Elastic and Thermoreversible Iongels by Supramolecular PVA/Phenol Interactions

Iongels have attracted much attention over the years as ion‐conducting soft materials for applications in several technologies including stimuli‐responsive drug release and flexible (bio)electronics. Nowadays, iongels with additional functionalities such as electronic conductivity, self‐healing, thermo‐responsiveness, or biocompatibility are actively being searched for high demanding applications. In this work, a simple and rapid synthetic pathway to prepare elastic and thermoreversible iongels is presented. These iongels are prepared by supramolecular crosslinking between polyphenols biomolecules with a hydroxyl‐rich biocompatible polymer such as poly(vinyl alcohol) (PVA) in the presence of ionic liquids. Using this strategy, a variety of iongels are obtained by combining different plant‐derived polyphenol compounds (PhC) such as gallic acid, pyrogallol, and tannic acid with imidazolium‐based ionic liquids, namely 1‐ethyl‐3‐methylimidazolium dicyanamide and 1‐ethyl‐3‐methylimidazolium bromide. A suite of characterization tools is used to study the structural, morphological, mechanical, rheological, and thermal properties of the supramolecular iongels. These iongels can withstand large deformations (40% under compression) with full recovery, revealing reversible transitions from solid to liquid state between 87 and 125 °C. Finally, the polyphenol‐based thermoreversible iongels show appropriated properties for their potential application as printable electrolytes for bioelectronics. Hyperelastic and thermoreversible iongels are prepared by supramolecular crosslinking between a plant‐derived polyphenol and poly(vinyl alcohol) in the presence of imidazolium‐based ionic liquids. The proposed synthetic pathway is simple and rapid, leading to soft‐ionic materials with sol–gel transitions around 100 °C, which paves the way for their potential application as printable electrolytes for bioelectronics.