Wetting is the first step in the dispersion process. The air that surrounds the solid particles in an agglomerate must be substituted by liquid. Wetting will take place when the surface tension of the liquid is low compared to the surface energy of the solid particles. Wetting will not occur when the surface tension of the liquid is too high.
Dispersing
Solid particles attract each other. For this reason, energy is needed to separate the particles from each other in the second step of the dispersion process. Also, solid particles must be stabilised after they have been separated from each other. The particles will move to each other and glue together again when particle-particle repulsion is insufficient. The spontaneous process of gluing together of solid particles in a liquid is called flocculation. The functionality of a dispersant is to prevent flocculation. Dispersants do their job because the molecules adsorb on the solid-liquid interface and assure repulsion between the particles.
We offer a comprehensive range of wetting and dispersing additives (low and high molecular weight) for solvent and water-based systems to help you optimize your dispersions in coatings, printing inks and plastics (composite).
