Thermoresponsive microwrinkled hydrogel surfaces with modulated chemical composition

Smart wrinkled hydrogel patterns with modulated chemical composition and wrinkle characteristics (amplitude and period) were formed by taking advantage of surface instabilities using a simple, cost-affordable, and robust method. The microstructured surfaces were prepared by dip coating and were designed to be stimuli-responsive by introducing poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) in the initial feed. For this purpose, a silylated substrate surface serves as an anchor for the non-polymerized hydrogel molecules, thus forming a homogenous and reproducible coating. Once the film was achieved, the samples were exposed to vacuum and UV irradiation to form wrinkled patterns spontaneously. The response of the thermosensitive wrinkles reveals significant variations in the properties of the wrinkled films depending on the temperature. In addition to the simplicity, this deposition strategy allows the preparation of highly reproducible films using an easy-scalable methodology with potential interest for industrial applications.
The authors acknowledge the financial support given by FONDECYT Grant N◦ 1170209. J. Rodriguez-Hernandez acknowledges financial support from Ministerio de Ciencia, Innovación y Universidades (Project RTI2018-096328-B-I00). Finally, this study was funded by VRAC Grant Number LPR20-03 and L318-02 of Universidad Tecnológica Metropolitana.