Surfactant adsorption from aqueous solutions

Dispersant and surfactant additives, although used in minor amounts, exert a major influence in latex paints, controlling, for example, long‐term and freeze‐thaw stability in the can, application properties, and the opacity, gloss, and scrub resistance of the dry film. In such complicated multiphase systems, exact knowledge of the role played by these dispersants and surfactants and their distribution is vital to optimum formulation. For instance, the amount of dispersant required to ensure pigment deaggregation during ‘grinding’, and to ensure stability of the resultant mill base, has been one of the principal concerns of paint formulators. Several techniques to determine this have been reported‐i.e., Daniels Flow Point measurements in resin or dispersant solutions, or Brookfield viscosity measurements at various dispersant levels after dispersion, and titration of pigment with dispersant solutions with a Brabender Plastigraph‐type sigma blade mixer.