Grishina V S, Vikhrenko V S, Ciach A
Belarusian State Technological University, 13a Sverdlova str., 220006 Minsk, Belarus.
Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa, Poland.
J Phys Condens Matter. 2020 Jul 1;32(40). doi: 10.1088/1361-648X/ab9979.
Triangular lattice models for pattern formation by hard-core soft-shell particles at interfaces are introduced and studied in order to determine the effect of the shell thickness and structure. In model I, we consider particles with hard-cores covered by shells of cross-linked polymeric chains. In model II, such inner shell is covered by a much softer outer shell. In both models, the hard cores can occupy sites of the triangular lattice, and nearest-neighbor repulsion following from overlapping shells is assumed. The capillary force is represented by the second or the fifth neighbor attraction in model I or II, respectively. Ground states with fixed chemical potentialor with fixed fraction of occupied sitesare thoroughly studied. For> 0, the() isotherms, compressibility and specific heat are calculated by Monte Carlo simulations. In model II, 6 ordered periodic patterns occur in addition to 4 phases found in model I. These additional phases, however, are stable only at the phase coexistence lines at the (,) diagram, which otherwise looks like the diagram of model I. In the canonical ensemble, these 6 phases and interfaces between them appear in model II for large intervals ofand the number of possible patterns is much larger than in model I. We calculated line tensions for different interfaces, and found that the favorable orientation of the interface corresponds to its smoothest shape in both models.
为了确定壳层厚度和结构的影响，引入并研究了用于描述界面处硬核软壳粒子图案形成的三角晶格模型。在模型I中，我们考虑具有硬核的粒子，其被交联聚合物链壳层覆盖。在模型II中，这样的内壳层被更软的外壳层覆盖。在这两个模型中，硬核可以占据三角晶格的格点，并假设壳层重叠会产生最近邻排斥。在模型I和模型II中，毛细力分别由第二近邻或第五近邻吸引力表示。对具有固定化学势或固定占据格点分数的基态进行了深入研究。对于> 0，通过蒙特卡罗模拟计算了()等温线、压缩率和比热。在模型II中，除了在模型I中发现的4个相之外，还出现了6种有序周期图案。然而，这些额外的相仅在(,)图中的相共存线上是稳定的，否则该图看起来与模型I的图相似。在正则系综中，对于较大的区间，模型II中会出现这6个相以及它们之间的界面，并且可能的图案数量比模型I中的大得多。我们计算了不同界面的线张力，发现在两个模型中，界面的有利取向对应于其最平滑的形状。
