Tactile imaging and distributed strain sensing in highly flexible carbon nanofiber/polyurethane nanocomposites

Highly flexible nanocomposites have tremendous potential as smart, self-sensing materials because their conductivity is inherently linked to their mechanical state. Herein, carbon nanofiber (CNF)/polyurethane (PU) nanocomposites are studied for tactile imaging and distributed strain sensing via electrical impedance tomography (EIT) by investigating the influence of filler volume fraction on microscale morphology, piezoresistive response while bonded to mechanically loaded substrates, and sensitivity to distributed strain. Load testing of the bonded sensor reveals that viscoelasticity and filler volume fraction profoundly affect the piezoresistive response. EIT is able to accurately capture and discern between multiple points of contact in each volume fraction with lower volume fractions being more sensitive thereby demonstrating the potential of utilizing tomographic methods for tactile imaging and distributed strain sensing in PU-based nanocomposites.