Stimulus-Responsive Heteroaggregation of Colloidal Dispersions: Reversible Systems and Composite Materials

Heteroaggregation is the aggregation of mixed particle systems where the colloidal particles may differ in charge, size and chemical composition. The phenomenon of heteroaggregation is of great relevance in industrial processes and the natural environment. This review will focus on binary heteroaggregation where at least one of the particles is a stimulus-responsive smart particle. Aggregation under various conditions of pH, temperature, light and relative concentration can be induced by the careful manipulation of any one or more of these environmental conditions during the heteroaggregation of smart particles. Stimulus response provides the potential for reversibility from an aggregated to a stable system and exceptional control over inter-particle interactions. The significant fundamental and applied studies that have made an impact in this area will be discussed.