Dec 4, 2024
4:30pm - 4:45pm
Sheraton, Third Floor, Dalton
Eric Chia1,Jayesh Sonawane1,Derek Lovley1,Stephen Nonnenmann1
University of Massachusetts Amherst1
Eric Chia1,Jayesh Sonawane1,Derek Lovley1,Stephen Nonnenmann1
University of Massachusetts Amherst1
Electrically conductive protein nanowires (e-PNs) synthesized via expression of the <i>Geobacter sulfurreducens</i> pilin gene in aerobically grown <i>Escherichia coli</i> strain show great promise in applications including sensors, bio-memristors, and electrical power generation. Most studies have focused on the electrical properties and performance of e-PNs, whereas the mechanical properties of e-PNs have been largely unexplored. Therefore, the elastic properties of individual e-PNs and their effects as nanocomposite fillers was measured with atomic force microscopy (AFM) nanoindentation. Fast force mapping (FFM) revealed that individual e-PNs exhibited an elastic modulus of 2.13±1.61 GPa, in reasonable agreement with previous theoretical calculations for microbial type IV pilus filaments. When e-PNs were integrated into a polydimethylsiloxane (PDMS) elastomer matrix the elastic modulus of e-PNs/PDMS nanocomposites displayed filler loaded-dependent trends similar to other polymer-based composites with nanowire fillers. Amplitude modulation, frequency modulation (AM-FM) bimodal imaging yielded an elastic modulus for pristine PDMS of 159.87±7.13 MPa. The elastic modulus of the e-PN/PDMS composites were highly tunable over a range of 1 – 10 wt% e-PNs, highlighted by a ~ 51% increase at 10 wt% (241.70±11.91 MPa). The correlation between e-PN weight percentage and the Young’s modulus of e-PN/PDMS composites aligns with percolation theory. Evaluation of the electrical properties of the e-PN/PDMS composites revealed a threshold behavior at approximately 5 wt% e-PNs. This study demonstrates concentration-dependent elastic and electrical properties of e-PN/PDMS nanocomposites, making them a strong candidate for conductive elastomers in a variety of functional devices.