Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan.
Colloids Surf B Biointerfaces. 2012 Dec 1;100:126-32. doi: 10.1016/j.colsurfb.2012.05.008. Epub 2012 May 17.
A zwitterionic poly(carboxymethylbetaine) (PCMB) brush was prepared on a fused quartz prism by the surface-initiated atom transfer radical polymerization (SI-ATRP) of CMB monomer. The conformation of PCMB brush and the state of water at the surface of the brush were examined using sum frequency generation (SFG) technique. The C-H stretching band of the brush, indicating the gauche defect of the brush, was affected by the contact medium such as dry nitrogen, water vapor-saturated nitrogen and liquid water. The water molecules at the PCMB-water interfaces were not largely oriented in comparison with the interfacial water of both bare and the ATRP-initiator-modified quartz prisms. The similar tendency was previously observed for water in the vicinity of water-soluble zwitterionic polymers and polymer thin films using Raman and attenuated total reflection (ATR) infrared spectroscopies, respectively. The electrical neutralization between neighboring positive and negative charges might diminish the electrostatic adsorption of water molecules to the vicinity of zwitterionic polymer brushes.
聚（羧甲基甜菜碱）（PCMB）两性离子刷通过 CMB 单体的表面引发原子转移自由基聚合（SI-ATRP）在熔融石英棱镜上制备。使用和频发生（SFG）技术研究了 PCMB 刷的构象和刷表面水的状态。刷的 C-H 伸缩带，表明刷的 gauche 缺陷，受到诸如干燥氮气、水蒸气饱和氮气和液态水等接触介质的影响。与裸和 ATRP-引发剂修饰的石英棱镜的界面水相比，PCMB-水界面处的水分子没有大的取向。使用拉曼和衰减全反射（ATR）红外光谱法，分别在附近的水溶性两性离子聚合物和聚合物薄膜中的水观察到类似的趋势。相邻正负电荷之间的电中和可能会减少水分子对两性离子聚合物刷附近的静电吸附。
