INFLUENCE OF ELECTROKINETIC POTENTIAL ON ADSORPTION OF CATIONIC SURFACTANTS

Electrokinetic potential plays an important role in textile wet proces ses such as dyeing, finishing, and washing. The zeta potential of cott on fiber in aqueous solution is negative and influences adsorption of surfactants having the same or opposite electrical sign. The influence of zeta potential of cotton fibers on the adsorption of two cationic surfactants, dodecyltrimethyl ammonium chloride and distearyldimethyl ammonium chloride, at pH 4, 7, and 9 was studied. Cotton threads were mercerized in NaOH solutions in a slack state. Mercerization causes ch anges in fine structure, morphology, and conformation of cellulose cha ins and lowers the negative electrokinetic potential of cotton fibers. Based on this phenomena, cotton threads were treated in NaOH solution s of various concentrations resulting in samples with different degree s of mercerization and different electrokinetic potential. The amount of adsorbed surfactant on cotton fibers was quantitatively determined from the surfactant content in solution by the two-phase titration met hods. The electrokinetic potential was measured using the streaming cu rrent method by EKA. The zeta potential was calculated from the Helmho ltz-Smoluchowski equation.