Effect of molecular architecture of long chain fatty acids on the dispersion properties of titanium dioxide in non-aqueous liquids

Abstract

The effect of varying chain length and chain branching on the adsorbed layer thickness of oligoesters on titania in non-aqueous solvents has been studied and related to the degree of flocculation of the dispersions using viscometry.The oligoesters were a series of monodisperse condensates of 12-hydroxystearic acid, up to the pentamer. Also, a series of branched esters in which the degree of branching was varied systematically was studied. The latter consisted of the valeric esters of mono-, di- and tri-hydroxystearic acid.It was found that the thickness of the adsorbed layer was not necessarily the criterion for good dispersion stability, but a complex function of surface concentration. This was dependent on main chain length, the size, position and number of branches and the solvency of the medium.