Inorganic Suspensions Using Well-Defined Copolymeric Stabilizers

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This research concerns a fundamental study of the effect of low levels of copolymers on the properties of aqueous colloidal suspensions. Systematically designed, novel, block and graft copolymers with narrow molecular-weight distributions of each block will be synthesized and mixed with selected colloidal particles having narrow-size distributions. The effect of the adsorbed copolymers on the stability and properties of the suspensions will be measured by techniques including rheology and light scattering. The particle concentrations will range from dilute to highly concentrated in order to study the critical effect of particle concentration on suspension microstructure. Steric stability is provided by a water-soluble tail segment on the copolymer that is anchored to the particle by an adsorbed hydrophobic head block. The effectiveness of the water-insoluble block as an anchor will be studied as a function of chemical structure. It is anticipated that specific interactions between the particle surface and the adsorbed copolymer will be of particular importance in aqueous, hydrogen-bonding media. In addition to the steric stabilization mechanism, electrostatic stabilization is also important for the case of charged tail segments. The particles to be studied will be well-characterized inorganic materials, primarily SiO2, Al2O3, SiC, and Si3N4.