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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

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Functional polymers are used as additives in the formulation of fuels either for their detergency properties or for retaining cold weather operability. Examples of recent research work aimed at a better understanding of the physico‐chemical phenomena involved and at the design and synthesis of new polymers are described. One phenomenon common in most applications is the adsorption of the polymers on various surfaces (gums, soot, metal walls, paraffin crystals). In the case of chain‐end functional polymers, strong affinity of the functional groups for the surface sites is required in order to reach the high adsorption densities that allow optimum stabilization properties. This can be achieved by a correct choice of the functional group (of its polymeric nature, having a primary amino group that will strongly interact with surface sites) or by the design of the macromolecular architecture. In the case of very complex systems (eg the crystallization of paraffins in diesel fuel), the selection of relevant experimental models allows investigations into mechanisms at a microscopic level. Such studies would obviously not be possible on the diesel fuel itself, which is nevertheless the only really representative sample. Copyright © 2004 Society of Chemical Industry