Abstract: Poly(ionic liquid) hydrogel was synthesized by radical polymerization of N-vinly-N′-ethylimidazolebromize and divinylbenzene, and then the hydrogel loading gold nanoparticles(GNPs) was obtained by one step in situ reduction. The dispersion of the gold nanoparticles in the poly(ionic liquid) hydrogel was studied, and the anion responsive aggregation was investigated by UV-Vis spectrum and TEM. It was found that the GNPs was well dispersed in the net of poly(ionic liquid) hydrogel with a spherical form(2~5 nm) and surface plasmon resonance(SPR) absorption peak at 527 nm due to the steric hindrance and electrostatic interactions. The hydrophobic hydrogel was formed due to the effect of PF-6, causing the contraction of the gel and the aggregation of the GNPs inside the gel. Consequently, the SPR absorption peak was shifted to 532 nm. The results indicate that this hydrogel has an anion responsiveness.

Key words: gold nanoparticles, Polymer ionic liquid, hydrogel, anion responsiveness