Kawaguchi Daisuke, Yamamoto Kentaro, Abe Tatsuki, Jiang Naisheng, Koga Tadanori, Yamamoto Satoru, Tanaka Keiji
Department of Applied Chemistry, Kyushu University, Fukuoka 819-0395, Japan.
Center for Polymer Interface and Molecular Adhesion Science, Kyushu University, Fukuoka 819-0395, Japan.
Phys Chem Chem Phys. 2021 Oct 27;23(41):23466-23472. doi: 10.1039/d1cp03959h.
A better understanding of the aggregation states of polymer chains in thin films is of pivotal importance for developing thin film polymer devices in addition to its inherent scientific interest. Here we report the preferential orientation of the crystalline lamellae for isotactic polypropylene (iPP) in spin-coated films by grazing incidence of wide-angle X-ray diffraction in conjunction with sum frequency generation vibrational spectroscopy, which provides information on the local conformation of chains at crystal/amorphous interfaces buried in a thin film. The crystalline orientation of iPP, which formed cross-hatched lamellae induced by lamellar branching, altered from a mixture of edge-on and face-on mother lamellae to preferential face-on mother lamellae with decreasing thickness. The orientation of methyl groups at the crystal/amorphous interfaces in the interior region of the iPP films changed, accompanied by a change in the lamellar orientation.
除了其内在的科学价值外，更好地理解聚合物链在薄膜中的聚集状态对于开发薄膜聚合物器件至关重要。在此，我们通过掠入射广角X射线衍射结合和频振动光谱，报道了旋涂膜中等规聚丙烯（iPP）结晶片晶的择优取向，和频振动光谱提供了关于埋在薄膜中的晶体/非晶界面处链的局部构象的信息。由片晶分支诱导形成交叉阴影片晶的iPP的晶体取向，随着厚度减小，从边缘取向和正面取向的母片晶混合物变为择优的正面取向母片晶。iPP薄膜内部区域晶体/非晶界面处甲基的取向发生变化，同时片晶取向也发生变化。
