Liquid metal circuit based magnetoresistive strain sensor with discriminating magnetic and mechanical sensitivity

Abstract This work reported a stretchable, magneto-sensitive and discriminative strain sensor consisting of liquid metal (LM) as the electronic circuit and carbonyl iron particles (CIPs)/polydimethylsiloxane (PDMS) composite as the packaging material (LME-MRE). Due to the good elasticity of PDMS matrix and unique magnetic interactions among CIPs, the LME-MRE sensor was both sensitive to the external mechanical and magnetic stimuli. Moreover, owing to the fluidic nature of liquid metal, LME-MRE sensor also exhibited good electrically healing capability. The relative resistance variation ( Δ R / R 0 ) of LME-MRE sensor reached as high as 1038% under 40% compressive strain. The electrical properties of LME-MRE sensor also remarkably changed under cyclic stretching and bending. Moreover, a 7.4% decrement of resistance was achieved under applying a 300 mT magnetic field to LME-MRE sensor. Importantly, the magnetic and mechanical stimuli could be discriminated by LME-MRE sensor and a possible mechanism was proposed to describe the mechanic-electric-magnetic sensing characteristics. Finally, a LME-MRE sensor array is developed for the detection of both compressive force and magnetic field, demonstrating a broad promising in future intelligent devices, like artificial electronic skins and soft robotics.