High-sensitivity porous PDMS sensor based on laser-etched pyramidal structure

In this paper, a flexible resistive pressure sensor of polydimethylsiloxane (PDMS) with porous pyramidal array structure is proposed to be prepared rapidly by laser etching. The porous doped PDMS was prepared by laser etching technique and continuous heat treatment to overcome the viscosity requirement of porous silica by traditional template method, reduce the preparation cost, and improve the practicality. Using the carbon-based filler material with high light absorption coefficient and low interfacial thermal resistance, the light absorption coefficient of MWCNTs has a significant role in laser etching, which has a significant effect on the depth of cut of the laser. In addition, the strain response of the porous PDMS sponge media layer under different external forces was simulated using finite element analysis (FEA). Its sensitivity is as high as 645 kPa⁻¹, with fast response of 26 ms and 32 ms, good hysteresis (0.78%), and strong stability in 5000 cycles. The ultra-high sensitivity is the key to make the flexible pressure sensor widely use in medical detection, which can be widely applied to heartbeat detection, gesture recognition, and real-time detection in healthcare.