Comparative analysis of micro patterned PDMS-based piezoresistive pressure sensors with multifunctional strain and health monitoring applications

Abstract

Flexible strain and pressure sensors are widely utilized for healthcare and wearable applications. But the majority of the sensors include sophisticated fabrication methodology, are less adaptable, expensive, and need to provide higher sensitivity. In this work, addressing these issues, we have investigated four different micropatterned Poly Dimethyl Siloxane (PDMS)-based device configurations to develop a cost-effective, high performance physical sensing form for both pressure and strain sensing. PDMS is poured into four different micropatterned molds, and the patterned surface of the PDMS is rendered conductive by the thermal evaporation of copper metal. Given the ease of fabrication and clean room-free approach, the optimized pressure sensor yields a sensitivity of 1.77 kPa−1 over the dynamic range of 100 N – 600 N and a response time of 0.31 s. Further, the PDMS-based pressure sensor is used for an ultrasensitive carotid arterial pulse and speech detection to demonstrate its real-time applications. When utilized as a strain sensor, the fabricated device exhibits a (GF) Gauge Factor of 22 and 0.2 s response time and could detect compressive and tensile strains ranging from 9.2–61.6 %. To illustrate its practicality, the PDMS-based strain sensor is also used for gesture detection. This excellent response of the fabricated sensor can be attributed to a piezoresistive working mechanism. The concept presented here paves the way for developing adaptive, low-cost, clean-room-free, simpler multipurpose sensors for medical applications and wearable consumer electronics by exploring different types of novel architectures with optimal performance.