Adsorption anomalies in a two-dimensional model of cluster-forming systems

Abstract

Adsorption on a boundary line confining a monolayer of particles self-assembling into clusters is studied by MC simulations. We focus on a system of particles interacting via competing interaction potential in which effectively short-range attraction is followed by long-range repulsion, mimicking the so called SALR system. For the chemical potential values below the order-disorder phase transition the adsorption isotherms were shown to undergo non-standard behavior, i. e. the adsorption exhibits a maximum upon structural transition between structureless and disordered cluster fluid. In particular, we have found that the adsorption decreases for increasing chemical potential when (i) clusters dominate over monomers in the bulk, (ii) the density profile in the direction perpendicular to the confining line exhibits an oscillatory decay, (iii) the correlation function in the layer near the adsorption wall exhibits an oscillatory decay in the direction parallel to this wall. Our report indicates striking differences between simple and complex fluid adsorption processes.

Hard core-soft shell particles near repulsive interfaces: interplay between adsorption, aggregation and diffusion

“…With this, we could connect adsorption, clustering and diffusion with the competition between the length scales of SALR. In fact, the correlation between maximum in the adsorption and clustering agrees with the recent work by Bildanau and co-workers for 2D systems, 47 and our results provide information regarding the connection with the diffusion behavior at the interface and the competition between the scales.…”

“…[37][38][39][40][41][42] There are a plenty of works exploring the behavior of confined SALR systems in recent times: Almarza et al have inspected the template-assisted pattern formation in monolayers of particles by Monte Carlo simulations in a lattice gas generic model; 25,43 Litniewski and Ciach have analyzed the general features of adsorption phenomena in dilute systems with particles self-assembling into small clusters; 44,45 more recently, Panagiotopoulos et al have scrutinized properties of lamellar structures formed by an SALR fluid in equilibrium and non-equilibrium conditions by machine learning; 46 Bilnadau et al investigated the cluster formation effect on adsorption phenomena they have laid down deviation in the shape of the adsorption isotherm in comparison with simple fluids. 47 Though, according to the authors' knowledge, no relationship between aggregation, adsorption and dynamic management was listed in these SALR colloids at interfaces. In this work, we have looked over the behavior of a SALR system confined by two types of plates: rough and flat, and we've explored the distinctness of adsorption isotherms, lateral structuring (by means of the lateral radial distribution function) and the dynamic behavior of the system in order to answer the question: how the surface smoothness influence the adsorption in systems shaped by competitive interactions?…”

Adsorption in Mixtures with Competing Interactions

“…At this crossover, the specific heat takes a maximum [13]. It turned out that the adsorption as a function of the chemical potential takes a maximum at this crossover as well [14], and decreases for increasing chemical potential in the clusterdominated system. This anomalous behavior of adsorption originates from repulsion between the clusters.…”

“…Phenomena associated with adsorption on solid surfaces have been studied for decades for systems ranging from noble gases to liquid crystals and polymers [1][2][3][4]. Still, adsorption in systems with competing interactions, such as short-range attraction and long-range repulsion (SALR) [5][6][7][8][9][10][11][12], have attracted attention only recently [13,14]. The long-range repulsion between the particles originates typically from screened electrostatic interactions, and the attraction is often mediated by complex solvents.…”

Adsorption time scales of cluster-forming systems

“…2D lattice models of the systems with competing interactions are widely studied due to possibility understanding many their fundamental features with comparatively restricted computational facilities. To date, main efforts were concentrated on investigating microphase separation and pattern formation in bulk [32][33][34][35][36][37] and confined [38][39][40][41] equilibrium systems. Kinetic properties were rarely addressed.…”