Ionogel surface patterns fabricated by photodimerization-induced self-organized spatial reconstruction

Abstract

The fabrication of on-demand surface microstructures on ionic skins is critical for their applications, but conventional methods struggle to achieve high-fidelity, modulus-adjustable patterns in a single-step, non-destructive process. This text reports a photodimerization-driven self-organized strategy for spatially programmable surface reconstruction of ionic gels. By selectively irradiating a physically crosslinked anthracene-grafted polyvinyl alcohol (AnPVA)/ionic liquid network with ultraviolet (UV) light, anthracene photodimerization establishes a chemical gradient. These gradient drives directional migration of polymer chains from unexposed to exposed regions, resulting in spontaneous surface patterning and modulus modulation. Photomask-guided spatiotemporal control of UV exposure allows precise fabrication of diverse architectures with adjustable surface moduli and heights. Factors such as temperature, ionic liquid content, and material thickness can regulate polymer chains’ migration dynamics, enabling tailored pattern growth. The microstructure creates stress concentrations and depth modulus gradients that increase pressure sensitivity (up to 41-fold compared to the original) and durability. By integrating bottom-up self-organization with top-down spatial precision, this method does not rely on complex lithography, offering a scalable, non-contact route to customize ionic skins for bio-inspired sensing, adaptive soft robotics, and multifunctional human-machine interfaces.