Gradient Pore Structured Ppy/Pdms Conductive Sponge for Flexible Strain Sensor

Flexible strain sensors based on porous conductive composites have potential applications in electronic skin, healthcare due to their pressure-responsive electrical conductivity. However, simultaneously enhancing sensitivity and expanding the working range remains a formidable challenge. In this paper, we present a Ppy/PDMS porous conductive sponge with gradient porous structures fabricated using the emulsion ice template method. This technique effectively eliminates the issues associated with template residues, thereby simplifying the process, reducing costs, and promoting environmental sustainability. Herein, different pore sizes offer distinct performance advantages for the Ppy/PDMS sensor. In this study, the distinct performance advantages of the Ppy/PDMS sensor are attributed to different pore sizes. The presence of large pores in the gradient porous structure, characterized by a low modulus, effectively facilitates the detection of relatively low pressure. Simultaneously, small pores with a high modulus provide robust mechanical strength, ultimately enhancing the working range. The inherent characteristics of our sensor enable it to possess a wide sensing range spanning from 0% to 70%, high sensitivity (S = 31.4), and exceptional durability even after undergoing 3000 compression-release cycles. Additionally, the sensor demonstrates a diverse range of applications, encompassing pressure/weight monitoring, real-time measurement of human pulse waves, and joint motion detection. Furthermore, an array of our sensors possesses the capability to collect spatiotemporally resolved signals for the purpose of monitoring and analyzing intricate actions.