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

doi:10.1021/ma9019619

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

Research output: Contribution to journal › Article › peer-review

53 Scopus citations

Abstract

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 (M_n = 14 400, M_w/M_n = 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.

Original language	English (US)
Pages (from-to)	282-291
Number of pages	10
Journal	Macromolecules
Volume	43
Issue number	1
DOIs	https://doi.org/10.1021/ma9019619
State	Published - Jan 12 2010
Externally published	Yes

ASJC Scopus subject areas

Organic Chemistry
Polymers and Plastics
Inorganic Chemistry
Materials Chemistry

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10.1021/ma9019619

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

abstract = "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.",

author = "Yanqing Tian and Chen, {Ching Yi} and Yip, {Hin Lap} and Wu, {Wen Chung} and Chen, {Wen Chang} and Jen, {Alex K.Y.}",

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doi = "10.1021/ma9019619",

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T1 - Synthesis, nanostructure, functionality and application of polyfluorene-block-poly(N-isopropylacrylamide)s

AU - Tian, Yanqing

AU - Chen, Ching Yi

AU - Yip, Hin Lap

AU - Wu, Wen Chung

AU - Chen, Wen Chang

AU - Jen, Alex K.Y.

PY - 2010/1/12

Y1 - 2010/1/12

N2 - 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.

AB - 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.

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

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