Depletion-driven crystallization of cubic colloids sedimented on a surface

Abstract

Cubic colloids, sedimented on a surface and immersed in a solution of depletant molecules, were modeled with a family of shapes which smoothly varies from squares to circles. Using Wang-Landau simulations with expanded ensembles, we observe the formation of rhombic lattices, square lattices, hexagonal lattices and a fluid phase. This systematic investigation includes locating transitions between all combinations of the three lattice structures upon changing the shape, and transitions between the fluid and crystal upon changing the depletant concentration. The rhombic lattice deforms smoothly between square-like and hexagonal-like angles, depending on both the shape and the depletant concentration. Our results on the effect of the depletant concentration, depletant size, and colloid shape to influence the stability of the fluid and the lattice structures may help guide experimental studies with recently synthesized cubic colloids.

Assembly of multi-flavored two-dimensional colloidal crystals

“…Specific details of our implementation can be found in ref. 50 and 51. In each simulation, we used single particle displacement moves, identity swaps, geometric cluster moves, 52,53 and incremental changes to λ A,B which occurred in a ratio of 5000 : 5000 : 10 : 1, respectively.…”

FEASST: Free Energy and Advanced Sampling Simulation Toolkit

“…The Free Energy and Advanced Sampling Simulation Toolkit (FEASST) is a free, open-source, modular program to conduct molecular and particle-based simulations with Metropolis, Wang-Landau and Transition-Matrix Monte Carlo methods [1][2][3][4][5][6][7]. FEASST is implemented in C++ and may be imported as a module within Python 2 or 3.…”

Tabular Potentials for Monte Carlo Simulation of Supertoroids with Short-Range Interactions

“…Due to the development of new techniques for nanoparticle construction [1][2][3][4][5], recent years have seen rapid growth in the use of anisotropic colloids [6,7]. Colloids have become an appealing base for self-assembly studies because the interaction, both attractive and repulsive, between particles can be controlled by manipulating the properties of the individual particles, such as the particle anisotropy [8][9][10][11]. This push for the development of more exotic types of colloids has caused an increased demand for simulations that accurately and efficiently predict the system behavior over a range of thermodynamic conditions.…”

“…Expansion of the model to include porous, concave [15][16][17][18] shapes would allow the examination of systems relevant for drug delivery [17,[19][20][21], optics [17,19], catalysis [22], and photonics [20,21]. Existing models also focus on single-component systems [9,18], rather than multicomponent systems. While existing algorithms aim to efficiently compute the overlap of hard superquadrics during the many-particle simulation [23], computational time may be further reduced by use of tabular potentials.…”