form-factor typical of an optical fiber with the goal of ultimately incorporating such fibers in future multifunctional textiles. In fabricating such fibers, many new phenomena emerge during the viscous flow of multiple materials in such confined nano-scale dimensions at elevated temperatures or upon axial extension at room temperature. In this talk, I review our recent progress in fabricating and characterizing such fibers. In particular, I review (1) our recent observations of thermally induced in-fiber fluid instabilities that produce spherical particles with arbitrary internal architectures, which we show can mold the flow of light in new ways; and (2) our recent observation of remarkable mechano-geometric instabilities associated with cold drawing of a multimaterial fibers.
The majority of current research on the fabrication of multimaterial fibers has focused on thermal drawing from a macroscopic preform. I will review our recent experiments on employing melt-spinning as a methodology for producing such fibers, which paves the way to the potential mass-production of multimaterial fibers at the scales consistent with the requirements of consumer textiles.
12:00 PM - SM2.4.02
Si-Ge Micro-Spheres of Prescribed Morphology from In-Fiber Capillary Breakup and Controlled Crystallization
Alexander Gumennik 1 , Etgar Levy 2 , Benjamin Grena 2 , Chong Hou 2 , Michael Rein 2 , Ayman Abouraddy 3 , John Joannopoulos 2 , Yoel Fink 2
1 , Indiana University Bloomington, Bloomington, Indiana, United States, 2 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 3 , University of Central Florida, Orlando, Florida, United States
Show AbstractIn the past few years, thermally-drawn multimaterial fibers have proven to be a unique platform for scalable fabrication of micro- to nanoparticles over a broad range of materials, through controlled in-fiber capillary breakup of the fiber components. Here, we report that the in-fiber breakup method offers advantages that go beyond scalability and materials versatility, in that it can be used to generate particles with structures unattainable to other synthesis methods. In particular, we show that we can produce Si-Ge Janus microparticles by solidifying alloyed droplets under a strong axial thermal gradient. We study the mechanism of Janus-type solidification by performing recrystallization experiments on silica-embedded particles using a diode laser. We demonstrate that fast cooling preferentially leads to dendritic microstructures with no orientation whereas slow cooling yields Janus-type morphologies. Lastly we report GPa-level compressive stresses within silicon particles solidifying in silica as another consequence of in-fiber constrained solidification. The ability to generate stressed silicon spheres or Si-Ge heterojunctions within microparticles could have great implications in the field of microelectronics. Furthermore, the integration of such particles within fibers could pave the way towards advanced integrated in-fiber electronic or optoelectronic devices.
12:15 PM - SM2.4.03
Diffusive Optical Coatings Loaded with Multiscale Composite Microspheres Produced from Multimaterial Fibers
Felix Tan 1 , Roxana Rezvani Naraghi 1 2 , Joshua Kaufman 1 , Ruitao Wu 1 , Behnaz Davoudi 1 , Aristide Dogariu 1 , Ayman Abouraddy 1
1 CREOL, The College of Optics & Photonics, University of Central Florida, Orlando, Florida, United States, 2 Department of Physics, University of Central Florida, Orlando, Florida, United States
Show AbstractRecent work has been demonstrated in which composite inorganic/organic microspheres were fabricated by means of a thermally induced fluid instability in multimaterial fibers [1-3]. These microspheres contain an organic, transparent matrix containing a random, well-dispersed distribution of inorganic, high-refractive-index nanoparticles. Due to the index contrast between the matrix and nanoparticle inclusions, the randomized distribution, and the size of the spheres, these composite microspheres exhibit diffusive scattering in the forward, backward, and sideway directions when unidirectionally irradiated with coherent light. This diffusive scattering, coupled with the very small degree of linear polarization, are indicative of multiple scattering events occurring throughout the volume of the microspheres. The resultant scattered field is not typical of homogeneous spheres as predicted by Mie scattering theory.
We build upon the prior results by quantitatively characterizing the spatial redistribution of the incident energy for varying microsphere diameter and for different relative volumetric concentrations of the nanoparticle inclusions. We directly compare these results to the case of a homogeneous microsphere of the same size, in addition to the results from simulations in which the field is exactly calculated using electromagnetic wave theory. Moreover, we will present a method for producing a large number of these composite spheres using bi-component nonwoven fabrics. The composite microspheres are then subsequently incorporated into a hundreds-micron-thick dielectric film from which the scattering properties are measured and compared against films loaded with the same volume concentration of nanoparticles alone.
[1] J. J. Kaufman, et al. "Structured spheres generated by an in-fibre fluid instability." Nature 487, 463-467 (2012)
[2] J. J. Kaufman, et al. "In-fiber production of polymeric particles for biosensing and encapsulation." PNAS (USA) 110, 15549 (2013)
[3] F. A. Tan, et al. "Diffusive Scattering from a Single Composite Microsphere Fabricated by an In-Fiber Fluid Instability." OSA Photonics & Fiber Technology Congress, Australian Conference of Optical Fiber Technology, Sydney, Australia, September 2016
12:30 PM - SM2.4.04
In-Fiber High Performance Monocrystalline Semiconducting Nanowires-Based Optoelectronic Devices
Wei Yan 1 , Dang Tung Nguyen 1 , Yunpeng Qu 1 , Tapajyoti Das Gupta 1 , Marco Volpi 1 , Alexis Page 1 , Fabien Sorin 1
1 , EPFL, Lausanne Switzerland
Show AbstractThe fabrication of electronic and optoelectronic devices at the tip of an optical fiber has recently attracted much interest in the physical and life sciences. The small cross-section and large aspect ratio of conventional optical fibers are however incompatible with the well-established wafer-based technologies suitable for planar and rigid substrates. Here, we report on a simple and scalable fabrication approach to realize, for the first time, high performance single crystal semiconductor nanowire-based devices at the tip of optical fibers. Our approach consists in two steps: first, a multi-material fiber is fabricated via the thermal drawing technique that integrates an optical waveguide surrounded by conducting electrodes in contact with semiconducting micro-wires. Second, a solution-based nanowire growth approach is applied to the fiber tip which induces the simultaneous formation of a dense array of high quality semiconducting nanowires and their electrical contact with the integrated electrodes. We will show a full characterization of the optoelectronic properties of these fiber-integrated devices, that exhibit sensitivities and bandwidths orders of magnitude better compared to existing thermally drawn optoelectronic fiber configurations. We will also demonstrate that this simple scheme can be applied not only at the fiber tip, but also along the entire fiber length. This paves the way towards the fabrication of nanowire based devices at the scalability, flexibility and cost associated with optical fibers. Such nanowire-based fiber integrated optoelectronic devices can find applications in remote optical sensing, minimally invasive in situ and in vivo probing and imaging of biological tissues, as well as large area, flexible optoelectronics and energy harvesting systems.
12:45 PM - SM2.4.05
Surface-Patterned Fiber
Chong Hou 1 , Tural Khudiyev 1 , Alexander Stolyarov 1 , Yoel Fink 1
1 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractEvery year over 100 billion pounds of man-made fiber is produced for the textile industry. Most of these will undergo some form of chemical treatment to achieve properties ranging from color to hydrophobicity, antimicrobials, UV-protection and others. These chemical-based textile surface functionalization treatments come with significant societal penalties, including adverse health and environmental effects as well as tremendous energy expenditures. Therefore, alternative and sustainable strategies to achieve textile surface functionality is highly desired. Here we present a chemical-free, all-structural fiber surface patterning technique that can facilitate textile functionality while at the same time is safe, environmentally friendly, and cost effective.
First, this is the only existing technique that concurrently enables high spatial resolution (sub-micron scale) patterning over km-long lengths on flexible polymer substrates with high spatial uniformity (~1%) and at throughputs necessary for textile fiber production.
Second, we demonstate the fabrication of complex surface topologies on planar fiber surfaces, including: gradient surfaces, hierarchical surfaces, 2D features, and different grating shapes.
Third, we demonstrate two unique applications of this material processing approach: i) sub-wavelength diffraction grating on the surface of fiber and ii) anisotropic surface wetting phenomenon.
Forth, we demonstrate a textile woven with these fibers that exhibits hydrophobic properties.
This surface patterning technique can enable a range of unique device and textile architectures thereby enabling numerous opportunities in emerging research fields, from smart textiles to organic nanophotonics and microfluidics.
SM2.5: Novel Textiles
Session Chairs
Guangming Tao
Cheng Zhang
Wednesday PM, April 19, 2017
PCC North, 100 Level, Room 122 A
2:30 PM - *SM2.5.01
Multimaterial Photonic Fabrics
Alexander Stolyarov 1 , Tural Khudiyev 1 , Chong Hou 1 , Michael Rein 1 , Yoel Fink 1
1 , Massachusetts Institute of Technology Lincoln Laboratory, Lexington, Massachusetts, United States
Show AbstractThe past decade has witnessed tremendous growth in the field of multimaterial fiber devices, yet the challenges and opportunities of integrating multimaterial fibers into functional textile systems have remained largely unexplored. In this presentation, I will highlight several recent breakthroughs in multimaterial textile systems. Examples will include photonic fabrics with controlled reflectivity, light emitting textiles and composites, textiles with programmable color change, and others. Facilitating this work is the nation-wide collaborative infrastructure assembled under the Advanced Functional Fabrics of America, serving as the rapid prototyping engine for propelling the country’s manufacturing innovation in revolutionary fibers and textiles.
The Lincoln Laboratory portion of this material is based upon work supported by the Assistant Secretary of Defense for Research and Engineering under Air Force Contract No. FA8721-05-C-0002 and/or FA8702-15-D-0001. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Assistant Secretary of Defense for Research and Engineering.
3:00 PM - SM2.5.02
Characterization of Thermal Protective Fabric Materials under Fire Exposure
Sumit Mandal 1 , Simon Annaheim 1 , Martin Camenzind 1 , Rene Rossi 1
1 , Empa, Swiss Federal Laboratories for Materials Science and Technology, St. Gallen Switzerland
Show AbstractIn 2014, it was reported that nearly 8,238 fire incidents occurred in Switzerland and that resulted in more than 150 firefighter injuries. Notably, in the United States, the number of fire incidents and firefighter injuries were extremely high with approximate numbers reaching up to 1,298,000 and 63,350, respectively. It has been stated that the majority of these firefighter injuries occurred due to the inadequate performance of their thermal protective clothing. Considering this, a great deal of research has studied the thermal protective performance of fabric materials used in the clothing under flame and/or radiant-heat exposures [1, 2]. However, the holistic understanding of the thermal protective performance of fabric materials under overall fire exposures (e.g., flame, radiant-heat, and flash fires) is still limited, fragmented, and ambiguous.
This study aims to investigate the thermal protective performance of fabric materials under high intensity fire exposures. The performance of thermal protective fabric materials (single- and multi-layered) with different physical properties (weight, thickness, air permeability, thermal resistance, and evaporative resistance) was predicted under laboratory conditions applying the standard small-scale flame (ISO 9151:1995) and radiant-heat (ISO 6942:2002) exposure tests. Additionally, the protective performance of fabric materials was predicted, in terms of time required to generate second-degree burns on firefighters’ bodies, under the flash fire exposures using a newly developed hexagon test method. The effect of fabric features on the protective performance was statistically analyzed and explained through the fundamental theory of heat and mass transfer. Also, the protective performance values obtained from the small-scale (flame and radiant-heat) and hexagon (flash fires) tests were compared and scientifically discussed.
In this study, it has been found that fabric structure (e.g., number of layers, position of layers) and properties (e.g., weight, thickness) have a significant effect on the protective performance of fabric materials under the selected fire exposures. Additionally, the configuration of the fire exposure tests (e.g., experimental set-up, heat flux) and modes of heat transfer through the fabrics (e.g., convection, radiation) do considerably affect the protective performance of fabric materials.
The findings from this study will help textile or materials engineers in designing and selecting the functional fabric materials in order to develop the customized thermal protective clothing for a specific fire environment. This development will advance the functional textiles field by improving the health and working performance of firefighters across the world.
References:
1. Song, G., Mandal, S., & Rossi, R. (2016). Thermal Protective Clothing for Firefighters. England: Woodhead Publishing.
2. Schmid, M., Annaheim, S., Camenzind, M., & Rossi, R. (2016). Fire and Materials. DOI: 10.1002/fam.2362
3:15 PM - SM2.5.03
Multi-Material Fibers for Electromechanical Touch Sensing
Alexis Page 1 , Dang Tung Nguyen 1 , Yunpeng Qu 1 , Marco Volpi 1 , Wei Yan 1 , Fabien Sorin 1
1 , EPFL - IMX - FIMAP, Lausanne Switzerland
Show AbstractThe thermal drawing process originally used to fabricate optical fibers has recently been shown to be compatible with a broader range of materials that can be combined in complex cross-sectional architectures. This simple approach can now enable the integration of conducting, insulating and semiconducting components in multi-material fibers to realize functional fiber devices not only for optical transport but also for optoelectronic, sensing or biomedical applications. So far however, multi-material fibers have been designed to work while keeping a fixed shape in the cross-sectional plane. On the other hand, MicroElectroMechanical systems (MEMS) frequently employ moving parts such as cantilevers for sensing or actuation. In this contribution, we demonstrate that the design of fiber devices can be inspired by the MEMS technology and comprise freely moving domains to deliver a given functionality. We show in particular the fabrication of a MicroElectroMechanical fiber (MEMF) that acts as a touch sensing device that relies on a free standing conductive polymer sheet that can locally bend upon an applied pressure. This mechanical actuation can bring the bending sheet in contact with a second conducting polymer domain, creating an electrical signal that allows the fiber device to precisely detect and locate a pressure point along its length. We also show that the information on presence and position of a pressure applied can be decoupled from the measurements using an appropriate electrical circuit. This allows programming a fiber device that could act as a flexible electronic interface integrated within different supports such as smart textiles and medical fabrics in a variety of configurations.
SM2.6: Fibers in Bioengineering
Session Chairs
Guangming Tao
Cheng Zhang
Wednesday PM, April 19, 2017
PCC North, 100 Level, Room 122 A
4:30 PM - *SM2.6.01
Multimaterial Multifunctional Fibers for Electrical, Optical and Chemical Interrogation of Neural Circuits
Xiaoting Jia 1
1 Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia, United States
Show AbstractIn recent decades, there has been significant development in neural interface devices, expediting the understanding of neural circuits as well as the treatment of neurological disorders. However, most of the existing neural interface devices are either based on hard materials such as metal or silicon, which can cause long-term tissue damage, or based on flexible film substrates which are mainly used to probe the surface of the brain. Furthermore, it is a challenge to incorporate optical, chemical or other functionalities into electrical recording probes in order to establish two-way communication with neural circuits in vivo. Here I present a multimaterial multifunctional fiber based platform for interrogation of neural circuits in vivo. These fibers are capable of simultaneous electrical, optical and chemical communication with neural circuits in the deep brain regions. And their small feature size and low bending stiffness leads to high biocompatibility and minimum tissue damage in the brain. This fiber based platform could facilitate both fundamental understanding of the functional neural networks as well as clinical applications in treating brain related diseases.
5:00 PM - SM2.6.02
Stretchable Fibers for Optoelectronic Probing of Spinal Cord Circuits
Chi Lu 1 , Seongjun Park 1 , Alex Derry 1 , Thomas Richner 2 , Chet Moritz 2 , Yoel Fink 1 , Polina Anikeeva 1
1 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 2 , University of Washington - Seattle, Seattle, Washington, United States
Show AbstractWhile the majority of the neural engineering efforts of the past decade have focused on interfaces with the brain, fundamental understanding of the spinal cord neural dynamics remains limited by the tools capable of recording and modulation in this organ. In addition to its sophisticated neurophysiology, flexibility and repeated deformations of the spinal cord present a challenge to engineering of implantable devices. Fueled by advances in optogenetics, optoelectronic probes have recently enabled cell-specific neural stimulation compatible with concomitant recording of neural activity. The mechanics of the spinal cord, however, remain difficult to match with hard materials traditionally used in optoelectronics.
Here we address the elastic modulus mismatch by designing flexible multifunctional neural probes capable of conforming to the spinal cord geometry and mechanical properties, while providing optical stimulation and neural recording.
We mimicked the fibrous and flexible morphology of the spinal cord and fabricated all-polymer fibers that consist of a polycarbonate (PC) and cyclic olefin copolymer (COC) waveguide and carbon-polyethylene (CPE) composite electrodes. The polymer fiber probes enabled low-loss light transmission 0.5-2 dB/cm even under repeated deformation at bending radii < 1 mm. The conductive polymer composite electrodes exhibited tip impedance 1-3 MΩ suitable to record local field potentials. To further reduce the impedance, we have fabricated concentric device by dip coating PC/COC waveguides (~100 µm in diameter) with a 1 µm thick conductive mesh of silver nanowires (AgNWs). The devices were then encapsulated with a layer of poly(dimethylsiloxane) (PDMS) to a total diameter of 130 µm to protect the AgNW mesh from degradation, while maintaining high flexibility (under review). Exposed AgNW mesh ring-electrodes possessed low impedance (~200 kOhm) and were capable of recording isolated action potentials in the mouse spinal cord with high signal-to-noise ratio (SNR 7±1) and low noise level (10 ±3 μV). We also applied the dip coating approach to fibers made of cyclic olefin copolymer elastomers (COCE). COCE is a rubbery material allowing us to produce stretchable electrodes for neural recording. The COCE/AgNW fiber electrodes maintained their conductivity at 100 % extension strain, and could be deformed repeatedly without hysteresis at 20 % strain.
We demonstrated the utility our devices for recording and optical stimulation in the spinal cord of transgenic mice expressing the light sensitive protein channelrhodopsin 2 (ChR2). Furthermore, we found that optical stimulation of the spinal cord with the polymer fiber probes induces on-demand limb movements. Finally, we illustrated that the modest dimensions and high flexibility of our devices permit chronic implantation into mouse spinal cords with minimal damage to the neural tissue.
5:15 PM - SM2.6.03
Forcespun Nanofibrous Membranes of Gelatin/Poly(epichlorohydrin-co-ethylene oxide) and Biocompatibility Study for Tissue Engineering Applications
Narsimha Mamidi 1
1 , ITESM, Monterry Mexico
Show AbstractGelatin/poly(epichlorohydrin-co-ethylene oxide) [GL/PECH-EO] nanofibrous membranes were developed by forcespinning (FS). We found that the combination of PECH-EO tremendously improved the forcespinnability of gelatin. Both the random and aligned GL/PECH-EO fibers were developed by varying the concentration ratio of both PECH-EO and gelatin. The fiber diameter, mechanical, surface wettability, fiber degradation, biocompatibility properties were controlled by varying the blending ratio of gelatin/PECH-EO and force spinning parameters. The GL/PECH-EO fibers were showed improved mechanical properties compared with pristine GL fibers (controller). In addition, drug release and antibacterial activity of forcespun nanofibrous membrane were measured by incorporation of Berberine chloride drug. In the presence of Berberine drug notable changes were observed in mechanical, fiber morphology and antibacterial properties. The biocompatibility (adhesion, growth, proliferation, metabolic activity, and viability) also investigated using human fibroblast cells. The mechanical and cytotoxicity results demonstrated that GL/PECH-EO fibers could be promising substitutes for tissue regeneration, wound healing and hernia repair.
5:30 PM - SM2.6.04
Implantable Polymer Composite Electrode with Carbon Nano Fibers (CNF) Aligned during Thermal Drawing as a Reliable Chronic Neural Interface
Yuanyuan Guo 2 , Shan Jiang 3 , Benjamin Grena 1 , Ian Kimbrough 4 , Yoel Fink 1 , Harald Sontheimer 4 , Tatsuo Yoshinobu 2 , Xiaoting Jia 3
2 Department of Biomedical Engineering, Tohoku University, Sendai Japan, 3 Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States, 1 Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 4 Carilion Research Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States
Show AbstractTechnology development for obtaining extracellular action potentials from selective neurons with high-fidelity and biocompatibility are essential for basic neuroscience and also indispensable to the emerging development of neuroprostheic devices. Implantable micro-electrode technologies, especially those based on micro-wires and silicon, have demonstrated their capability for recording, thanks to their miniature size and intrinsic good signal-to-noise ratio. However, due to their stiffness and biocompatibility issues, minimizing tissue response as well as prolonging functional durations are critical and there is an ongoing endeavor for the improvement of this micro-electrode technology.
In the previous studies, we have pioneered a new class of implantable neural probes based on flexible and biocompatible polymer fibers, which were mass-produced via thermal drawing process. They integrated multi-functionalities and demonstrated stable chronic performance over the extended period of implantation. However, due to the low conductivity of polymer materials we chose as electrode, i.e., carbon loaded polyethylene (CPE), the recording site had to be sufficiently large to maintain the moderate impedance for capturing single-neuron activities. Therefore, there has been ongoing push for developing new polymer composite materials which can improve electrical characteristics to serve as functional chronic implantable electrodes. In the meantime, they should be much reduced in size, more flexible but also reasonably robust.
Here we report the development of a new composite electrode consisting of aligned carbon nano fibers(CNF) within the carbon loaded polyethylene (CPE) prepared by thermal drawing process. The resulting implantable fiber probes have dimensions of 50 µm by 50 µm, an order of magnitude smaller than the previously developed fiber probes. Within this probe, the recording site of the CNF composite material has significantly reduced size of around 15 µm x 15 µm. They were found to have much better S/N ratio in the single-neuron recording in both acute and chronic experiments in wild type mice. This superior performance can be explained by the alignment of CNF within the CPE along the extensional direction during the thermal drawing process. This CNF alignment has demonstrated the increase of the longitudinal electrical conductivity by two orders of magnitude, but still keeps the composite mechanically compliant with brain tissues. The histological results showed much reduced chronic reactive tissue response and suggested its stable compatibility over a long period. In this study, a new flexible, biocompatible and highly conductive composite material is developed which makes the fundamental advances in micro-electrode technology that will eventually benefit both basic and applied neuroscience.
5:45 PM - SM2.6.05
Multimaterial Porous Fibers as Neural Scaffolds
Benjamin Grena 1 , Seongjun Park 1 , Jun Sang Moon 1 , Yoel Fink 1 , Polina Anikeeva 1
1 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Show AbstractNerve guidance channels are synthetic porous conduits placed at the location of a nerve injury, and aimed at promoting regeneratoin of the injured nerve. Despite a large body of work on the chemical and physical cues promoting nerve regeneration, most nerve guidance channels to-date do not take advantage of all these cues. Here, we present results on preform-to-fiber thermal drawing as a fabrication platform for multifunctional porous neural scaffolds, capable of interacting with nerves through various modalities. First, we show how we can use phase separation of a polymer solution in a preform reservoir to generate porous domains in the thermally-drawn fibers. Second, we present a mthod to promote intra-layer adhesion and build complex multimaterial fibers incuding porous domains. Last, we demonstrate the scaffold viability by growing neurons in vitro into our fibers, and conduct experiments on the influence of geometry, optical stimulation, and electrical stimulation on neurite regrowth.
SM2.7: Poster Session
Session Chairs
Michael Rein
Max Shtein
Guangming Tao
Thursday AM, April 20, 2017
Sheraton, Third Level, Phoenix Ballroom
9:00 PM - SM2.7.02
The Preparation and the Properties of Novel Carbonized Polyacrylonitrile/Silica Core-Shell Nanofiber
Hung-Fan Lee 1 , Pei-Chin Wang 1 , Yui Whei Chen-Yang 1 2
1 Chemistry, Chung Yuan Christian University, Taoyuan City Taiwan, 2 , Nanotechnology and Center for Biomedical Technology, Chung Yuan Christian University, Taoyuan Taiwan
Show AbstractIn this study, the novel carbonized polyacrylonitrile/silica (C/SiO2) core-shell nanofiber is fabricated via the coaxial electrospinning technique followed by the heat treatment. The effects of viscosity of the electrospinning solution, feed rate, and applied voltage in the experiment on the formation of the nanofiber were investigated. The best parameters for optimizing the morphology of the nanofiber were obtained by investigation the SEM images. The properties of the nanofiber are studied by the combination of TEM, FT-IR, EDS, XRD, BET, GPA, EC, tension test, contact angle, and water uptake measurements. The results show that the conductivity and mechanical strength of C/SiO2 are 2.66 x 10-2 S/cm and 2.1 MPa, respectively. It indicates that after the carbonization, the conductivity and mechanical strength of the as-prepared C/SiO2 nanofiber mat are higher than that of the pure carbon nanofiber mat for approximately 77 and 40 %, respectively. The gas permeability is 1.69 x 10-2 cm3 (STP) cm/sec cm2 cm-Hg, which is similar to that of the carbon nanofiber mat. Besides, the water uptake of C/SiO2 nanofiber is also significantly higher than that of the pure carbon nanofiber. This result is ascribed to the hygroscopic mesoporous silica of the core, in which the pores of the silica core is believed to interconnect with the pores of the carbon shell, leading to the improvement in water uptake. In all, this novel core-shell material with the improved properties is a potential material for many applications such as energy, filtration, and support.
9:00 PM - SM2.7.03
Electrically Conductive Glass-Carbon Composites
Guangming Tao 1 , Shi Chen 1 , Sudeep Pandey 1 , Ayman Abouraddy 1 , Romain Gaume 1
1 CREOL, University of Central Florida, Orlando, Florida, United States
Show AbstractWe report the synthesis and characterization of a glass-carbon composite with high electrical conductivity in excess of 1800 S/m at the room temperature.
Symposium Organizers
Michael Rein, Massachusetts Institute of Technology
Max Shtein, University of Michigan-Ann Arbor
Guangming Tao, University of Central Florida
SM2.8: Fiber Electrospinning
Session Chairs
Thursday AM, April 20, 2017
PCC North, 100 Level, Room 122 A
9:45 AM - *SM2.8.01
Centrifugally-Spun Nanofibers for Advanced Energy Storage
Xiangwu Zhang 1
1 , North Carolina State University, Raleigh, North Carolina, United States
Show AbstractNanofibers are an important class of material that is useful in a variety of applications, including filtration, tissue engineering, protective clothing, composites, battery separators, energy storage, etc. So far, electrospinning is the most studied method for producing nanofibers. A literature search using the Web of ScienceTM database shows that Year 2015 alone had publication of over 3000 articles in the electrospinning of nanofibers. Among these publications, over 50% focused on the investigation of the electrospinning process and the characterization of the resultant nanofibers, and the others mainly address the innovative use of electrospun nanofibers for various applications. However, the wide-spread commercial use of electrospinning is limited due to its low production rate, poor safety, and high cost. Most other nanofiber production methods, such as phase separation, template synthesis, and self-assembly, are complex and can only be used to make nanofibers from limited types of materials. This presentation introduces a simple, yet versatile technique for producing nanofibers of various materials including polymers, carbons, ceramics, metals, and composites. Centrifugal spinning eliminates the limitations encountered by current nanofiber production methods and can produce nanofibers at high speed and low cost. Centrifugally-spun nanofibers can be used in various applications, including filtration, tissue engineering, protective clothing, composites, battery separators, energy storage, etc. The application of centrifugally-spun nanofibers in energy storage applications will be discussed in this presentation.
10:15 AM - SM2.8.02
Hierarchically Porous Electrospun Nanofiber/Metal-Organic-Framework Nanocomposites for Adsorption Applications
Mitchell Armstrong 1 , Bin Mu 1
1 , Arizona State University, Tempe, Arizona, United States
Show AbstractElectrospun fibers are becoming an increasingly important field of research in academia due to impressive control over size and functionality. A faction of the electrospun fiber research is interested in embedding particles into the fibers to further increase functionality, including the use of metal-organic-frameworks. This work is focused on increasing the loading and accessibility of MOFs inside fibers through a mechanism involving selective polymer removal to form hierarchically porous fibers, and probing their adsorptive properties.
10:30 AM - SM2.8.04
Iron-Doped Apatite Nanoparticles Delivered via Electrospun Fiber Mesh for Maximized Bacterial Killing by Bacteriophage
Jessica Andriolo 1 2 , Gary Wyss 2 , Marisa Pedulla 2 , M. Hailer 2 , Jack Skinner 2
1 , University of Montana, Missoula, Montana, United States, 2 , Montana Tech, Butte, Montana, United States
Show AbstractIt has been shown that iron-doped apatite nanoparticles (IDANPs) enhance bacterial killing by bacteriophage (phage) when bacteria cells are pre-exposed to IDANPs prior to phage introduction. This effect has been demonstrated across gram-positive and gram-negative bacterial species as well as with the use of phage of various tail morphology and genetic material. Bacterial lawns grown from cells that were pre-exposed to IDANPs have experienced as high as double the amount of plaques in vitro as compared to controls. The biocompatible nature of apatite coupled with the ability of phage to serve as a therapeutic alternative to traditional antibiotics make this effect of interest for medical applications. In the presented research, investigators took this work a step further in an attempt to create a treatment delivery system for IDANPs as an adjuvant to phage therapy. Previous work by Korehei et al. utilized electrospinning (ES) to create coaxial fibers made of biocompatible polymers which carry phage inside a microfluidic channel within individual fibers. The same researchers also used polyethylene oxide(PEO)/cellulose diacetate(CDA) polymeric blends to slow phage release. To compliment such a treatment delivery system, a PEO fiber mesh has been created, which allows rapid release of IDANPs. In this work, it was determined that IDANP-exposed bacteria had maximum increased susceptibility to death by phage when cells were exposed to IDANPs for 1 hour prior to the addition of phage. Therefore, it was determined that a fiber mesh treatment delivery system which delivers phage and IDANPs should be constructed so that IDANPs are released quickly and exposed to bacteria cells for a specified amount of time prior to phage release via deeper fiber layers. PEO fibers doped with IDANPs were constructed via ES and demonstrated dissolution within seconds of exposure to an aqueous environment. Subsequent collection of the dissolved fibers was analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy to confirm IDANPs were released from fibers. PEO/IDANP fibers were also deposited onto a polycaprolactone (PCL) fiber mesh containing coaxial PCL fibers to demonstrate fabrication of a treatment delivery system composed of rapid-release PEO/IDANP fibers electrospun onto a slow-release coaxial fiber mesh. Further work aims to test the composite material for bactericidal effectiveness on various bacterial species. IDANPs were synthesized using wet chemical precipitation methods. PEO (Mv 100k) was prepared at 13 wt% in methanol with or without IDANPs at a concentration of 6.85 mg/mL. ES was performed at a spinneret to collection plate distance of 7.62 cm, an applied voltage of 12.8 kV, and polymer was delivered at a flow rate of .01 mL/hr. Coaxial PCL fibers were prepared at 8 wt% in trifluoroethanol. SEM samples were gold coated prior to observation. Transmission electron micrographs were collected and examined on carbon-formvar coated grids.
11:15 AM - *SM2.8.05
Multifunctional and Smart Fibers Designed and Prepared via Organic/Inorganic Hybrid Technology
Zexu Hu 1 , Wujun Ma 1 , Kai Hou 1 , Hengxue Xiang 1 , Xiaogang Luo 1 , Wei Weng 1 2 , Zhe Zhou 1 2 , Lijun Yang 2 , Yuze Tang 2 , Meifang Zhu 1
1 State Key Laboratory for Modification of Chemical Fibers & Polymer Materials, College of Material Science & Engineering, Donghua University, Shanghai China, 2 , Xuguang Fiber Science and Technology Co. Ltd., Shanghai China
Show AbstractOrganic-inorganic hybrid technology (OIHT) can achieve the multi-scale composites of organic polymers and inorganic materials in the nano or molecular level. OIHT-based hybrid materials can not only exert O/I component’s characteristics but even amplify their unique collaboration features of O/I. In this talk, a series of O/I hybrids with controlling over the morphological structure, the interface interaction and functions as well as applications have been investigated. We introduce OIHT in the development of fiber and textiles in three main techniques: in-situ polymerization, advanced blending and fiber surface engineering. The high quality and multi-functional fibers such as nylon 6 fibers with flame retardant property, multifunctional composite polyester (PET) fibers, flexible wearable graphene/poly (vinyl alcohol) (PVA) fibers and etc. Recently, flexible and wearable electronics (FWEs) are very promising in the fields of professional activities, sports/health monitoring, as well as personal fashion and entertainments. However, the traditional energy storage devices are bulky and heavy which could not meet the demands of FWEs. Therefore, we developed a variety of continuous carbon-based hybrid fibers by scalable wet-spinning, then assembled them into flexible solid-state fiber-based supercapacitors (FSCs). These FSCs are slim, flexible and weavable, which may act as green, safe and fast power sources for FWEs. Novel smart hybrid fibers such as PVA/rGO were produced for robust wearable FSCs，with enhanced strength, toughness, and specific capacitance due to the strong PVA-rGO interface and hydrophilicity of PVA. The PVA/GO fibers by weight ratio of 10/90 possess the strength of 186 MPa and toughness of 11.3 J cm-3. The assembled FSC-2 delivers an energy density of 5.97 mWh cm-3 at 26.9 mW cm-3, featuring excellent flexibility and bending stability. It is robust enough to be weaved into a textile and thus promising as wearable power supply for smart garments.
We acknowledge the financial supports from Natural Science Foundation of China (51673038), Shanghai Key Project(16JC1400700), Program for Changjiang Scholars and Innovative Research Team in University (T2011079, IRT1221), as well as Program of Introducing Talents of Discipline to Universities in China (111-2-04).
11:45 AM - SM2.8.06
Hybridizing Millimeter Long Carbon Nanotubes with Electrospun Fabrics for High Performance Electrically Conductive Textiles
Ozkan Yildiz 1 , Philip Bradford 1
1 , North Carolina State University, Raleigh, North Carolina, United States
Show AbstractDue to the low mechanical properties of electrospun nonwoven fabrics, they cannot be used in most applications even though they have unique properties such as small fiber diameter, high surface area, high porosity and small pore size. The addition of CNTs into polymer electrospun fibers has attracted many researchers, because of the CNTs’ high mechanical, electrical and multifunctional properties. However, this method has been generally unsuccessful due to difficulty of dispersion, low volume (or weight) content, and short length required of the CNTs. A novel processing technique was created to address these limitations and improve final nanofiber nonwoven properties. CNT – polymer hybrid nonwoven fabrics were created by simultaneously winding continuous drawn CNT sheets from millimeter long aligned CNT arrays onto an electrically grounded mandrel that served as the collector for the electrospun fibers. This technology overcomes the numerous physical and mechanical limitations of traditional electrospun nonwovens. The mass fraction of CNTs in the hybrid fabrics can be easily controlled by adjusting the take up speed of the rotating mandrel during the process. The hybrid fabrics show extremely high strength, small pore size, high specific surface area and electrical conductivity. The flexibility of this nanofabrication method allows for the use of many different polymer systems, which provides the opportunity to use in wide range of applications. In this study, this novel processing technique was implemented to produce CNT-Si sheet hybrid anode materials. The high capacity, binder-free, flexible CNT-Si sheet hybrid anode materials were prepared through a hybridization of high aspect ratio CNTs and PMMA-Si electrospun fabrics, and then subsequent heat treatment processes. The uniform deposition of electrospun fibers provided homogenous Si deposition inside the CNT sheets. The novel hybridization technique provided more free volume for Si expansion, which in turn improved the cycling performance of CNT-Si sheet hybrid anode materials. To further improve the long-term cycling performance, an additional nano-scale pyrolytic carbon layer was added using a CVD technique. Electrochemical performance results showed that the CVD carbon-coated flexible CNT-Si sheet hybrid exhibited high capacity retention of 90.2% and a high coulombic efficiency of 98% at the 100th cycle. The hybrids are a promising anode material candidate for next-generation flexible and high-energy lithium-ion batteries.
12:15 PM - SM2.8.08
Thermoresponsive Janus Membrane Using Electrospun Poly(N-isopropylacrylamide)/Poly(vinylidene fluoride) Fibers
Anupama Sargur Ranganath 1 , Avinash Baji 1
1 , Singapore University of Tech and Design, Singapore Singapore
Show AbstractJanus membranes are designed to have an asymmetric architecture such that the two components with incompatible chemistry or morphology function as one system. They have gained immense attention for their unique functionalities such as unidirectional liquid or air penetration due to their anisotropic architecture. They can be employed for many applications such as waterproof breathable membranes, interface stabilizers, biological sensors, and drug delivery systems. In this study, we use a two-step electrospinning technique to produce anisotropic architecture based on poly(N-isopropylacrylamide)/poly(vinylidene fluoride) (PNIPAM/PVDF) membranes. The membranes consist of thermoresponsive PNIPAM/PVDF blend fibers on one side and neat PVDF on the other side. Our results demonstrate that the blend membrane is superhydrophilic below 32°C and highly hydrophobic above 32°C. Additionally, we demonstrate that the anisotropic property of this thermoresponsive composite membrane can be controlled with temperature. At ambient temperatures, the membrane exhibited anisotropic wettability property with hydrophilic/hydrophobic composite membrane. This anisotropic property facilitates the pressure gradient for unidirectional liquid transport. At elevated temperatures, anisotropic property is reduced due to the hydrophobicity of the thermoresponsive membrane, which ceases the liquid transport. At room temperature, the water droplet (5µl) penetrated from the hydrophobic PVDF side in 7 seconds. However, at elevated temperature, water fails to penetrate from either side of the membrane. This is attributed to the thermoresponsive membrane that switches its wettability with the change in temperature of the system. Thus, these results show tremendous potential of using electrospun fibers as smart materials with thermoresponsive wettability.
12:30 PM - SM2.8.09
Steering Surface Topographies of Electrospun Fibers for Controlled Drug Release and Tissue Engineering Applications
Rene Rossi 1 , Goekce Yazgan 1 , Giuseppino Fortunato 1
1 , Empa, St Gallen Switzerland
Show AbstractElectrospun nanofiber networks are increasingly used in filtration, drug delivery, sensing or tissue engineering applications. As the interface between the fibrous meshes and its environment is a key factor for their use, a profound understanding on how to tailor the morphology of the fibers is needed in order to obtain controlled fiber properties (e.g. surface chemistry or substance diffusion).
In order to alter surface topographies of electrospun fibers, two main principles have emerged: 1) post-treatment procedures to add structural components or to selectively remove compounds from the fibers or 2) exploitation of phase separation processes during fiber formation for selective and time dependent drying and crystallization processes. The second approach involves the precise control of spinning solution properties such as appropriate selection of solvent mixtures with defined evaporation rates and water miscibilities, polymer solubility as well as controlling the environmental factors such as relative humidity and temperature. In this way, selective degrees of textures can be obtained, from smooth to highly porous fiber surfaces.
In this study, we used a simulation tool (Hansen solubility parameters – HSP) to choose solvent / non-solvent systems and to evaluate the solvent evaporation processes as well as water vapor condensation during the fiber formation process and thus predict the fiber surface structure. We used different solvent mixtures and relative humidity conditions to produce polycaprolactone fibers with defined surface morphologies. Environmental water vapor condensation during the fiber formation process led to phase separation of the polymer solution and the formation of a surface porous structure. As the surface-to-volume ratio was modified, these structures influenced the diffusion rate of active agents as well as the mechanical properties of the electrospun mesh and thus open new perspectives for controlled drug delivery and tissue engineering applications.
SM2.9: Nanofibers and Nanoscale Phenomena in Fibers and Textiles
Session Chairs
Alexander Gumennik
Sasha Stolyarov
Thursday PM, April 20, 2017
PCC North, 100 Level, Room 122 A
2:45 PM - *SM2.9.01
Microfiber-Based Microcavities and Miniaturized Fiber Stereo Devices
Yan-qing Lu 1 , Fei Xu 1
1 , Nanjing University, Nanjing China
Show AbstractRecently, microcavities based on subwavelength-diameter optical microfibers have emerged as ideal elements for fiber circuits because of their small size, low cost, low loss, and very large evanescent fields. There are two approaches primarily employed for the microfiber-based microcavity with 1D or 3D geometry. The first strategy involves engineering the straight microfiber to realize miniature F-P cavities and gratings. The second strategy deals with the wrapping-on-a-rod technology, a 3D micro-resonator with a strong evanescent field can be fabricated by wrapping a microfiber multiple times on a microrod, which forms a miniaturized fiber stereo device (MFSD).
In this talk, we would introduce several kinds of 1D and 3D microcavities based on microfibers and their applications in sensing and lasing. In addition, based on the idea of MFSD, we further propose and demonstrate a reliable approach to fabricating graphene–microfiber structure (GMF)-integrated devices by wrapping a microfiber on a graphene modified rod. This method is much simpler than the conventional integration techniques because we only need to coat a small piece of graphene on a thick rod, rather than a thin microfiber. Theoretically, with a strong evanescent field, the GMF interaction length can be arbitrarily increased using a spring shape of as many turns as is spatially possible. Owing to the extremely asymmetrical cross section of such a stereo GMF device and the nature of the graphene–light interaction, different types of losses occur in the two fundamental modes in this hybrid structure. A broadband polarizer can be naturally integrated into such a device. Furthermore, we show that the stereo GMF structure can also operate as a polarization-dependent, all-optical graphene modulator at approximately 1550 nm, with a high modulation depth and modulation efficiency, which are more than one order of magnitude larger than those reported previously. This type of miniaturized fiber stereo, in-line, all-optical modulator has great potential in fiber optical communications, in which there are demands for high-speed, wideband, low-cost, and integrated methods to modulate information.
3:15 PM - SM2.9.03
Ultrafiltration Membranes Surface Modified with Electrospun Nanofibers Exhibit Enhanced Flux and Fouling Resistance
Kerianne Dobosz 1 , Christopher Kuo-LeBlanc 1 , Tyler Martin 1 , Jessica Schiffman 1
1 , University of Massachusetts Amherst, Amherst, Massachusetts, United States
Show AbstractPolymer membranes are an enabling technology that allows society to meet the ever growing demand for clean water. Previous research has aimed to improve the hydrophilicity and fouling resistance properties of membranes. Unfortunately, improvements made to one membrane property often adversely affects another. For example, increases in flux often reduce membrane selectivity. Here, electrospun nanofibers are investigated as an ultrafiltration membrane-surface coating to improve membrane performance without adversely impacting membrane permeability. Cellulose (CL) and polysulfone (PSf) nanofiber layers with an equivalent average diameter and the same fiber morphology were electrospun. When applied as a top layer, the nanofibers did not change membrane selectivity as confirmed by molecular weight cut-off experiments. Pure water flux persisted at lower applied pressure and increased for the PSf nanofiber-membrane composites at higher applied pressure. As a result of a CL or PSf nanofiber layer, membrane fouling resistance improved, as demonstrated by decreased protein retention. This work demonstrates that high porosity electrospun nanofibers hold potential to serve as a versatile materials platform to improve the performance of ultrafiltration membranes.
3:30 PM - SM2.9.04
Personal Thermal Management by Metallic Nanowire-Coated Textile
Po-Chun Hsu 1 , Xiaoge Liu 1 , Chong Liu 1 , Yi Cui 1
1 , Stanford University, Stanford, California, United States
Show AbstractHeating consumes large amount of energy and is a primary source of greenhouse gas emission. Although energy-efficient buildings are developing quickly based on improving insulation and design, a large portion of energy continues to be wasted on heating empty space and nonhuman objects. Here, we demonstrate a system of personal thermal management using metallic nanowire-embedded cloth that can reduce this waste. The metallic nanowires form a conductive network that not only is highly thermal insulating because it reflects human body infrared radiation but also allows Joule heating to complement the passive insulation. The breathability and durability of the original cloth is not sacrificed because of the nanowires’ porous structure. This nanowire cloth can efficiently warm human bodies and save hundreds of watts per person as compared to traditional indoor heaters.
3:45 PM - SM2.9.05
Atomic Layer Deposition of Al2O3 to Improve Various Properties of Transparent Nanopaper
Thomas Schmitt 1 , Brandon Green 2 , Jonathan Kagan 2 , Erik Larmore 3 , Julia Downing 1 , Eddie Chang 2 , Parisa Davoodi 4 , Delena Ganey 2 , Sachi Khemka 5 , Hannah Russell 6 , Luke Travisano 2 , Jeannette Van Sickle 2 , Stacy Wang 7 , Liangbing Hu 1
1 Department of Materials Science and Engineering, University of Maryland, College Park, College Park, Maryland, United States, 2 Department of Mechanical Engineering, University of Maryland, College Park, College Park, Maryland, United States, 3 Department of Chemical Engineering, University of Maryland, College Park, College Park, Maryland, United States, 4 Department of Electrical and Computer Engineering, University of Maryland, College Park, College Park, Maryland, United States, 5 Robert H. Smith School of Business, University of Maryland, College Park, College Park, Maryland, United States, 6 Department of Chemistry , University of Maryland, College Park, College Park, Maryland, United States, 7 Department of Civil Engineering, University of Maryland, College Park, College Park, Maryland, United States
Show AbstractCellulose nanopaper (CNP) is a flexible, transparent, and renewable nanomaterial that is emerging as a replacement for plastic in various applications including printed “green” electronics and thin films. Its remarkable strength (historically σ ≥ 200 MPa), high transparency (T = 90%) and flexibility (radius of curvature ≤ 3mm) make it a promising material for the future. However, many of the potential applications require improvements in water stability, strength, and functionality. Atomic Layer Deposition (ALD) is a conformal deposition method that coats individual fibers through a two-stage process: first introducing a metal-organic precursor followed by an oxidant. ALD has been studied on cellulose aerogels and fibers on silicon substrates for various applications including oil separation from water, has not been performed on CNP yet. We demonstrate the use of ALD of aluminum oxide (Al2O3) on transparent nanopaper to increase the strength, water resistance, insulating properties, fire resistance, and functionality. Transparency measurements are performed using UV-Vis spectroscopy to verify that transparency, a key optical property of the material, is unaltered. Tensile testing, fire retardant testing, contact angle measurements, and four-point probe characterization of carbon nanotube coatings are used to indicate the effect of ALD on material parameters, which will be relevant for future device design and nanomanufacturing.
SM2.10: Advances in Fibers and Textiles III
Session Chairs
Alexander Gumennik
Guangming Tao
Thursday PM, April 20, 2017
PCC North, 100 Level, Room 122 A
5:00 PM - SM2.10.02
Bicomponent Nonwoven Fabrics as a Substrate for Mass-Production of Polymeric Microspheres
Felix Tan 1 , Joshua Kaufman 1 , Ayman Abouraddy 1
1 CREOL, The College of Optics & Photonics, University of Central Florida, Orlando, Florida, United States
Show AbstractBicomponent polymeric fibers, or fibers consisting of two distinct continuous material phases, have existed as commercial products since the 1960s. In the intervening time since, the number of manufacturers and applications for these fibers has increased dramatically. Fabrication of these fibers involves the co-extrusion of the two (or more) materials in a melt state from a spinneret, typically fed by screw extruders. There has been extensive work modeling and characterizing the fluid stability of these multimaterial spinning processes, predominantly motivated so as to mitigate adverse effects during processing [1].
However, there has been recent work in the field of multimaterial fibers whereby fluid instabilities are harnessed and controlled to produce uniformly sized, functionalized, and structured spheres [2]. They have applications in many fields, from paints and coatings to cosmetics and biomedical technologies [3]. Although the previous work was reported using thermal drawing as the fiber fabrication methodology, we show here that specialized fiber extrusion spinning machines can produce in-fiber spheres as well. Additionally, whereas thermal drawing is an inherently batch-scale process, fiber spinning is a continuous-scale production method with throughput capacities on the order of metric tons of resin per hour on a single machine.
We present here a working laboratory-scale model of a polymeric microsphere production process based on bicomponent, melt-blown nonwoven fabrics—an extension of previous work involving spun filaments [4]. The motivation for transitioning to nonwovens is the smaller fiber diameters produced without the need for large take-up (winding) speeds. It was previously shown that the amount of time required for the fluid instability to manifest and form spheres scales with the initial diameter of the core prior to break-up. Thus, in contrast to the minutes typically required to induce break-up in mm-scale fibers, we show that the required time is reduced to seconds for nonwovens in which typical fiber diameters are less than tens of microns. We present the results from producing homogeneous and composite microspheres, as well as discussing the possibility of more complex sphere geometries and functionalities.
[1] S. Kase and T. Matsuo, “Studies on melt spinning: fundamental equations on dynamics of melt spinning.” J. of Polymer Sci. 3 2541- (1965)
[2] J. J. Kaufman, G. Tao, S. Shabahang, E.-H. Banaei, D. S. Deng, X. Liang, S. G. Johnson, Y. Fink, and A. F. Abouraddy, “Structured spheres generated by an in-fibre fluid instability,” Nature 487, 463 (2012).
[3] J. J. Kaufman, R. Ottman, G. Tao, S. Shabahang, E.-H. Banaei, X. Liang, S. G. Johnson, Y. Fink, R. Chakrabarti, and A. F. Abouraddy, “In-fiber production of polymeric particles for biosensing and encapsulation,” Proc. Natl. Acad. Science (USA) 110, 15549 (2013).
[4] J. J. Kaufman, F. A. Tan, et al. To be submitted (2016)
5:15 PM - SM2.10.04
Highly Elastic Hydrogen-Bonded Polymer Complex Fiber
Shuguang Yang 1
1 State Key Laboratory for Modification of Chemical Fibers and Polymer Materials & Center for Advanced Low-Dimension Materials, Donghua University, Shanghai China
Show AbstractElastomers and highly elastic materials are essential to human life. The polymeric materials that can be used as elastomers should have flexible polymer chains, weak abilities for crystallization, relatively low glass transition temperatures, and mechanisms for cross-linking. Polybutadiene has flexible chain, but without vulcanization it is gummy, easy for oxidation and does not show resiliencies. Polysiloxane has pliable chain and the cross-linking of siloxane elastomers is obtained by co-hydrolysis of dichlorosilanes with alkyl-trichlorosilanes. Polyurethane is composed of soft and hard segments. The soft segments make the polymer show a high elongation while hard segments are hydrogen-bonded tie-points which ensure the recovery force. Low-dimensional elastic materials, such as fibers and thin films, are essential for developing the flexible electronics and intelligent wearable products. Traditional elastomers, such as natural rubber and polyurethane, are exploiting to make functional flexible fibers and films.
In this talk a new elastic fiber that is made from the hydrogen-bonded polymer complex of poly(acrylic acid) (PAA) and polyethylene oxide (PEO). First, a spinnable fluid is obtained by restricting hydrogen bonds, and then it is extruded through a spinneret into a coagulation bath where hydrogen bonds are built to induce fiber formation. PAA is an amorphous polymer and its glass transition temperature is around 100 °C. PEO has flexible chain and relatively low glass transition temperature, but PEO is easy to crystalize. Neither PAA nor PEO shows elastic behavior under ambient conditions. However through hydrogen-bonding complexation, the PAA/PEO system shows elastic behavior. PAA/PEO fiber shows excellent elastic behavior and can be drawn to more than 12 times of its original length without breaking, which is much higher than Spandex fiber or natural rubber fiber. In the fiber PAA and PEO are miscible in molecular level. Dynamic hydrogen bonding between PAA and PEO restricts the crystallization of PEO, retains flexibility of polymer chains, and also provides recovery forces when removing stress.
5:30 PM - SM2.10.05
Engineering Bacterial Cellulose Nanocomposites
Anna Roig 1 , Muling Zeng 1 , Deyaa Youssef 1 , Sebastia Parets 1 , Judit Fuentes 1 , Jordi Floriach 1 , Anna May-Masnou 1 , Anna Laromaine 1
1 , Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Bellaterra Spain
Show AbstractIndustries, governments and consumers increasingly request exploring greener, sustainable and natural resources for the fabrication of advanced complex materials. Cellulose constitutes an almost inexhaustible biopolymer, being the most abundant renewable polysaccharide produced in the biosphere. Although cellulose is predominantly obtained from plants, it can also be synthesized by bacteria, algae and fungi. In particular, bacterial cellulose (BC) produced by microbial fermentation has the same molecular formula as plant-derived cellulose but, in contrast, is a pure biopolymer that exhibits a high degree of polymerization and crystallinity. Importantly, BC does not contain lignin and hemicellulose, two non-degradable components and potential sources of toxicity present in plant-derived cellulose. BC is characterized by a three-dimensional architecture of cellulose fibers forming an interconnected open porous network. BC also has high porosity, transparency in the UV-NIR and a high water holding capacity. Moreover, a very unique characteristic of BC is the possibility to impact on its micro(nano)structuration and shape during the bacterial synthesis. Thus, the biosynthesis of cellulose offers to materials scientists a model biopolymer to study structure, topography and new bottom-up approaches to fabricate nanocomposites.
I will present the production and characterization of cellulose films and the impact that the film drying method has on its microstructure, porosity, wettability, transparency and mechanical properties. I will also present potential strategies to develop value-added engineered nanocomposites, such as magnetic paper, by anchoring inorganic nanocrystals on the BC fibers. These new bacterial cellulose nanocomposites will provide the proof of concept for devices or products.
Zeng et al. Journal of Materials Chemistry C 2 (2014) 6312-6318 DOI: 10.1039/c4tc00787e,
Zeng et al. Cellulose (2014) 21 4455–4469 DOI 10.1007/s10570-014-0408-y
5:45 PM - SM2.10.06
Textile Based Temperature Sensors—Fabrication, Characterization and Applications
Qiao Li 1 , Xin Ding 1 , Lina Zhang 1
1 , Donghua University, Shanghai China
Show AbstractTemperature varies both spatially and temporally in an effort to monitor physiological activities. Accurate and real-time measurement of localized temperature changes in soft tissue regardless of large-scale motion is crucial to understand thermal phenomena of homeostasis, to monitor health diagnostics, and further to offer possibilities of building a smart medical and healthcare system.
Many efforts have been made in soft and biocompatible temperature sensors. One approach is the MEMS based technology with polyimide, silicone or fabric as substrates to realize the flexibility of the temperature sensors. The other method is dependent on the functional materials. This paper focuses on temperature sensors in textiles and demonstrates the fabrication, characterization and applications of the textile-based temperature sensors.