High-performance amorphous carbon/PDMS flexible strain sensors by introducing low interfacial mismatch

Abstract

It is important and challenging to develop environment-tolerant stretchable strain sensors under some harsh environments. Here, amorphous carbon (a-C)/Polydimethylsiloxane (PDMS) sensors were fabricated with the direct-current magnetron sputtering technology, their sensing performances were optimized by adjusting the elastic mismatch between the top a-C film and used PDMS substrate, and their application under a simulated marine atmospheric environment was evaluated. The results showed that the combination of low stress a-C and low elastic modulus PDMS was favorable to improve the sensing performance, the optimal sensor exhibited the maximum gauge factor (GF) of 3026.9, large tensile strain range to 50 %, rapid response (loading delay time 92.3 ms and unloading delay time 24.6 ms), as well as high durability (>5000 cycles). After 120 h salt spray test, the sensor was quite stable and can detect various human movements with both high sensitivity and stability, such as wrist pulse, wrist bending, and finger bending. This work pioneers the elastic mismatch strategy for high-performance a-C/PDMS sensors and confirms their great potential in the practical applications under harsh environments.