Chinese Journal of Applied Chemistry

• Full Papers • Previous Articles     Next Articles

Preparation of polymer methacrylate monolayer-protected GNPs and its pH responsive catalyst

LI Junbo1*, LI  Guizhen1, LIU Zhifei2, HAN Chen1, ZHOU Huiyun1, ZHANG Junkai1   

  1. (1.College of Chemical Engineering & Pharmaceutics,Henan University of Science & Technology,Luoyang 471003,China;
    2.Quality and Technical Supervision Inspection Center of Luoyang City,Luoyang 471000,China)
  • Received:2012-01-04 Revised:2012-02-26 Online:2012-10-10 Published:2012-10-10

Abstract: The pH stimuli-sensitive polymer, poly(methylacrylic acid)(PMAA), was firstly obtained by reversible addition-fragmentation transfer(RAFT) polymerization of tert-butylmethacrylate(PtBMA) and then hydrolysis. The PMAA monolayer-protected gold nanoparticles(PMAA-GNPs) was prepared via the strong binding between the thiol groups on the polymer chain-ends and gold. The dispersion and aggregation of PMAA-GNPs could be tuned by controlling the pH values of the solution, which was investigated by UV-Vis spectra and TEM. It was found that the catalytic activity was responsive to pH when it is applied in the catalytic reduction of the 4-nitrophenol by NaBH4. The responsive mechanism could be interpreted as: the hydrophobic PMAA collapsed onto the surface of the GNPs in the acid solution, which hindered the contaction between reactant and GNPs, and reduced the catalytic activity. On the contrary, in the alkaline system, polymer chains repulsion due to electrostatic effect can improve the catalytic activity.

Key words: Poly(methylacrylic acid), gold nanoparticles, pH responsive, catalyst

CLC Number: