Preparation of rGO/Cu NPs Cotton Sensor with a Three-Dimensional Conductive Network Structure for Efficient Strain Sensing Performance via Co-impregnation One-Bath Reduction Method

Abstract

Flexible electronic devices such as wearable strain sensors have attracted great attention in health monitoring systems. However, there are numerous challenges associated with the practical application of flexible strain sensors, including insufficient sensitivity, poor durability and stability, high manufacturing costs, complex signal processing, and integration issues. This study employed a straightforward and cost-effective co-impregnation one-bath reduction process to prepare a flexible strain sensor with high sensitivity, good responsiveness, and stability. Silane coupling agent KH-560 was employed for the modification of cotton knitted fabric, thereby enhancing the bonding strength between the cotton and reduced graphene oxide (rGO)/copper nanoparticles (Cu NPs). The rGO and Cu NPs were composited and loaded onto the surface of the modified cotton, with Cu NPs serving as connection points that adhere between the rGO surface and sheets, thereby forming a unique three-dimensional conductive network structure on the cotton. The fabrication of the rGO/Cu NPs/cotton sensor was optimized through single-factor and orthogonal experiments, with the objective of improving its sensitivity and stability. The rGO/Cu NPs/cotton sensor shows effective strain sensing for tensile strains ranging from 0 to 15% in both the horizontal and vertical directions, exhibiting high responsiveness at stretching speeds of 10–50 mm/min and maintaining stability after 100 cycles. Moreover, the rGO/Cu NPs/cotton sensor is capable of accurately detecting the degree of curvature of different joints during human movement and also exhibits a robust response to facial muscle movements.