Soft conductors show great promise in multifunctional sensor applications. However, both electronically and ionically conductive materials are often vulnerable during large deformation or at low temperatures, leading to reduced sensitivity, which is usually overlooked and remains an unaddressed challenge. In this work, we report a novel zwitterionic liquid polymer hydrogel with extraordinary mechanical versatility, high transparency and conductivity, and anti-freezing ability to overcome the above limitations. The conductive zwitterionic nanochannels formed by the zwitterionic liquid (ZIL) and methacrylate lysine (LysMA) endow the hydrogel with excellent conductivity and low-temperature tolerance. Furthermore, the hydrogel exhibited high transparency, remarkable stretchability (over 2000%), self-healing properties, high adhesiveness to diverse substrates and high conductivity, even at low temperatures (−40 °C). These attributes are advantageous for sensor applications. Owing to these outstanding properties, the hydrogel was evaluated for a skin sensor application, and the hydrogel-based sensor showed a gauge factor (GF) of up to 6.42 and 14.96 with and without LiCl, respectively. More importantly, this hydrogel exhibits high strain sensitivity over an extremely broad workable range with good stability and repeatability. In conclusion, the zwitterionic liquid-based electronic sensor with flexible, stretchable, self-healing and anti-freezing properties is a promising candidate for strain sensors and ionic skin for wearable electronic devices.

The introduction of ceramic fillers into a polymer matrix is an effective way to obtain dielectric nanocomposites with high energy storage density. However, the inorganic fillers are difficult to disperse evenly into the polymer matrix because of the poor compatibility, which stems from the large surface energy difference and the mismatch in dielectric constant between the fillers and polymer matrix. Polymer nanocomposites with high dielectric constant while maintaining high breakdown strength have great potential to achieve high energy storage density. In this work, poly(dodecafluoroheptyl methacrylate) terminated with a thiol end group (PDFMA-SH) was synthesized via a two-step process including Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization and subsequent aminolysis reaction. The polymer was then grafted into the surface of BaTiO₃ (BT) nanoparticles by a “thiol–ene” click reaction to reduce the surface energy of BT nanoparticles. A novel nanocomposite consisted of the core–shell structured PDFMA@BT hybrid nanoparticles and poly(vinylidene fluoride–chlorotrifluoroethylene) (P(VDF–CTFE)) matrix was prepared. The influence of the fluoropolymer shell on the dispersion of fillers, the compatibility between the fillers and polymer matrix, dielectric properties and breakdown strength were investigated systematically. The results indicate that the strong interfacial adhesion between the hybrid nanoparticles and P(VDF–CTFE) matrix makes the fillers uniformly dispersed in the polymer matrix. Meanwhile, the excellent compatibility between the two components is favorable for enhancing the breakdown strength and suppressing dielectric loss, providing a condition to prepare dielectric materials with high energy storage density.