Relationship between the Microstructure Development and the Photoluminescence Efficiency of Electrospun Poly(9,9-dioctylfluorene-2,7-diyl) Fibers

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• 作者：Chia-Cheng Lee ; Shin-Yi Lai ; Wen-Bin Su ; Hsin-Lung Chen ; Cho-Liang Chung ; Jean-Hong Chen
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：October 10, 2013
• 年：2013
• 卷：117
• 期：40
• 页码：20387-20396
• 全文大小：620K
• 年卷期：v.117,no.40(October 10, 2013)
• ISSN：1932-7455

文摘

In this work, we established the relationship between the thermally induced microstructure development and the photoluminescence efficiency (E_p) of the poly(9,9-dioctylfluorene) (PF8) fibers prepared from the semidilute PF8/chloroform solutions by direct electrospinning. The as-spun (AS) fibers were found to be composed of an amorphous phase and a significant fraction of mesomorphic 尾-phase, which may promote the E_p of PF8. The temperature-dependent wide-angle X-ray scattering (WAXS) measurement revealed that the PF8 fibers exhibited complex structural transformation on heating from the AS state, and there existed a strong correlation between E_p and the microstructure developed. The AS fibers exhibited the highest E_p value. The E_p decreased progressively on heating at temperatures below the cold crystallization temperature (T_cc), where the microstructure remained unperturbed. The 尾-phase transformed to 纬- or 伪鈥?phase (C_纬-/C_{伪鈥?/sub>-crystals) above Tcc, and such a structural transformation led to a reduction of Ep. With further heating, the C纬-/C伪鈥?/sub>-crystals transformed into the more stable C伪-crystals, presumably as the premelting鈥搑eorganization鈥搑emelting proceeded at the temperatures over the crystal transformation temperature (Tct). The crystal transformation process reduced the Ep markedly. Finally, above the melting temperature (Tm), the C伪-crystals were disrupted into the disordered molten state, and the Ep value remained largely unchanged up to 200 掳C.}