Surface chemistry and rheology of polysulfobetaine-coated silica.

We have measured the viscosity of suspensions of colloidal silica particles (d = 300 nm) and the properties of silica surfaces in solutions of a polymer consisting of zwitterionic monomer groups, poly(sulfobetaine methacrylate), polySBMA. This polymer has potential use in modifying surface properties because the polymer is net uncharged and therefore does not generate double-layer forces. The solubility of the polymer can be controlled and varies from poor to good by the addition of sodium chloride salt.