Molecular Orientations and Conformations of Air/Fluoroalkyl Acrylate Polymer Interfaces Studied by Heterodyne-Detected Vibrational Sum Frequency Generation
Molecular Orientations and Conformations of Air/Fluoroalkyl Acrylate Polymer Interfaces Studied by Heterodyne-Detected Vibrational Sum Frequency Generation
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DOI：
10.1021/acs.macromol.9b00541
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发表时间：
2019-11
期刊：
影响因子：
5.5
通讯作者：
Masanari Okuno;Osamu Homma;A. Kuo;S. Urata;Ryohei Koguchi;T. Miyajima;T. Ishibashi
中科院分区：
文献类型：
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作者：
Masanari Okuno;Osamu Homma;A. Kuo;S. Urata;Ryohei Koguchi;T. Miyajima;T. Ishibashi
利用外差检测振动和频率产生（HD-VSFG）光谱研究了空气/氟烷基丙烯酸酯聚合物界面。作为氟烷基丙烯酸酯聚合物，研究了侧链上带有C6F13基团的聚（2-全氟己基丙烯酸酯）（p-C6FA）和带有C8F17基团的聚（2-全氟辛基丙烯酸酯）（p-C8FA）。虽然这两种聚合物仅在侧链中氟烷基的长度不同，但它们的空气/聚合物界面给出了完全不同的VSFG光谱。在1300 ~ 1550 cm-1的光谱范围内，空气/p-C8FA界面的VSFG谱以1370 cm-1的振动带为主，而空气/p-C6FA界面的VSFG谱则没有明显的振动带。参考空气/氟表面活性剂界面的极化HD-VSFG光谱，结合表面活性剂的拉曼测量和量子化学计算，1370 cm-1的VSFG波段归属于氟烷基末端的C-C拉伸与末端的C-C拉伸耦合。
Air/fluoroalkyl acrylate polymer interfaces have been investigated by heterodyne-detected vibrational sum frequency generation (HD-VSFG) spectroscopy. As fluoroalkyl acrylate polymers, poly(2-perfluorohexylethlyl acrylate) (p-C6FA) with the C6F13 group in its side chain and poly(2-perfluorooctylethlyl acrylate) (p-C8FA) with the C8F17 group were examined. Although the two polymers differ only in the length of the fluoroalkyl group in their side chains, air/polymer interfaces of them gave quite different VSFG spectra. In the spectral range from 1300 to 1550 cm–1, the VSFG spectrum of the air/p-C8FA interface was dominated by a vibrational band at 1370 cm–1, whereas that of the air/p-C6FA did not show any discernible vibrational band. By reference to polarized HD-VSFG spectra of an air/fluorosurfactant interface combined with Raman measurements and quantum chemical calculations of the surfactant, the 1370 cm–1 VSFG band was ascribed to the terminal C–C stretch of the fluoroalkyl group coupled with the termi...