In-depth analysis of mechanical and electrical responses of PDMS/MWCNT micro-composite films under cyclic loading conditions

This study has comprehensively examined the variations in the mechanical and electrical properties of PDMS/MWCNT micro-composite (PMMC) films under cyclic tensile loading. While previous studies have primarily focused on the electrical performance of wearable sensors, it is essential that wearable sensors need to meet both electrical characteristics and mechanical reliability throughout their designed operational lifespan. We conducted cyclic tensile tests for PMMC films with different MWCNT mass fractions of 3-wt%, 4-wt%, and 5-wt% and obtained cyclic mechanical properties and electrical conductivity. Each PMMC film exhibited distinct stabilization trends in both mechanical and electrical responses under cyclic loading. Additionally, the stabilised cyclic hyperelastic material properties were defined from the test results to enable predicting structural behaviour of PMMC films using finite element analysis. The results of this study provide valuable insights into the material properties and mechanical/electrical responses under cyclic loads for the structural integrity assessment of wearable sensors employing PMMC films.