Structural and mechanical properties of glassy water in nanoscale confinement.
Structural and mechanical properties of glassy water in nanoscale confinement.
复制标题
纳米级限制下玻璃水的结构和机械特性。
作者：
Thomas G. Lombardo;N. Giovambattista;P. Debenedetti
我们调查的结构和力学性能的玻璃水之间的硅基表面连续可调的疏水性和亲水性，通过计算和分析最低能量，机械稳定的配置（固有结构）。结构化的二氧化硅衬底在高密度（p >或= 1.0 g cm（-3））下在疏水限制下对第一层水分子施加长程有序。该近端层也以非常低的密度（p约0.4 g cm（-3））在亲水限制中结构化。疏水表面附近的水的有序化大大提高了薄膜的机械强度（0.8 nm）。这导致显著的应力各向异性;膜的横向强度超过正常强度500 MPa。大的横向强度导致能量景观的状态方程中的最小值，该最小值不对应于机械不稳定性，但表示壁旁边的有序水层的破坏。此外，我们发现，机械故障的模式是依赖于约束的类型。在大的横向应变下，亲水性表面限制的水优先在膜的中间形成空隙并且内聚失效。相反，在疏水限制下的水倾向于在壁附近形成空隙，并且由于失去粘附力而失效。
We investigate the structure and mechanical properties of glassy water confined between silica-based surfaces with continuously tunable hydrophobicity and hydrophilicity by computing and analyzing minimum energy, mechanically stable configurations (inherent structures). The structured silica substrate imposes long-range order on the first layer of water molecules under hydrophobic confinement at high density (p > or = 1.0 g cm(-3)). This proximal layer is also structured in hydrophilic confinement at very low density (p approximately 0.4 g cm(-3)). The ordering of water next to the hydrophobic surface greatly enhances the mechanical strength of thin films (0.8 nm). This leads to a substantial stress anisotropy; the transverse strength of the film exceeds the normal strength by 500 MPa. The large transverse strength results in a minimum in the equation of state of the energy landscape that does not correspond to a mechanical instability, but represents disruption of the ordered layer of water next to the wall. In addition, we find that the mode of mechanical failure is dependent on the type of confinement. Under large lateral strain, water confined by hydrophilic surfaces preferentially forms voids in the middle of the film and fails cohesively. In contrast, water under hydrophobic confinement tends to form voids near the walls and fails by loss of adhesion.
影响因子：
3.3
作者：
Hua, Lan;Huang, Xuhui;Berne, Bruce J.
通讯作者：
Berne, Bruce J.
影响因子：
15
作者：
Pometun,MaximS;Peterson,RonaldW;Babu,CharlesR;Wand,AJoshua
通讯作者：
Wand,AJoshua