Nanoparticle Enlarged Interfacial Effect on Phase Transition of 1-Octadecanol/Silica Composites

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• 作者：Xia Gao ; Baoquan Xie ; Yunlan Su ; Dongsheng Fu ; Dujin Wang
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：February 5, 2015
• 年：2015
• 卷：119
• 期：5
• 页码：2074-2080
• 全文大小：329K
• ISSN：1520-5207

文摘

Motivated by the interest in an interfacial effect on crystallization behaviors and material properties of polymer nanocomposites, phase behaviors of a novel model system for polymer nanocomposite, 1-octadecanol/silica nanosphere composites (C₁₈OH/SiO₂), were studied by means of thermal analysis and wide-angle X-ray diffraction. Although a huge specific surface area of silica nanoparticles enlarges the surface鈥搗olume ratio of C₁₈OH molecules, surface freezing phenomenon is not observed by DSC in the C₁₈OH/SiO₂ composites. While pure C₁₈OH exhibits rotator R_IV phase with molecules tilted with respect to the layer normal, the silica network favors and enhances untitled R_II phase by disturbing the layering arrangement. Moreover, the confined C₁₈OH shows a polycrystalline mixture of orthorhombic 尾 form and monoclinic 纬 form. It is demonstrated that the interfacial interaction between the C₁₈OH molecules and the silica surface contributes to the peculiar phase transition behaviors of C₁₈OH/SiO₂ composites. The investigation of the model system of long-chain alcohol/nano-SiO₂ composites may help us to understand the complicated interfacial effect on phase behaviors and material properties of polymer nanocomposite systems.