4:30 PM - BI02.03.02
A Sustainable Future for Materials Science and Engineering—Enabling Scalable Manufacturing of Polymer Nanocomposites and Addressing Underrepresentation of Women in the Field
Cecile Chazot1,John Hart1
Massachusetts Institute of Technology1
Polymer nanocomposites have been proposed as next-generation lightweight structural materials for applications ranging from aerospace to automotive and sports equipment. However, their processing often requires high temperatures for hours (or sometimes days), contributing to their energy footprint. Additionally nanocomposite manufacturing techniques, such as dispersion of nanofillers in polymer solutions and resin infusion in nanoporous assemblies, often result in composite systems with heterogeneous morphologies and therefore reduced mechanical properties. We present a scalable, low-temperature nanocomposite manufacturing method called in-situ interfacial polymerization (ISIP), which is based on interfacial polycondensation of high-performance polymers in nanoporous assemblies. For example, we demonstrate that dense carbon nanotube (CNT)-polymer composites can be obtained by ISIP within CNT networks. Uniform aramid-CNT composite sheets obtained by this method have a Young’s modulus of 31 GPa and a tensile strength of 776 MPa, which is a two-fold increase compared to the pristine CNT sheets. We also present how ISIP can be extended to a broad range of polymers and matrices including nanofiber mats and 3D printed lattices. A macrokinetics model describing the simultaneous fluid flow and polymerization reaction is used to predict final composite morphology and performance. We also demonstrate the implementation of ISIP as a roll-to-roll process, where the nanoporous substrate is continuously drawn through the series of liquid immersion steps to produce the final composite fiber.
We also share the personal experience of a woman in STEM and Materials Science and Engineering (MSE) from technical high school in France to graduate school in the United States. While women represent 44% of the total workforce in the US, they constitute 39% of materials scientists and chemists, and only 16% of materials engineers.[3,4] Notably, the proportion of women decreases with increasing degree level in higher education in MSE in both France and the US. We will put the underrepresentation at the highest level of the field in relation with the social psychology topic of stereotype threat: a type of social identity threat that occurs when one fears being judged in terms of a group-based stereotype.[5,6] Last, we will discuss current ongoing initiatives at MIT targeted at mitigating stereotype threat and reducing these inequalities in the laboratory and the classroom.
 C. A. C. Chazot and A. J. Hart, “Understanding and control of interactions between carbon nanotubes and polymers for manufacturing of high-performance composite materials,” Compos. Sci. Technol., vol. 183, p. 107795, Oct. 2019, doi: 10.1016/J.COMPSCITECH.2019.107795.
 C. A. C. Chazot, C. K. Jons, and A. J. Hart, “In Situ Interfacial Polymerization: A Technique for Rapid Formation of Highly Loaded Carbon Nanotube-Polymer Composites,” Adv. Funct. Mater., vol. 30, no. 52, p. 2005499, Dec. 2020, doi: 10.1002/adfm.202005499.
 “A Report on the Workshop on Gender Equity in Materials Science and Engineering,” College Park, Maryland, 2008. Accessed: Jun. 15, 2021. [Online]. Available: https://www.nsf.gov/mps/dmr/BroadeningPresentations/gewreport.pdf.
 C. Corbett and C. Hill, Solving the equation: The Variables for Women’s Success in Engineering and Computing. Washington, DC: American Association for University Women, 2015.
 M. C. Murphy, C. M. Steele, and J. J. Gross, “Signaling threat: How situational cues affect women in math, science, and engineering settings,” Psychol. Sci., vol. 18, no. 10, pp. 879–885, Oct. 2007, doi: 10.1111/j.1467-9280.2007.01995.x.
 S. J. Spencer, C. M. Steele, and D. M. Quinn, “Stereotype Threat and Women’s Math Performance,” J. Exp. Soc. Psychol., vol. 35, no. 1, pp. 4–28, Jan. 1999, doi: 10.1006/jesp.1998.1373.