Hydrogen-Bonding-Driven Tough Ionogels Containing Spiropyran-Functionalized Ionic Liquids

Abstract

Smart control of the physicochemical properties of ionogels is paramount for on-demand applications. However, the development of mechanically robust smart ionogels prepared from stimuli-responsive ionic liquids (ILs) still remains a considerable challenge. Here, we report light-responsive tough ionogels driven by hydrogen bonding between spiropyran-functionalized ILs and poly(ethyl acrylate)-based double networks. The designed ionogel possesses excellent mechanical properties (moderate elastic modulus of ∼524 kPa, large stretchability of ∼2880% strain, and high toughness of ∼46.4 MJ m–3). Moreover, the ionogel exhibits rapid and obvious color changes upon UV- and visible-light irradiation, resulting from the reversible structural transformation between spiropyran and merocyanine forms of the IL dispersant. This feature enables reversible photopatterning on the ionogel that can be written and erased upon photoirradiation. We envision that the light-responsive tough ionogels could have potential applications in optical data storage and photoswitchable devices.