Dispersant

Synonyms

Dispersants for preparation of solid; Liquid dispersions and their stabilization

Definition

A dispersant is a surface-active substance that is added to disperse a solid powder into a liquid and maintain the particles in a dispersed state (without any aggregation). The dispersant performs several functions: (a) lowers the surface tension of the liquid to aid wetting of the powder, (b) adsorbs at the solid/liquid interface to lower the solid/liquid interfacial tension, (c) lowers the contact angle of the liquid on the solid surface (zero contact angle is very common), (d) helps to break up the aggregates and agglomerates as well as in subdivision of the particles into smaller units, and (e) stabilizes the particles formed against any aggregation (or rejoining). All dispersing agents are surface active, and they can be simple surfactants (anionic, cationic, zwitterionic, or nonionic), polymers, or polyelectrolytes. The dispersing agent should be soluble (or at least dispersible)...