Hard superellipse phases: particle shape anisotropy & curvature

Journal Article · 16 January 2022 · Soft Matter

DOI: https://doi.org/10.1039/d1sm01523k · OSTI ID:1844043

Torres-Díaz, Isaac  ^[1]; Hendley, Rachel S.  ^[2]; Mishra, Akhilesh ^[2]; Yeh, Alex J. ^[2]; Bevan, Michael A.  ^[2]

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1. Johns Hopkins Univ., Baltimore, MD (United States); Univ. of Alabama, Huntsville, AL (United States); Johns Hopkins University
2. Johns Hopkins Univ., Baltimore, MD (United States)

In this work, we report computer simulations of two-dimensional convex hard superellipse particle phases vs. particle shape parameters including aspect ratio, corner curvature, and sidewall curvature. Shapes investigated include disks, ellipses, squares, rectangles, and rhombuses, as well as, shapes with non-uniform curvature including rounded squares, rounded rectangles, and rounded rhombuses. Using measures of orientational order, order parameters, and a novel stretched bond orientational order parameter, we systematically identify particle shape properties that determine liquid crystal and crystalline phases including their coarse boundaries and symmetry. We observe phases including isotropic, nematic, tetratic, plastic crystals, square crystals, and hexagonal crystals (including stretched variants). Our results catalog known benchmark shapes, but include new shapes that also interpolate between known shapes. Our results indicate design rules for particle shapes that determine two-dimensional liquid, liquid crystalline, and crystalline microstructures that can be realized via particle assembly.

• Research Organization: Johns Hopkins Univ., Baltimore, MD (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0017892
• OSTI ID: 1844043
• Journal Information: Soft Matter, Journal Name: Soft Matter Journal Issue: 6 Vol. 18; ISSN 1744-683X
• Publisher: Royal Society of ChemistryCopyright Statement
• Country of Publication: United States
• Language: English