Stability and Catalytic Activity of PEG-b-PS-Capped Gold Nanoparticles: A Matter of PS Chain Length
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- 作者：Yurong Que ; Chun Feng ; Sen Zhang ; Xiaoyu Huang
- 刊名：Journal of Physical Chemistry C
- 出版年：2015
- 出版时间：January 29, 2015
- 年：2015
- 卷：119
- 期：4
- 页码：1960-1970
- 全文大小：503K
- ISSN：1932-7455
文摘
Gold nanoparticles (AuNPs) covered with a series of well-defined poly(ethylene glycol)-b-polystyrene (PEG-b-PS) amphiphilic diblock copolymers containing a thiol group at the end of PS block were prepared to explore the influence of chain length of PS segment on the colloidal stability and catalytic activity of AuNPs. PEG-b-PS amphiphilic diblock copolymers with different PS chain lengths and narrow molecular distributions (Mw/Mn 鈮?1.15) were synthesized by reversible addition鈥揻ragmentation chain transfer (RAFT) polymerization employing a PEG-based macromolecular chain transfer agent (Mn 鈮?2000 g/mol), followed by transforming the thiocarbonate end functionality into a thiol group in the presence of 2-aminoethanol and tributylphosphane. PEG-b-PS-stabilized gold nanoparticles (Au@PEG-b-PS) were prepared by ligand exchange reaction between citrate-stabilized AuNPs and the thiol end group of PEG-b-PS diblock copolymer. The presence of the hydrophobic PS layer not only improved the stability of Au@PEG-b-PS against electrolyte-induced aggregation but also greatly promoted the resistance of Au@PEG-b-PS against competitive displacement of dithiothreitol. Au@PEG-b-PS showed excellent catalytic activity in the reduction reaction of 4-nitrophenol into 4-aminophenol, and the catalytic activity increased with the decrease in the chain length of PS block. In addition, the high stability imparted by the PS layer endowed Au@PEG-b-PS with good reusability in catalysis without the loss of catalytic activity.