Sedimentation of colloidal plate-sphere mixtures and inference of particle characteristics from stacking sequences

Abstract

We investigate theoretically the effect of gravity on a plate-sphere colloidal mixture by means of an Onsager-like density functional to describe the bulk, and sedimentation path theory to incorporate gravity. We calculate the stacking diagram of the mixture for two sets of buoyant masses and different values of the sample height. Several stacking sequences appear due to the intricate interplay between gravity, the sample height, and bulk phase separation. These include the experimentally observed floating nematic sequence, which consists of a nematic layer sandwiched between two isotropic layers. The values of the thicknesses of the layers in a complex stacking sequence can be used to obtain microscopic information of the mixture. Using the thicknesses of the layers in the floating nematic sequence we are able to infer the values of the buoyant masses from the colloidal concentrations and vice versa. We also predict new phenomena that can be experimentally tested, such as a nontrivial evolution of the stacking sequence by increasing the sample height in which new layers appear either at the top or at the bottom of the sample.

References in corpus (19)

• Predicting phase equilibria in polydisperse systems
• Hard-body models of bulk liquid crystals
• Density functional theory for colloidal mixtures of hard platelets, rods, and spheres
• Multiple reentrant glass transitions in confined hard-sphere glasses
• Is there a reentrant glass in binary mixtures?
• Floating nematic phase in colloidal platelet-sphere mixtures
• Phase stacking diagram of colloidal mixtures under gravity
• Fabrication of colloidal Laves phases via hard tetramers and hard spheres: bulk phase diagram and sedimentation behaviour
• Depletion potential in colloidal mixtures of hard spheres and platelets
• Defying the Gibbs Phase Rule: Evidence for an Entropy-Driven Quintuple Point in Colloid-Polymer Mixtures
• Bulk and wetting phenomena in a colloidal mixture of hard spheres and platelets
• Liquid crystalline phases and demixing in binary mixtures of shape-anisometric colloids
• Gravity-induced phase phenomena in plate-rod colloidal mixtures
• Tracking three-phase coexistences in binary mixtures of hard plates and spheres
• Bulk fluid phase behaviour of colloidal platelet-sphere and platelet-polymer mixtures
• The role of sample height in the stacking diagram of colloidal mixtures under gravity
• Depletion-driven four-phase coexistences in discotic systems
• Sedimentation stacking diagrams of binary mixtures of thick and thin hard rods
• Sedimentation stacking diagram of binary colloidal mixtures and bulk phases in the plane of chemical potentials

Cited by in corpus (4)

• Comparative study of force-based classical density functional theory
• A new method for reactive constant pH simulations
• Sedimentation path theory for mass-polydisperse colloidal systems
• Effect of sample height and particle elongation in the sedimentation of colloidal rods