Control of the morphology of waterborne nanocomposite films

Nanocomposite materials are prepared by drying a mixed colloidal suspension of film-forming latex and silica. The dispersion state of the silica particles in the dry film controls the properties. We describe, with the help of some examples, how the colloidal stability of the particles in the mixed suspension dictates the final morphology of the dry film. Next, some recent work aimed at controlling the morphology by means of formulation additives is described. Such additives are either surfactants or polymer dispersants (block copolymers) which stabilize the particles (latex and/or silica) in the drying suspension. As a result of the mixing-and-drying preparation process, suitable additives are necessarily different from the conventional dispersants used in the formulation of composites prepared by means of melt-processing. Copyright © 2004 Society of Chemical Industry