Direct grafting of microwrinkled hydrogels by atmospheric-pressure plasma polymerization: Going simple and environmentally friendly

The simple, direct fabrication of pH-responsive hydrogel coatings with microstructured wrinkles from a monomer mixture containing 2-hydroxyethyl methacrylate and 2-(diethylamino)ethyl methacrylate, grafted on silicon substrates via atmospheric-pressure plasma polymerization is reported. The process allows the synthesis of hydrogels with high conversion degree, which preserve the functionalities of both monomers as proven by XPS and FT IR analysis. Atomic force microscopy was conducted to characterize the wrinkle dimension, which revealed an increase of the wrinkle wavelength lambda and amplitude A with the film's thickness. The chemical and morphological properties of the hydrogel films are preserved, even after immersion in deionized water for several days, indicating the high stability of the plasma-polymerized hydrogels. The simplicity of atmospheric-pressure plasma polymerization to deposit responsive hydrogels which are highly stable and having tunable properties as materials on demand, will certainly extend the applications of plasma-based hydrogels especially for biomedical applications.

Automated summary

This study reports the fabrication of pH-responsive hydrogel coatings with microstructured wrinkles from a monomer mixture through atmospheric-pressure plasma polymerization. The hydrogels showed high conversion degree and preserved the functionalities of both monomers. Atomic force microscopy was used to characterize the wrinkle dimension, which increased with the film's thickness. The hydrogel films maintained their chemical and morphological properties even after immersion in deionized water for several days, demonstrating high stability. The simplicity of atmospheric-pressure plasma polymerization enables the deposition of highly stable and tunable hydrogels, which will extend their applications in biomedical fields.