Available on-demand - F.SM01.03.11
Rational Design of Bio-Inspired Nanowire Architectures for Preventing Marine Biofouling
Jing Wang1,Sudarat Lee1,Ashley Bielinski1,Kevin Meyer1,Abhishek Dhyani1,Alondra Ortiz-Ortiz1,Anish Tuteja1,Neil Dasgupta1
University of Michigan1
Biofouling has a negative impact on human health and economic development. In particular, biofilms in the marine environment grow easily, adhere strongly on most surfaces, and continuously generate adhesive proteins from the living organisms in the film. They cause increased fuel penalty, attenuation of sensor signals, and more . To overcome these challenges, several natural surfaces, including shark skin , crab eyes , and dragonfly wings , have shown reduced biofilm settlement, nucleation, and adhesion because of their micro- and nano- surface textures.
Inspired by natural surfaces, herein, we present the rational design and fabrication of ZnO/Al2O3 core-shell nanowire (NW) architectures to significantly reduce marine biofouling (algae: cyanobacteria and diatoms) and further suppress the biofilm formation by tuning the NW geometry (length, spacing, branching) and surface chemistry . Specifically, for hydrophilic NWs, we demonstrated algal fouling on NWs was only 40% of the fouling coverage on planar control surfaces when they were fully covered. These NWs outperform the surfaces with micrometer length-scale textures in marine fouling reduction under a multi-species fouling environment. Two mechanisms of the fouling reduction were summarized with geometric and mechanical effect of the NWs: (1) reduced effective settlement area, and (2) mechanical cell penetration. For superhydrophobic NWs, we demonstrated anti-biofouling performance for up to 22 days, which is one order of magnitude longer duration than what have been reported in the literature  under biofouling environment. A mass diffusion and thermodynamic model was developed to explain and predict the anti-fouling duration on NWs in the Cassie state. Furthermore, the nanowire surfaces are transparent across the visible spectrum, making them applicable to windows and oceanographic sensors. Through the rational control of surface nano-architectures, the coupled relationships between wettability, transparency, and anti-biofouling performance are identified. We envision that the insights gained from the work can be used to systematically design surfaces that reduce marine biofouling in various industrial settings.
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