Curvature-assisted self-assembly of Brownian squares on cylindrical surfaces

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:605

Article

Liu, Huaqing¹  Zong, Yiwu¹  Zu, Mengjie²  Mason, Thomas G.^3,4  Ye, Fangfu^2,5,6  Zhao, Kun^1,7 

[1] Tianjin Univ, Sch Chem Engn & Technol, Minist Educ, Key Lab Syst Bioengn, Tianjin 300072, Peoples R China

[2] Univ Chinese Acad Sci, Wenzhou Inst, Wenzhou 325001, Peoples R China

[3] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA

[4] Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA

[5] Chinese Acad Sci, Beijing Natl Lab Condensed Matter Phys, Inst Phys, Beijing 100190, Peoples R China

[6] Chinese Acad Sci, Lab Soft Matter & Biol Phys, Inst Phys, Beijing 100190, Peoples R China

[7] Tianjin Univ, Phys Dept, Tianjin 300072, Peoples R China

关键词: Colloidal squares;    Cylindrical surface;    Self-assembly;    Curvature;    Entropy;   

DOI  :  10.1016/j.jcis.2021.07.123

来源: Elsevier

【 摘 要 】

Hypothesis: We hypothesize that curved surfaces, including cylindrical surfaces, which go beyond prior experiments using flat surfaces, can significantly influence and alter the phase behavior and self-assembly of dense two-dimensional systems of Brownian colloids. Experiments: Here, we report a first experimental study regarding the self-assembly of Brownian square platelets with an edge length L = 2.3 mu m on cylindrical surfaces having different curvatures; these plate-lets are subjected to a depletion attraction in order to form a monolayer above the cylindrical surface, yet have nearly hard interactions within the monolayer. Simulations are also performed to confirm and explain the experimental observations. Findings: Phase diagrams as a function of curvature are determined experimentally. Interestingly, hexagonal rotator crystal structures are observed for tubes having radii > 10.9L, but a tetratic phase is seen instead for the 10.9L tube at the corresponding platelet area fractions. We show that this transition is caused by the curvature-induced orientation-dependence of the depletion attraction between the squares and the underlying cylindrical surface. Brownian dynamics simulation results confirm the experimental observations and also illustrate helical structures formed by squares packing on cylinders. Our results demonstrate a way towards control over the self-assembly of anisotropic particles through curvature and depletion-attraction-induced orientational confinement. (C) 2021 The Author(s). Published by Elsevier Inc.

【 授权许可】

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