Highly Flexible and Sensitive Pressure Sensor: Fabrication of Porous PDMS/Graphene Composite via Laser Thermoforming

Abstract

Flexible pressure sensors employing porous polymer materials are renowned for their superior sensing capabilities, attributed to the inherently low stiffness of porous polymers. The practical utilization of such sensors hinges on the development of a straightforward, cost-effective, and patternable method for preparing porous polymer materials. In this research, a novel laser thermoforming process is introduced to craft a porous Polydimethylsiloxane (PDMS) film, leveraging carbon black (CB) as an endothermic agent and glucose as a porogen. The resulting porous PDMS film serves as the foundation for a remarkably sensitive flexible piezoresistive sensor. Owing to the inherent flexibility endowed by the porous structure, the porous PDMS-based pressure sensor achieves a remarkable sensitivity of 109.4 kPa⁻¹ within 0–200 Pa, an effective measurement span of 0–100 kPa, rapid response and recovery times of 79 and 55 ms, and impressive stability over 5000 cycles. The sensor's utility extends to applications such as human pulse monitoring, Morse coding, and robot claw sensing, underscoring its promise in the realm of flexible electronics. In summary, the laser thermoforming process realizes the one-step, economical, and patternable preparation of porous polymer materials, and introduces a novel avenue for the realization of high-performance flexible sensors based on thermally cured porous polymers.