Investigation of Lightweight and Flexible Carbon Nanofiber/Poly Dimethylsiloxane Nanocomposite Sponge for Piezoresistive Sensor Application

In this paper, highly flexible and compressible piezoresistive nanocomposites consisting of carbon nanofibers (CNFs) and polydimethylsiloxane (PDMS) are developed for sensing applications. Porous PDMS with a porosity of 74.7% is manufactured using sugar templates, and CNFs are infiltrated into the porous structures to tailor the material's electrical resistivity. The highly flexible pressure sensors show piezoresistive characteristics up to 70% compressive strains due to the conductive CNF network and the porous microstructures of the fabricated nanocomposites. The reorganization of CNF conductive network is characterized using in-situ micromechanical tests within a scanning electron microscope, validating the piezoresistive sensing mechanism. The sensing performance under various maximum applied strains, elevated load rates, and long-term repeatability is characterized. The developed porous nanocomposite sponge is employed as a tactile wearable sensor.