GOALI: Colloid Stability and Transport in Solutions of Nonadsorbing Polyelectrolytes

Yale University, New Haven CT

Investigators

Abstract

Abstract CTS-9912098 J. Walz, Yale University The proposed effort is to explore the effect of nonadsorbing polyelectrolytes on the stability of a dispersion of charged particles. The application of this knowledge would be many. For instance, the fractionation of field flows could be enhanced by the presence of nonadsorbing polyelectrolytes. Central to this study is the determination of interparticle forces (as compared to electrostatic and van der Waals), as they control the stability of polyelctrolyte-colloid systems. Several directions would be investigated: 1) The influence of increased polyelectrolyte concentration on the appearance of flocculation followed, in some cases, by restabilization. A model will hopefully be able to account for a comprehensive range of experimental measurements. 2) Polydispersity and charge heterogeneity will be correlated with the existing interparticular force balance. This modeling will be established with the help of optical techniques (e.g. total internal reflection microscopy). 3) Special attention will be given to an important industrial process, viz. the interaction of titanium oxyde particles with various types of stabilizers. In particular, surface-particle force profiles will be determined with an atomic force microscope. Flocculation rates will be obtained by acoustic spectrometric methods. 4) The role of rod-like geometry in particle interaction will be investigated. Validation will be tested on well-characterized DNA segments. 5) The effect of nonadsorbing polyelectrolytes on particle transport processes in the vicinity of surfaces will be tested and modeled. Flow fields in or near porous media is of fundamental interest to industrial design.