Fabrication of pH-Responsive Nanocomposites of Gold Nanoparticles/Poly(4-vinylpyridine)

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• 作者：Dongxiang Li ; Qiang He ; Yue Cui ; Junbai Li
• 刊名：Chemistry of Materials
• 出版年：2007
• 出版时间：February 6, 2007
• 年：2007
• 卷：19
• 期：3
• 页码：412 - 417
• 全文大小：548K
• 年卷期：v.19,no.3(February 6, 2007)
• ISSN：1520-5002

文摘

Novel nanocomposites of gold nanoparticle and poly(4-vinylpyridine) (Au@PVP) were fabricatedthrough surface-initiated atom-transfer radical polymerization (SI-ATRP) at ambient conditions. The citrate-stabilized gold nanoparticles were first modified by a disulfide initiator for ATRP initiation, and thefollowing polymerization of 4-vinylpyridine (4VP) occurred on the surface of gold particles. The assembledAu@PVP nanocomposites are pH-responsive because of the pyridyl groups, which are facially protonatedand positively charged. At low pH (<3.2), the polymer chains attached on gold nanoparticles are expandedby electrostatic forces, and the polymer layer is loosely swelled; hence, the Au@PVP composite particledisplays a comatulid-like nanostructure in 3-D AFM images. However, at a relatively high pH (>3.2),the polymer chains shrink and wrap around the gold particle surface, which results in the aggregation ofgold nanoparticles with a thin shrunken polymer layer under TEM observation. Such assembled Au@PVPnanocomposites as a smart supporter can entrap transition metal ions by their efficient coordinatingsegments, and subsequently, the metal ions can be reduced in situ to construct novel bimetallicnanocomposites, which are regarded as intelligent catalysts with environmental stimuli activity.