水的流动性仅限于亚纳米薄膜
Nature
|September 7, 2001
概括
纳米级膜中的水的粘度保持在接近散装水平,与有机溶剂不同. 限制影响水通过破坏键,而不是分子翻译,保持流动性.
科学领域:
- 物理化学 物理化学
- 材料科学 材料科学 材料科学
- 纳米技术纳米技术
背景情况:
- 水在狭窄的几何结构中的分子流动性对各种科学领域至关重要,包括三角学和蛋白质折叠.
- 以前的研究表明,膜中的水粘度>2-3纳米与散装相似,反映了非关联性有机液体.
研究的目的:
- 为了研究水的有效粘度,局限于纳米尺寸的薄膜.
- 为了比较水的行为与有机溶剂在类似的限制条件下.
主要方法:
- 在封闭膜中直接测量液体流量.
- 分析纳米孔和裂内的分子流动性.
主要成果:
- 水的有效粘度保持在其散价值的三倍之内,即使在薄薄的0.4纳米薄膜中也是如此.
- 这与有机溶剂形成鲜明对比,其粘度在限制在<5-8个分子层时显著增加 (分离).
结论:
- 水在封闭状态下的独特行为归因于不同的固化机制.
- 封闭主要是破坏水的结网络,而不是抑制转化自由,从而保持流动性.
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