Structure of water at zwitterionic copolymer film-liquid water interfaces as examined by the sum frequency generation method
Structure of water at zwitterionic copolymer film-liquid water interfaces as examined by the sum frequency generation method
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DOI：
10.1016/j.colsurfb.2013.08.051
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发表时间：
2014-01-01
影响因子：
5.8
通讯作者：
Saruwatari, Yoshiyuki
中科院分区：
文献类型：
--
作者：
Kondo, Takuya;Nomura, Kouji;Saruwatari, Yoshiyuki
将两性离子型羧甲基甜菜碱（CMB）和甲基丙烯酸正丁酯（BMA）的共聚物（Poly（CMB-r-BMA））浇铸在半圆柱形的十八烷基三氯硅烷（ODS）改性的熔融石英棱镜的平面上。利用和频产生技术研究了聚合物膜的C-H伸缩和膜表面水的O-H伸缩。C-H伸缩带表明薄膜存在一个“笨拙”缺陷，它受接触介质的影响，接触介质包括干燥氮气、水蒸气饱和氮气和液态水。相比之下，引入到石英棱镜上以稳定附着流延膜的十八烷基的C-H伸缩未被接触介质显著改变。O-H伸缩带表明，与裸棱镜、ODS SAM改性棱镜、覆盖有PolyBMA膜或BMA与甲基丙烯酸或甲基丙烯酸2-（二甲氨基）乙酯的共聚物膜的棱镜相比，在与液态水接触的Poly（CMB-r-BMA）膜的表面处的水分子没有很大的取向。水的结构的类似的小扰动先前分别使用拉曼和衰减全反射红外光谱在水溶性两性离子聚合物和两性离子共聚物膜附近观察到。提出了电荷中和对聚合物材料周围界面水结构扰动的明显影响。(C)2013爱思唯尔有限公司版权所有。
A copolymer film composed of zwitterionic carboxymethylbetaine (CMB) and n-butyl methacrylate (BMA), Poly(CMB-r-BMA), was cast on a flat plane of an octadecyltrichlorosilane (ODS)-modified fused quartz prism with a semi-cylindrical shape. C-H stretching of the polymer film and O-H stretching of water at the surface of the film were examined using the sum frequency generation (SFG) technique. The C-H stretching band of the cast film, indicating a gauche defect of the film, was affected by the contact medium including dry nitrogen, water vapor-saturated nitrogen and liquid water. In contrast, the C-H stretching of an octadecyl group introduced onto the quartz prism for stable attachment of the cast film was not significantly changed by the contact medium. The O-H stretching band indicated that water molecules at the surface of the Poly(CMB-r-BMA) film in contact with liquid water were not greatly oriented in comparison with those at the surfaces of a bare prism, an ODS SAM-modified prism, and a prism covered with a PolyBMA film or a copolymer film of BMA and methacrylic acid or 2-(dimethylamino)ethyl methacrylate. A similar small perturbation of the structure of water was previously observed in the vicinity of water-soluble zwitterionic polymers and zwitterionic copolymer films using Raman and attenuated total reflection infrared spectroscopies, respectively. A distinct effect of charge neutralization to diminish the perturbation of the structure of interfacial water around polymer materials was suggested. (C) 2013 Elsevier B.V. All rights reserved.