Higher-order structure formation of a poly(3-hydroxybutyrate) film during solvent evaporation
Higher-order structure formation of a poly(3-hydroxybutyrate) film during solvent evaporation
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DOI：
10.1039/c6ra20410d
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发表时间：
2016-10
期刊：
影响因子：
3.9
通讯作者：
Mengfan Wang;Khasanah;Harumi Sato;I. Takahashi;Jianming Zhang;Y. Ozaki
中科院分区：
文献类型：
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作者：
Mengfan Wang;Khasanah;Harumi Sato;I. Takahashi;Jianming Zhang;Y. Ozaki
采用时间分辨衰减全反射傅里叶变换红外光谱（ATR-FTIR）和掠入射广角X射线衍射（GI-WAXD）研究了聚3-羟基丁酸酯（PHB）在氯仿溶液中的溶剂蒸发结晶行为。ATR-FTIR研究表明，PHB/氯仿溶液最初为均相状态，随着氯仿的挥发，从氯仿溶剂中分离出来的PHB为中间态和无定形的混合物，但由于氯仿的存在，没有形成晶体结构。随后，进一步蒸发诱导从中间体到晶体结构的过渡，并在后者内形成CO → H-C分子内相互作用。随着晶体结构的发展，由于片层结构内分子内距离的减小，分子内相互作用由弱变强。GI-WAXD研究结果表明存在两种不同有序度（较低有序度和高度有序度）的中间结构。在SEC期间，首先形成中间结构，随后转化为晶体结构。
Solvent evaporation crystallization (SEC) of poly(3-hydroxybutyrate) (PHB) in a PHB/chloroform solution was investigated by time-resolved attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy and grazing incidence wide angle X-ray diffraction (GI-WAXD). The ATR-FTIR investigation reveals that the PHB/chloroform solution was in a homogeneous state at first, and with the evaporation of chloroform, the separated PHB from the chloroform solvent was in the mixture of intermediate and amorphous states, but no crystal structure formed due to the presence of chloroform. Subsequently, further evaporation induced a transition from intermediate to crystal structure and the formation of CO⋯H–C intramolecular interactions within the latter. As the crystal structure developed, the intra-molecular interaction changed from weak to strong due to the reduced intra-molecular distance within the lamella structure. The results of the GI-WAXD investigation suggest the presence of two kinds of intermediate structures with different order (less ordered and highly ordered). During SEC, the intermediate structures formed first, subsequently transforming into a crystal structure.