Chemical and Topographical Modification of Polycarbonate Surfaces through Diffusion/Photocuring Processes of Hydrogel Precursors Based on Vinylpyrrolidone

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.langmuir. 6b04143. Raman spectra of the PC used as a substrate for the hydrogel formation, a pure hydrogel constructed from VP, and the modified surface resulting upon photopolymerization and hydrogel detachment. Raman confocal spectra of a PC surface treated with a photopolymerizable monomer mixture. Hydrogel swelling as a function of the solvent used and the amount of crosslinking agent used. Optical image and 3D image of a pristine PC surface together with roughness measurement (PDF)Facile procedures capable of simultaneously conferring hydrophilicity and tailored topography to surfaces of hydrophobic supports, such as polycarbonate (PC), are very attractive but rare. In this work, we describe a simple methodology to wrinkle PC surfaces after a process of (a) contacting with a photopolymerizable vinylic solution, (b) UV curing of such solutions, and (c) detachment of the formed polymer network, upon swelling in ethanol. The influence of different parameters such as contact lag time between the PC surface and the polymerizable solution, the monomer concentration and type of solvents, as well as the cross-linking degree on the formation of wrinkles, has been studied. The dimensions of the wrinkles can be tailored to some extent by altering the different parameters. Surface chemistry has been analyzed by contact angle measurements and by confocal Raman microscopy. The results are consistent with a chemical alteration of the surface and the formation of an outer hydrogel layer, which is interpenetrated into the PC structure. A mechanism of monomer diffusion and PC swelling that produces surface instabilities and wrinkling is proposed.The authors gratefully acknowledge support from the Consejo Superior de Investigaciones Cientifí cas (CSIC). Equally, this work was financially supported by the Ministerio de Economía y Competitividad (MINECO) through MAT2013-47902-C2-1- R, MAT2013-42957-R, and MAT2016-78437-R.Peer Reviewe