Porous Microstructure-Assisted Flexible and Highly Sensitive Polymer Piezoresistive Pressure Sensor

Flexible and wearable pressure sensors are gaining attention due to their widespread applications in biomedical, intelligent, and smart systems. However, developing highly sensitive sensors for low pressures and wide ranges is still a challenge. In this direction, a flexible PDMS-based pressure sensor is presented, having hemispherical microstructures to achieve high sensitivity and operation range. Several experiments with various dimensions have demonstrated that the sensor with microstructures of radii 100 mu m on a 0.5 mm-thick substrate shows optimum performance for a low-pressure range of less than 6 kPa. Further, a finite-element method-based simulation has illustrated improvement in the sensor response with the decrease in substrate thickness. In practice, a very thin film of the substrate is not suitable for detecting a wide range of pressure. The presence of microstructures, however, improves the performance. Adding porosity to the substrate further elevates the sensitivity to 9.51 kPa(-1) for a low-pressure range of less than 10 kPa. Even for medium (30-70 kPa) and high-pressure ranges (40-120 kPa), the sensitivities of the sensor proposed are as high as 0.045 and 0.17 kPa(-1), respectively. The proposed sensors show at least an order improvement of sensitivities compared with the prior arts.

Automated summary

This study presents a flexible PDMS-based pressure sensor with hemispherical microstructures, achieving high sensitivity and operation range. Experiments and simulations show that decreasing the substrate thickness and adding porosity can further improve the sensor performance.