Formation of lamellar structures from spherical particles

Abstract

We report disorder to lamellar transition in a system of spherically symmetric particles where the interparticle potential consists of a short-ranged attraction and a longer-ranged repulsion. The system provides a simplified model for aqueous dispersions of colloidal particles and globular proteins that may exhibit stable/metastable clusters or microscopic phases. By using a non-mean-field density functional theory, we predict that under appropriate conditions, a lamellar phase with alternating condensed and dilute layers of particles is thermodynamically more stable than a uniform disordered phase at the same temperature and molecular number density. Formation of the lamellar structure may prohibit the macroscopic fluid-fluid phase transition. At a given condition, the width of the condensed lamellar layers increases with the overall particle density but the trend is opposite for the dilute lamellar layers. A minimal lamellar periodicity is obtained when the condensed and dilute layers have approximately the same thickness.

Density Functional Theory for Adsorption of Gas Mixtures in Metal−Organic Frameworks

“…Toward this end, remarkable advances have been achieved on the basis of statistical mechanics for example, density functional theory (DFT) and integral equation theory. In particular, DFT turns out to be robust in the study of inhomogeneous fluids. − In the past a few decades, a large number of various versions of DFT have been proposed. − …”

Fluid of discs with competing interactions

“…The model given by Equation (2) in dimension d ¼ 2 was studied by Imperio and Reatto [4][5][6]. A slightly modified version of this model in d ¼ 3, where the exponential functions were replaced by Yukawa interactions, was studied Reatto and colleagues [8][9][10] and also inspired studies by Archer et al [11,12] and by Li et al [13].…”

Microphase separations of the fluids with spherically symmetric competing interactions

“…A few studies regarding the influence of confinement on the phase behavior of a competing system has been reported in the slit-type pore. 9,11,[13][14][15] More recently, Kim et al 15 had shown that the periodic spacing of the modulated structure is commensurate with the periodicity of modulation in the particle density distribution and the cluster phase only appears when the periodic spacing is greater than the slit width. Here, one of the important questions we consider is how the geometry of the pores, the size of the pores, and the competing interaction affect the structure and phase behaviors of a confined competing system.…”

“…The competing system is an interesting model, which has an attractive interaction at a short distance and a repulsive one at a long distance. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Such a competing system gives rise to various microphase separated phases including the cluster phases. Many studies have been made to understand microphase formations induced by the competing interactions in the bulk and confined phases.…”

“…However, the general behavior of a competing system under confinement has received very limited attention. 9,11,[13][14][15] In general, the confinement induces new pattern morphologies, which might not appear at all in the bulk. It also modifies the pattern morphologies by the geometrical symmetry of the pores.…”