Synthesis, nanostructure, functionality and application of polyfluorene-block-poly(N-isopropylacrylamide)s

Yanqing Tian, Ching Yi Chen, Hin Lap Yip, Wen-Chung Wu, Wen Chang Chen, Alex K.Y. Jen

研究成果: Article同行評審

48 引文 斯高帕斯(Scopus)

摘要

A series of amphiphilic rod-coil diblock copolymers with a polyfluorene (PF) as a hydrophobic and light-emitting rod and a poly(Ar-isopropylacrylamide) (PNIPAAm) as a hydrophilic coil were prepared. Their micellar nanostructures and fluorescence properties were stimulated using solvents, e.g., water and tetrahydrofuran (THF)/toluene (1:10 by volume), which were characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), atomic force microscopy (AFM), and fluorescence spectroscopy. A typical block copolymer P2 (Mn = 14 400, Mw/Mn = 1.80, the PF weight fraction is 9.4%) in water exhibited micelles with the PNIPAAm block as the corona, whereas the polymer showed inverse micelles in mixed organic solvents of THF/toluene with PF as the corona. Such different nanostructures resulted in their different fluorescence properties. The fluorescence spectrum of P2 did not indicate aggregations of the PF chains in the THF/toluene mixture. Blue emission with a high quantum yield (0.80) was observed. In contrast, strong aggregations of the PF chains were observed in the aqueous solution, resulting in low quantum efficient (0.26) fluorescence. These results clearly demonstrated that the functionality of the P2 could be tuned through the solvent stimuli. The micelles of P2 were further used as nanocarriers to load a water-insoluble tetrakis(mesityl)porphyrin (H2(Me3)TPP) into its micellar aqueous solution. Efficient fluorescence resonance energy transfer (FRET) between the PF (donor) and H2(Me3)TPP (acceptor) (as high as 98 % quenching of donor emission) was observed in their micellar solutions. Moreover, FRET contributes significantly to the efficiency of singlet oxygen generation from H2(Me3)TPP molecules (with an efficiency factor of 2 as compared to non-FRET micelles). This study provided a feasible way to enable the application of water-insoluble porphyrin in aqueous solution and enhance its singlet oxygen generation efficiency.

原文English
頁(從 - 到)282-291
頁數10
期刊Macromolecules
43
發行號1
DOIs
出版狀態Published - 2010 一月 12

All Science Journal Classification (ASJC) codes

  • 有機化學
  • 聚合物和塑料
  • 無機化學
  • 材料化學

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