通过线性和非线性光学光谱学研究的CTAB在水友性二氧化上的吸附
Eric Tyrode1, Mark W Rutland, Colin D Bain
1Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, United Kingdom.
Journal of the American Chemical Society
|December 5, 2008
概括
振动光谱检测显示,六甲基三甲化物 (CTAB) 吸附在二氧化上. 结果排除了不对称的聚合物,表明中心对称结构早期形成,影响水分子的方向.
科学领域:
- 表面科学是一门科学.
- 物理化学 物理化学
- 频谱学是一种光谱学.
背景情况:
- 像六甲基三甲基化 (CTAB) 这样的表面活性剂在表面的吸附对于理解界面现象至关重要.
- 描述吸附表面活性剂的结构和聚合状态对于控制表面性质至关重要.
研究的目的:
- 通过振动总频谱学 (SFS) 和总内部反射拉曼散射 (TIR Raman) 来研究CTAB在水友性二氧化上的吸附.
- 为了确定吸附的量,分子倾斜,聚合物结构和水分子在接口上的方向.
- 阐明CTAB吸附的结构模型,特别是在临界细胞度以下.
主要方法:
- 使用互补的振动总频谱学 (SFS) 和总内部反射拉曼散射 (TIR Raman).
- 分析不同CTAB度的光谱变化,以探测碳化合物链形状和头组相互作用.
- 量化水带变化,以了解水界结构和方向.
主要成果:
- TIR拉曼光谱显示CTAB度随着单调增加,表明碳化合物链的结构顺序没有显著变化.
- 在SF光谱中没有观察到来自CTAB头组或疏水链的可检测的峰值.
- 在SF光谱的水波段中显著的变化表明,由于表面电荷逆转,水分子的方向发生了变化.
- 模拟表明吸附的CTAB层中的不对称性不到单层的5%.
结论:
- 排除了半细胞,单层和其他不对称的聚合物的形成.
- 中心对称聚合物从吸附过程的早期阶段形成.
- 结果为CTAB在二氧化上吸附的结构模型提供了约束,特别是低于临界基度的结构模型.
相关概念视频
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