CONCENTRATION EFFECTS IN BULK COLLOIDS AND INTERFACIAL PHASES (ADSORPTION, CLUSTERING, MEMBRANES (POROUS), ZEOLITES, ADHESIVE POTENTIAL).

摘要

Three problems concerning the consequences of particle interactions in colloidal fluids and interfacial phases are undertaken: the aggregation of particles in bulk phases, the thermodynamics of particulate systems confined within narrow pores and cavities (such as those found in porous membranes), and the thermodynamics of a monolayer adsorbed onto a small surface.; Particle interaction effects on a structural, thermodynamic, or transport property can be adequately studied by developing an expansion for that property as a power series in particle concentration. Statistical mechanics is used to develop these concentration expansions and, in the study of monolayers, Scaled Particle Theory and Monte Carlo simulation are applied.; The clustering behavior of a system of particles which interact via the adhesive-sphere potential is examined, and the first non-trivial exact results for this model are obtained. Previous studies on the aggregation and percolation behavior of these particles are limited to the average cluster size, but this work provides detailed results for the suspension microstructure, such as the distribution of cluster sizes and shapes. In addition we find singularities in the structure of a fluid of adhesive particles, a characteristic previously unknown for the two- and three-dimensional models.; Particle adsorption in micropores is analyzed with the following theoretical model: an adhesive particle-wall interaction; hard-sphere like particle-particle interactions; and two micropore geometries, that of a slit and a cylindrical pore. Particle interactions in an adsorbed two-dimensional layer enhance the partitioning of solute particles between a microporous phase and a bulk phase, to a greater extent than the enhancement caused by interactions between particles residing in the micropore fluid.; The spreading pressure and chemical potential of a finite-sized, spherical monolayer of hard particles are obtained, and the results are applied to model adsorbate-adsorbate interactions inside zeolite molecular sieves.