Quenching effects of gold nanoparticles in nanocomposites formed in watersoluble conjugated polymer nanoreactors

Po Jen Yang, Hsuan Chih Chu, Yu Hsien Lee, Takayoshi Kobayashi, Te Cheng Chen, Hong-Cheu Lin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

In this paper we describe the first example of the in situ synthesis of gold nanoparticles (AuNPs) in the presence of a water-soluble conjugated polyfluorene (NPF) presenting pendent ammonium groups, with the polymer acting as an aqueous surfactant and providing fluorescent nanoreactors. Using this approach, we produced well-dispersed NPF-AuNP nanocomposites without the need for any additional reducing agents. The photoluminescence emission intensity of NPF-AuNP nanocomposite solution was quenched to a greater extent upon increasing the concentration of AuNPs, presumably through energy transfer or electron transfer from the fluorescent polymer to the metal nanoparticles. Through variations in the degrees of protonation and deprotonation of the amino groups of NPF at different values of pH, we found that the extent of quenching of AuNPs in NPF-AuNP nanocomposite solutions was directly related to the adsorption and desorption behavior of NPF on the metal surfaces. Transmission electron microscopy revealed that the greatest aggregation of AuNPs in the nanocomposite solution occurred at pH 3, suggesting that the ammonium groups (RNMe2 at pH 8.5; RNMe2H at pH 3) of the polymer side chains adsorbed onto the AuNP surfaces under these conditions. Distinct time-resolved fluorescence signals of the AuNP-quenched NPF polymers at different values of pH confirmed the interactions between these species.

Original languageEnglish
Pages (from-to)939-946
Number of pages8
JournalPolymer
Volume53
Issue number4
DOIs
StatePublished - 17 Feb 2012

Keywords

  • Aqueous surfactant
  • Gold nanoparticle
  • Water-soluble conjugated polyfluorene

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