Photodimerization Induced Hierarchical and Asymmetric Iontronic Micropatterns

Abstract Micropatterning various ions-based modality materials offers compelling advantages for their functionality enhancement in iontronic pressure sensing, piezoionic mechanoreception, and skin-interfaced electrode adhesion. However, most existing patterning techniques for iontronic materials suffer from low flexibility and limited modulation capability. Herein, we propose a facile and robust method to fabricate hierarchical and asymmetrical iontronic micropatterns (denoted as HAIM) through programmed regulation of the internal stress distribution and the local ionic migration among an iontronic host. The resultant primary patterns and secondary wrinkles with arbitrary regulated morphology and region-dependent ionic electrical performance can be readily made upon iontronic host via localized photodimerization of anthracene-functionalized ionic liquid copolymer (denoted as An-PIL) and subsequently vapor oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT). By controlling the local secretion of room temperature ionic liquid (denoted as IL) droplets and subsequently doping into the resultant PEDOT, it was possible to modulate the surface conductivity as well as the potential gradients of the HAIM. Taking the spatiotemporal advantages of light, heat, and vapor, the morphology and electrical performance of HAIM can be modulated by programmed exposure with photomask and polymerization time. Besides, based on the piezoionic effect within the resultant IL-doped PEDOT, the HAIM can serve as a scalable iontronic potential generator. The successful synthesis of these fascinating micropatterns may provide new insights into the development of patterned iontronic materials in a flexible, programmable, and functionally adaptive form.