Advances in rubber-based piezoresistive flexible strain sensors

Abstract

With the rapid development of science and technology, flexible strain sensors have attracted widespread attention in various fields such as electronic skin and healthcare due to their excellent sensitivity. Among them, rubber materials are considered ideal for stretchable electronic devices due to their flexibility. This paper primarily introduces rubber-based flexible strain sensors, outlining their sensing mechanisms and key performance parameters. This paper innovatively selects rubber materials with different characteristics as flexible substrates. Through systematic experimental comparisons and theoretical analyses, it deeply explores the influence and advantages of different rubber substrates on key performance indicators such as the sensitivity, working range, and long-term stability of piezoresistive flexible strain sensors, and proposes targeted optimization strategies. Rubber is mainly categorized into natural rubber and synthetic rubber. Natural rubber, owing to its good elasticity, low cost, and good biocompatibility, has promoted the green development of electronic devices. For instance, the NR/N-BP/NR sandwich strain sensor exhibits ultra-high sensitivity (GF = 2280) and a wide operating range of up to 500 %. Synthetic rubbers, including silicone rubber, nitrile butadiene rubber, and styrene butadiene rubber, have demonstrated great potential in the fabrication of flexible strain sensors due to their resistance to chemicals, heat, and wear. For example, the bilayer strain sensor fabricated from CB and PDMS demonstrates long-term stability over 10,000 loading-unloading cycle tests. The specific applications of these sensors in fields such as human motion detection, health management, and human-machine interfaces are also reviewed. Finally, the challenges faced by rubber-based flexible strain sensors are discussed, and prospects for enhancing their sensing performance and durability under extreme environmental conditions are anticipated.