Poly(N-isopropylacrylamide)/Gold Hybrid Hydrogels Prepared by Catechol Redox Chemistry. Characterization and Smart Tunable Catalytic Activity

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• 作者：Gema Marcelo ; Mar L贸pez-Gonz谩lez ; Francisco Mendicuti ; M. Pilar Tarazona ; Mercedes Valiente
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：September 9, 2014
• 年：2014
• 卷：47
• 期：17
• 页码：6028-6036
• 全文大小：473K
• ISSN：1520-5835

文摘

PNIPAM hydrogels functionalized with gold nanoparticles were prepared by making use of catechol redox chemistry. For this purpose catechol groups were introduced in the PNIPAM network during the cross-linking polymerization process (PNIPAM鈥揷atecholx hydrogel). These groups act as reducing agents of HAuCl_4, which enables the functionalization of the PNIPAM with gold nanoparticles (PNIPAM鈥揷atecholx@Au hydrogel). The rheological study shows that catechol groups reinforce the hydrogel structure. A stronger effect was observed after the functionalization of the hydrogel with gold nanoparticles. This influence could be easily observed since the variation of G鈥?with the MBA mole fraction was fitted to a power-law expression G鈥?鈭?x_MBA^a, with a = 1.6 for PNIPAMx hydrogels, a = 2.3 for PNIMPAM鈥揷atecholx hydrogels and a = 3.2 for PNIMPAM鈥揷atecholx@Au hydrogels. The capability of the PNIPAM鈥揷atecholx@Au hydrogel to act as a tunable catalyst was demonstrated with a model reduction reaction. The half-lifetime at 25 掳C was 10.5 min; however, at 38 掳C the half-lifetime was 133 min.