Densest versus jammed packings of two-dimensional bent-core trimers

Abstract

We identify the maximally dense lattice packings of tangent-disk trimers with fixed bond angles (θ = θ0) and contrast them to both their nonmaximally-dense-but-strictly-jammed lattice packings as well as the disordered jammed states they form for a range of compression protocols. While only θ0 = 0, 60 • , and 120 • trimers can form the triangular lattice, maximally-dense maximallysymmetric packings for all θ0 fall into just two categories distinguished by their bond topologies: half-elongated-triangular for 0 < θ0 < 60 • and elongated-snub-square for 60 • < θ0 < 120 •. The presence of degenerate, lower-symmetry versions of these densest packings combined with several families of less-dense-but-strictly-jammed lattice packings act in concert to promote jamming.

Densest versus jammed packings of bent-core trimers

“…Here the 3/2 reflects the fact that the gap-layer density is 50% higher for families III and V than it is for families I and II. Similar relations hold for 2D systems [21]. Additional insight into the structure of these maximally-dense crystals can be gained by examining the topology of their bond/contact network and trends in their β 2 (θ 0 ).…”

“…In particular, 3D straight trimers (θ 0 = 0) can closepack yet produce the global minimum in φ J (θ 0 ). This differerence arises partially from differences in crystallizability; 2D θ 0 = 0 trimers form MJ states possessing a moderate degree of crystalline order [21], whereas in 3D their MJ states are maximally disordered as discussed above. Third, in both 2D and 3D compactness and symmetry promote dense packing, i.e.…”

“…Solid curves show φJ (θ0) for quasistatic compression while dashed curves show φmax(θ0). The 2D results are from Ref [21]…”

Engineering porous two-dimensional lattices via self-assembly of non-convex hexagonal platelets

“…Examples of non-convex particles confined in 2D have also been studied experimentally and in simulations. 28,[41][42][43][44][45][46] In this work, a generic coarse-grained model of non-convex hexagonal platelets is used to study the effects of both nonconvexity of the particles and interparticle interactions on the phase behaviour of the structures, with particular emphasis on targeting well-defined porous ordered structures.…”

Factors influencing thermal solidification of bent-core trimers

“…Refs. [10,11] reported the densest packings of 2D and 3D tangent-sphere trimers and contrasted them to the jammed packings they form under dynamic athermal compression.…”