Professor Lutful Bhuiyan, University of Puerto Rico Piedras, is supported by a grant from the Theoretical and Computational Chemistry Program to continue his theoretical research on the influence of collective interactions between colloidal particles on colloidal stability. Modified Poisson-Boltzmann (MPB) theory will be used to investigate the importance of collective effects of all the charged species of a colloidal solution on the interaction between two colloidal particles. Four specific goals of the research are: 1) to adapt the MPB equation to the situation where one or more of the species is the colloidal particle so all interactions are treated on an equal footing; 2) to study the interaction between colloidal particles on concentration, size, and charge of both the colloidal particle and the simple ions; 3) determine the effect of steric interaction with solvent molecules on colloid-colloid interactions; and 4) to consider further development of the MPB approach. A fundamental understanding of the nature of interparticle forces in highly interacting colloidal dispersions does not as yet exist. It is still not well understood what keeps charged colloidal particles dispersed in water from coagulating. Because of their unusual physical properties colloidal materials have found widespread industrial use, and may in the future have important device applications. In order to design materials with desired properties, it is necessary to understand the detailed atomic level description of the strong interactions between these charged particles in solution. Bhuiyan's research is directed at a basic theory to explain these properties.
