Solvent Dependent Assembly of a Polyfluorene−Polythiophene 'Rod−Rod' Block Copolyelectrolyte: Influence on Photophysical Properties
| Autor: | Matti Knaapila, Michael Forster, Hugh D. Burrows, Mika Torkkeli, Rachel C. Evans, Ullrich Scherf, Andrea Gutacker, V. M. Garamus, Sylwia Adamczyk |
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| Rok vydání: | 2010 |
| Předmět: |
Photoluminescence
Quantum yield 02 engineering and technology Surfaces and Interfaces Fluorene 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences 0104 chemical sciences Solvent Polyfluorene chemistry.chemical_compound Crystallography chemistry Electrochemistry Thiophene Polythiophene Organic chemistry General Materials Science 0210 nano-technology Spectroscopy Tetrahydrofuran |
| Zdroj: | Langmuir. 26:5056-5066 |
| ISSN: | 1520-5827 0743-7463 |
| DOI: | 10.1021/la903520w |
| Popis: | We report the solvent-driven assembly of a polyelectrolytic polyfluorene-polythiophene diblock copolymer-poly[9,9-bis(2-ethylhexyl)fluorene]-b-poly[3-(6-trimethylammoniumhexyl)thiophene] (PF2/6-b-P3TMAHT)-in tetrahydrofuran (THF), water, their 1:1 mixture and in subsequently prepared thin films, as investigated using a combination of scattering, microscopic and photoluminescence techniques. In solution PF2/6-b-P3TMAHT forms large (100 nm) aggregates which undergo a transition from objects with surface fractal interface (THF) to ones with a significant planar component due to the presence of the 2-dimensionally merged ribbon-like aggregates or fused walls of the observed vesicular aggregates [THF-water (1:1)]. In THF-water and water the blocks are loosely segregated into P3TMAHT and PF2/6 rich domains, with PF2/6 dominating the aggregate interior. Depending on solvent, the spun films contain either aggregates with a crystalline interior (THF) or large 200 nm-2 microm vesicular aggregates embedded in a featureless matrix (THF-water and water). Structural variations are concomitant with distinctive solvatochromic changes in the photophysical properties including a color change from deep red (THF) to pale orange (THF-water and water) in solution, a decrease in fluorescence quantum yield with increasing water content, and a shift from photoluminescence of individual PF2/6 blocks (THF) to efficient PF2/6 --P3TMAHT energy transfer (THF-water and water). |
| Databáze: | OpenAIRE |
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