Formation of responsive hierarchical wrinkled patterns on hydrogel films via multi-step methodology

In this article, a simple protocol based on a multi-step methodology is used to form flat, first-generation (G1) or second-generation (G2) wrinkled patterns. Different concentrations of DMAEMA were used to synthesize hydrogel films. The multi-step method used to form the wrinkled pattern involves vacuum, argon plasma, and UV exposure. This methodology allows creating different morphologies, which are intimately related to both the kind of treatment as well as the order employed in each case. The G1 and G2 patterns involve three essential steps. First, water removal via vacuum, generating a deswelling gradient in the films triggering the formation of a G1 pattern on top. Secondly, a frontal vitrification process was induced by argon plasma, which generates a rigid top layer, thus triggering the formation of a G2 pattern. Finally, UV irradiation for fixing the pattern. From these, we obtained the roughness, area increase percentage, undulation wavelength, and amplitude.