Fabrication of Self-Healable, Low-Temperature-Resistant, Conductive Polyionic Gel Strain Sensors and Construction of Poly(ionic liquid)-Based Superhydrophobic Coating

Abstract Composite gels have attracted attention in recent years in the fields of smart sensing and flexible wearable electronics. Easy damage, inability to self-heal, and freeze hardening at low temperatures are still the main issues that limit the development of gel sensors. In this work, multifunctional polyionic composite gel strain sensors were fabricated by combining poly(vinyl alcohol) (PVA) with hydrophobic imidazolium-type poly(ionic liquid) (P[VPI+][Tf2N–]). The mixed polymer solution realized spontaneous gelation at room temperature, and the gels exhibited self-healing, antifreezing, high stretchability, and conductivity, making them suitable for human joint motion monitoring and speech recognition at room or low temperatures. Moreover, through modification with silica nanoparticles and heptadecafluorodecyltrimethoxysilane, the nanocomposite coating of PVA/P[VPI+][Tf2N–] achieved superhydrophobicity (a static contact angle of 159.03°), displaying effective antifogging, antifouling, and self-cleaning properties. This work provides a universal approach to preparing multifunctional polymer composite materials based on poly(ionic liquids), which could be extended to other polymers.