Conductive, sensing stable and mechanical robust silicone rubber composites for large-strain sensors

Conductive polymer composites (CPCs) with carbon nanotubes (CNTs) have exhibited desirable sensing capacities to external stimuli. In this study, it is found that poor dispersion of single-wall CNTs gives rise to low mechanical strength and unsteady responsive signal outputs of CPCs as strain sensing materials. With attempt to solve this problem, we prepare the conductive silicone rubber composites with hybrid CNT masterbatch and carbon black (CB) fillers (CNT/CB composites) by drying mixing method. Hybrid CBs separate and loosen the entanglement of CNTs in CNT/CB composites which forms more conductive paths and better dispersion of CNTs than those only with single CNTs (CNT-composites). CNT/CB composite achieves a good conductivity, sufficient mechanical strength and high elasticity. In contrast with CNT-composite, its reproducibility of resistance responsivity was remarkably improved at strain cycles, which display stable sensing properties for mechanically strain sensor applications. Importantly, CNT/CB composites show outdoor usage robustness, including excellent salt-spray resistance, hot-humidity stability and a wide operation temperature range of -40 to +50 degrees C. It is believed that our work offers a simple approach to fabricate stable and flexible strain sensing materials, which is useful for sensor products.

Automated summary

The study shows that conductive silicone rubber composites with hybrid CNT masterbatch and carbon black fillers (CNT/CB composites) have better mechanical strength, elasticity, and conductivity compared to composites containing only single-wall CNTs. This improved dispersion of CNTs in CNT/CB composites leads to stable sensing properties, making them suitable for mechanically strain sensor applications. Additionally, CNT/CB composites demonstrate outdoor robustness and a wide operation temperature range, showing potential for use in sensor products.