Strain and damage-sensing performance of biocompatible smart CNT/UHMWPE nanocomposites

Herein, we report strain- and damage-sensing performance of biocompatible smart CNT/UHMWPE nanocomposites for the first time. CNT/UHMWPE nanocomposites are fabricated by solution mixing followed by compression molding. The surface morphology, microstructural properties, thermal decomposition and stability, glass transition temperature and thermal conductivity of the nanocomposites are characterized. The degree of crystallinity of CNT/UHMWPE nanocomposites is found to have a maximum value of 52% at 0.1 wt% CNT loading. The degree of crystallinity influences the mechanical properties of the CNT/UHMWPE nanocomposites. The electrical percolation threshold is achieved at 0.05 wt% of CNT and it follows a two dimensional conductive network according to percolation theory. The piezoresistive response of CNT/UHMWPE nanocomposites is demonstrated with a gauge factor of ~2.0 in linear elastic regime and that in the range of 3.8-96.0 in inelastic regimes for 0.05 wt% of CNT loading. A simple theoretical model is also developed to predict the resistivity evolution in both elastic and inelastic regimes. High sensitivity of CNT/UHMWPE nanocomposites coupled with linear piezoresistive response up to 100% strain demonstrates their potential for application in artificial implants as a self-sensing material.