Dynamic simulations of many-body electrostatic self-assembly

Abstract

Two experimental studies relating to electrostatic self-assembly have been the subject of dynamic computer simulations, where the consequences of changing the charge and the dielectric constant of the materials concerned have been explored. One series of calculations relates to experiments on the assembly of polymer particles that have been subjected to tribocharging and the simulations successfully reproduce many of the observed patterns of behaviour. A second study explores events observed following collisions between single particles and small clusters composed of charged particles derived from a metal oxide composite. As before, observations recorded during the course of the experiments are reproduced by the calculations. One study in particular reveals how particle polarizability can influence the assembly process.This article is part of the theme issue 'Modern theoretical chemistry'.

Granular ionic crystals in a small nutshell

“…It may be speculated that polarization helps to stabilize the contacts of the like-charged dielectric spheres. 8,29 The observed compression is surprisingly stronger at top of the packing than at the bottom. This is most likely caused by the lateral dilation that has to accompany the vertical compression.…”

“…The ordered structures that emerge upon vibration of binary mixtures of granular particles in two-dimensional horizontal experiments had been studied in various publications. [2][3][4][5][6][7][8] The emergence of three-dimensional ordered structures, in contrast, has only been observed once in a study on humidity effects and segregation of vibrated Teflon (PTFE) and nylon (PA) spheres, 9 to the best of the authors' knowledge. This minimal number of observed three-dimensional ordered structures caused by opposite triboelectric charging suggests existence of a mechanism that suppresses emergence of order by charging.…”

An integral equation formulation of the N-body dielectric spheres problem. Part II: complexity analysis

“…Let us point out however that from a practical point of view, this additional constraint is not too restrictive since it covers the two cases which typically arise in physical applications: The case of weakly polarisable particles embedded in a highly polarisable solvent and the case of highly polarisable particles embedded in a weakly polarisable medium. Examples of the former include teflon, PMMA, polyethylene or polypropylene particles in water (see [37]). Examples of the later include a wide range of Titanium-based oxides or certain highly polarisable polymer particles in air (see [45]).…”

Self‐Assembly Behavior of Oppositely Charged Inverse Bipatchy Microcolloids

“…Such connections could arise from the complexity of subtle changes in the density of charge residing on the surface of each particle as a consequence of charge‐induced polarization effects, as seen in many‐body systems. [ 28,29 ] An attraction between objects carrying the same sign of charge is even possible in the pairwise interaction and results from a mutual polarization of charge density close to the region where they are in contact. [ 28 ] To generate an attractive interaction between like‐charged objects it is not only necessary for one object with a high charge density to polarize another, but there has to be a reciprocal displacement of density on the second object, too.…”