Micellar adsorption from aqueous solutions of rheological additive IVP-325 on carbon black and titanium dioxide samples

The adsorption of IVP-325 additive, which is a deflocculating agent to prevent sedimentation of organo-dilutable water-containing systems from solutions in water, was studied on samples of carbon black and titanium dioxide. This anionic surfactant (surfactant), which does not contain organic solvents, has a wetting, antiflotation and dispersing effect on pigment particles and fillers. The surface tension isotherm of the IVP-325 additive from water has 2 stages corresponding to the formation of the first (KKM₁ ) and second (KKM₂ ) critical concentrations of micelle formation. With increasing concentration, surfactant molecules spontaneously assemble into stable spherical aggregates (Hartley micelles), then acquire the shape of an ellipsoid, then a cylinder and other shapes. The surface activity of the additive in relation to water at concentrations <KKM₁ is described by the Shishkovsky equation. The standard Gibbs micelle formation energy and the equation of state of the adsorption film are determined. Experimental isotherms for the adsorption of IVP-325 additives from water on carbon black samples K-354 and TU-339 are two-stage and have an S-shaped concave shape. This indicates both a strong competing adsorption of solvent (H2O) and the formation of micellar structures in the adsorption layer on the surface of the particles of the carbon black under study. The experimental adsorption isotherm of the IVP-325 additive from H2O on a sample of titanium dioxide R-838 also has an S-shaped concave two-stage shape, although not as clearly defined as in the case of carbon black. This indicates a strong competing adsorption of water, however, the amount of adsorption of the additive is several times less than in the case of samples K-354 and TU-339.

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