PROPERTIES OF COMPLEXES AND PARTICLES OF GELATIN WITH IONIC SURFACTANTS

The properties of soluble gelatin-ionic surfactant complexes and insol uble particles were evaluated. It was found that colloidal particles o f gelatin A - cationic surfactant (dodecyltrimethylammonium bromide, D TAB, and cetyltrimethylammonium bromide, CTAB) were formed. Binding is otherms showed that these particles are obtained above the CMC of each surfactant, while cooperative binding takes place. Surface tension me asurements conducted for both gelatin/DTAB and gelatin/anionic surfact ant, SDS (sodium dodecyl sulfate) showed a break in the curve describi ng surface tension vs number of bound surfactant molecules, (nu) at co ncentrations below the CMC of each surfactant alone. This break, which is attributed to CMC 1, is observed at the same number of bound surfa ctant molecules nu similar to 2 for both gelatin/surfactant couples. C ontact angle measurements showed that the maximal hydrophobicity of th e gelatin-surfactant particles is obtained at the same concentration r ange in which the precipitation occurs. It was also found that the hyd rophobicity of gelatin-SDS particles, is higher than that of the gelat in-cationic surfactants, due to a different composition of the resulti ng particles. The zeta potential of the particles indicated charge neu tralization and even charge reversal for gelatin-CTAB at high surfacta nt concentration.