How to model the interaction of charged Janus particles

Abstract

We analyse the interaction of charged Janus particles including screening e ects. The explicit interaction is mapped via a least square method on a variable number n of systematically generated tensors that re ect the angular dependence of the potential. For n = 2 we show that the interaction is equivalent to a model previously described by Erdmann, Kröger and Hess (EKH). Interestingly, this mapping is not able to capture the subtleties of the interaction for small screening lengths. Rather, a larger number of tensors has to be used. We nd that the characteristics of the Janus type interaction plays an important role for the aggregation behaviour. We obtained cluster structures up to the size of 13 particles for n = 2 and 36 and screening lengths κ −1 = 0.1 and 1.0 via Monte Carlo simulations. The in uence of the screening length is analysed and the structures are compared to results for an electrostatic-type potential and for multipole-expanded Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. We nd that a dipole-like potential (EKH or dipole DLVO approximation) is not able to su ciently reproduce the anisotropy e ects of the potential. Instead, a higher order expansion has to be used to obtain clusters structures that are identical to experimental results for up to N = 8 particles. The resulting minimum-energy clusters are compared to those of sticky hard sphere systems. Janus particles with a short-range screened interaction resemble sticky hard sphere clusters for all considered particle numbers, whereas for long-range screening even very small clusters are structurally di erent.

pH Dependence of Charge Multipole Moments in Proteins

“…It is in fact the orientational dependencies that are of particular importance for the local electrostatic interactions in numerous contexts, even when the coupling between pH, protonation states, and protein conformation is not taken into account. The results of our model should thus be relevant for the studies of interaction and assembly in ordered protein assemblies (such as a proteinaceous virus shell [42]), between charged Janus colloids [43], in the general context of patchy globular proteins, colloids, and polyelectrolytes [44][45][46][47][48][49], or possibly as a driving mechanism for local packing symmetry transitions in the proteinaceous capsid engineering in the presence of supercharged proteins [50].…”

Nonisotropic Self‐Assembly of Nanoparticles: From Compact Packing to Functional Aggregates

“…Monovalent, i.e. monopatchy, particles, usually called Janus particles [193], and their micelle-like or chain-like selfassemblies [193,194] will not be described in this paper because they cannot lead to higher dimension lattices.…”

Limiting the valence: advancements and new perspectives on patchy colloids, soft functionalized nanoparticles and biomolecules

“…97 A different modeling of charged Janus colloids was proposed to investigate the relation between the order of the multipolar expansion of the inter-particle potential and the resulting minimum-energy clusters. 98 In the context of globular proteins, a set of charged patchy particle models was introduced 99 to study the adsorption of such units on a polyelectrolyte chain 100 or on a polyelectrolyte brush layer. 101 These charged patchy models 99 have also been used to investigate the effect of multivalent electrolytes on the orientational correlations between the patchy units: it was shown that a careful choice of electrolytes could be used to steer the particle assembly.…”