Control of Microstructure and Gradient Property of Polymer Network by Photopolymerizable Silicone-Containing Nanogel

This article reports a new type of siliconecontaining nanogel. The nanogel was dispersed in triethylene glycol dimethacrylate (TEGDMA) in increments between 10 and 40 wt % with a series of properties evaluated before and after polymerization. The nanogel raised monomer viscosity but did not significantly affect reaction kinetics or final conversion attained during photopolymerization. Polymerization stress was reduced progressively with the addition of nanogel with a significant delay in the onset of stress observed compared with the control. The self-floating ability of the nanogel was demonstrated by elemental analysis and X-ray photoelectron spectroscopy. As a result, the nanogel spontaneously formed a concentration gradient in the monomer prior to photopolymerization, leading to a gradient change of properties of the polymer. The research on surface morphology and elemental composition of PTEGDMA indicated the enrichment of the nanogel on the polymer surface, which resulted in enhanced hydrophobic character along with altered surface microstructure. (C) 2014 Wiley Periodicals, Inc.