We study the influence of mobility of the confining media in the structural and dynamical properties of a core-softened fluid under confinement. The fluid is modeled using a two-length scale potential, which reproduces in bulk the anomalous behavior observed in water. We perform simulations in the $NVT$ ensemble with fixed flat walls and in the $NpT$ ensemble using a fluctuating wall control of pressure to study how the fluid behavior is affected by fixed and non-fixed walls. Our results indicate that the fluid dynamical and structural properties are strongly affected by the wall mobility. The distinct observed behavior are explained in the framework of the two length scale potential.
Effects of rigid or adaptive confinement on colloidal self-assembly. Fixed vs. fluctuating number of confined particles
在[J. Pakkalski et al. J. Chem. Phys. 142,014903(2015)]中的大正则方程组(GCE)中精确求解的一维晶格模型中,研究了在固定数量的受限粒子的情况下,受限对胶体自组装的影响。该模型考虑了由短程吸引加上长程排斥定义的对相互作用。我们考虑与自组装成团簇相对应的热力学状态。固定和自适应边界进行了研究。对于固定的边界,有一些特殊的状态,在这些状态中,对于相等的平均密度,GCE中的团簇数量大于正则包围圈中的团簇数量。当系统尺寸随颗粒数的变化而变化时,压力对密度的依赖关系与当颗粒数随系统尺寸的变化而变化时有不同的形式。在前一种情况下,压力对系统尺寸有非单调的依赖关系。膨胀系统压力的异常增加伴随着大量小团簇的形成。在弹性约束面的情况下,我们观察到一个双稳态,即两个显着不同的系统大小发生几乎相同的概率。在封闭系统中的双稳态的机制是不同的情况下的渗透壁,其中两个平衡系统的大小对应于不同数量的颗粒。
Aalto University School of Science and Technology(阿尔托大学理工学院);The University of Western Ontario(韦仕敦大学);University of Waterloo(滑铁卢大学);Brown University(布朗大学)