Hydrophobic Ionic Conductive Elastomer with Heterogeneous Structure for Underwater Shock-Resistant Sensing

Abstract

It is a significant challenge to flexible wearable sensors that incur unstable output signals and malfunction because of omnipresent low-frequency vibrations. Because their design in terms of molecular friction is almost the opposite of the elasticity of the material, current sensing soft materials possess adequate elasticity but inadequate damping vibration. In contrast, using highly damaging materials for sensing is challenging due to their substantial hysteresis. Herein, a highly self-damping ionic elastomer with a heterogeneous two-phase structure is introduced by the one-step photopolymerization of fluorinated monomers and hydrophobic lauryl methacrylate (LMA). The distinct self-assembly behavior between fluorinated contents makes the occurrence of phase separation easier and thus decouples the damping and elastic functions into two different phases. This unique design overcomes the long-standing contradictions in the damping and elasticity of conventional gel materials. Thus, the optimal ionic elastomer of HIE-43 mol % achieves high stretchability, conductivity, elastic recovery, strain-stiffening, underwater adhesion, and high loss factors (tan δ > 1). Finally, reliable human motion sensing and underwater communication could be achieved with the ability of shock resistance and noise interference resistance. This study opens the door for the development of self-damping flexible conductive materials with robust sensing and protective applications.