Graphene-based flexible temperature/pressure dual-mode sensor as a finger sleeve for robotic arms

The design of sensors with multiple sensing functions has become a new challenge to meet the measurement of multiple stimulus signals in people's productive lives. In this article, a sandwich type dual-mode flexible sensor is designed to achieve simultaneous detection of pressure and temperature by constructing different sensing model structures. The dual-mode flexible sensor essentially comprises graphene, melamine sponge and Ag nanoparticle ink. Graphene is coated on the melamine sponge to form a 3D conductive sponge using the dip coating method, while Ag nanoparticle ink is printed on PET to form a serpentine electrode through inkjet printing technology. The sensor has high sensitivity (1.937 × 10−4 Pa−1, R2 = 0.953), a wide operating range (from 0 to 40 kPa), speedy response time (248 ms) and remarkable stability in pressure measurement. It also shows high linearity (TCR = 1.035 × 10−3 °C−1, R2 = 0.987) from 10 to 60 °C and is pressure insensitive in temperature measurement. Experimental results show that the different sensing mechanisms and structural configurations allow the sensors to detect pressure and temperature signals independently or simultaneously without signal coupling. The fabricated sensor has applications in health monitoring, rehabilitation therapy, human-machine interaction and intelligent prosthetics.