Gelation of a Solution of Poly(3-hexylthiophene) Greatly Retards Its Crystallization Rate in the Subsequently Cast Film

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• 作者：Kuei-Yu Kao ; Shen-Chuan Lo ; Hsin-Lung Chen ; Jean-Hong Chen ; Show-An Chen
• 刊名：Journal of Physical Chemistry B
• 出版年：2014
• 出版时间：December 11, 2014
• 年：2014
• 卷：118
• 期：49
• 页码：14510-14518
• 全文大小：621K
• ISSN：1520-5207

文摘

We compared the crystallization rate of poly(3-hexylthiophene) (P3HT) in the film cast from the gel (called 鈥済el-cast film鈥? with that in the film cast from the liquid solution (called 鈥渟olution-cast film鈥? to understand the effect of solution structure on the structural development in the subsequently cast film of conjugated polymer. P3HT was found to form a homogeneous liquid solution with xylene at elevated temperature. When the freshly prepared semidilute solution was allowed to age at room temperature, the solution transformed into a gel in which a significant amount of nanowhiskers formed. The nanowhiskers in the gel were effectively transferred to the corresponding cast film, while the film cast from the freshly prepared solution only contained a small amount of such a morphological entity. The in situ small-angle X-ray scattering (SAXS) measurement and thermal analysis revealed that both the cold and melt crystallization of P3HT in the gel-cast film were much slower than those in the solution-cast counterpart. The retardation of crystallization rate in the gel-cast film was attributed to the abundance of the nanowhiskers. In this case, the crystallization of P3HT occurred predominantly within the individual nanowhiskers and the mesh regions in the networks of the whiskers, where their limited sizes in at least one dimension imposed a strong spatial constraint to the crystal growth and chain motion for crystallization.