Synergy of Single‐ion Conductive and Thermo‐responsive Copolymer Hydrogels Achieving Anti‐Arrhenius Ionic Conductivity

Artificial intelligence sensations have aroused scientific interest from electronic conductors to bio‐inspired ionic conductors. The conductivity of electrons decreases with increasing temperature, while the ionic conductivity agrees with an Arrhenius equation or a modified Vogel–Tammann–Fulcher (VTF) equation. Herein, thermo‐responsive poly(N‐isopropyl amide) (PNIPAm) and single‐ion‐conducting poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic lithium salt) (PAMPSLi) were copolymerized via a facile radical polymerization to demonstrate a very intriguing anti‐Arrhenius ionic conductivity behaviour during thermally induced volume‐phase transition. These smart hydrogels presented very promising scaffolds for architecting flexible, wearable or advanced functional ionic devices. A smart hydrogel was designed by combing thermo‐responsive poly(N‐isopropyl amide) with single‐ion conductive poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic lithium salt). The hydrogel demonstrates anti‐Arrhenius ionic conductivity behaviour during the thermally induced phase transition. The hydrogel‐based device displays a constant resistance value of 60 Ω (30 °C) to about 93 Ω (60 °C) in heating–cooling cycles, indicative of fast‐response and excellent reliability.