中国物理B ›› 2021, Vol. 30 ›› Issue (12): 124701-124701.doi: 10.1088/1674-1056/ac306c
Huaqing Liu(柳华清)1,†, Yiwu Zong(宗奕吾)1,†, Zhanglin Hou(侯章林)2, Thomas G. Mason3,4,‡, and Kun Zhao(赵坤)1,5,§
Huaqing Liu(柳华清)1,†, Yiwu Zong(宗奕吾)1,†, Zhanglin Hou(侯章林)2, Thomas G. Mason3,4,‡, and Kun Zhao(赵坤)1,5,§
摘要: Previous Monte Carlo simulations have shown that ordered tetratic phases can emerge in a dense two-dimensional Brownian system of rotationally asymmetric hard kites having 90° internal angles. However, there have been no experimental investigations yet to compare with these simulation results. Here, we have fabricated two types of micron-sized kites having internal angles of 72°-90°-108°-90° and 72°-99°-90°-99°, respectively, and we have experimentally studied their phase behavior in two-dimensional systems. Interestingly and in contrast to the Monte Carlo simulations, the experimental results show a phase sequence of isotropic fluid-hexagonal rotator crystal-square crystal as the area fraction φA increases for both types of kites. The observed square crystal displays not only a quasi-long-range translational order but also (quasi-)long-range 4-fold bond- and molecular-orientational order; these characteristics confirm that tetratic order can emerge even in dense Brownian systems of rotationally asymmetric particles. A model based on local polymorphic configurations (LPCs) is proposed to understand the origin of the square lattice order in these dense kite systems. The results in this study provide a new route to realize custom-designed self-assembly of colloids by controlling LPCs.
中图分类号: (Colloidal systems)