Influence of the Casting Solvent on the Thermotropic Alignment of Thin Liquid Crystalline Polyfluorene Copolymer Films
Influence of the Casting Solvent on the Thermotropic Alignment of Thin Liquid Crystalline Polyfluorene Copolymer Films
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DOI:
10.1021/ma035775h
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发表时间:
2004-07
期刊:
影响因子:
5.5
通讯作者:
M. Banach;R. Friend;H. Sirringhaus
中科院分区:
文献类型:
--
作者:
M. Banach;R. Friend;H. Sirringhaus
The morphology of a conjugated polymer thin film determines how it will behave as an active layer in optoelectronic devices. The liquid crystalline phase present in some conjugated polymers offers a unique way of controlling the film morphology. For example, films in which the chains are aligned in a single direction can be fabricated by processing films on a templating layer and annealing them above the liquid crystalline melting point of the polymer. However, the ability to align to a templating layer will be influenced by the character of the as-cast film. This effect was examined by casting poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) films from a range of both aromatic and chlorinated solvents on top of rubbed polyimide layers and aligning via the thermotropic melt. Measurements of the dichroic ratio as a function of annealing time revealed that films cast from high boiling point aromatic solvents like isodurene (ISO) and o-xylene (OXY) aligned well with a maximum dichroic ratio over 10. Film...