Controlling the particle size of nano-silica to regulate the coupling between conductive silicone rubber interfaces and sensing stability: experiments and molecular simulations

Conductive polymer composites have been widely used in flexible electronics and smart sensing due to their strain-induced resistance changes. However, during practical applications, their resistance signals often exhibit a shoulder peak effect, resulting in signal instability and reduced sensing accuracy and reproducibility. In this study, conductive silicone rubber(SR) composites (PSR) were engineered with improved control the conductive network structure by adjusting the particle size of nano-silica (NSD). When the NSD particle size was 100 nm (PSR-100), a steric hindrance structure formed within the matrix, restricting the slippage and rearrangement of graphene (GR) along the SR molecular chains. This improved the interfacial coupling stability between GR and SR, reducing the resistance hysteresis area by 69.78% and effectively eliminating the shoulder peak effect. The underlying mechanisms of shoulder peak effect generation and suppression were elucidated through both experimental analysis and molecular dynamics (MD) simulations. Furthermore, PSR-100 demonstrated superior electromechanical performance, with tensile strength and elongation at break increased by 26.87% and 12.23%, respectively. It also exhibited a high gauge factor (GF) of 58,354.21 and a rapid response time of 200 ms. These findings offer valuable theoretical insights and technical strategies for developing high-performance flexible electronics and expanding their applications in smart monitoring and wearable technologies.