MICELLAR SOLUTION OF TETRADECYLTRIMETHYLAMMONIUM BROMIDE CETYLTRIMETHYLAMMONIUM BROMIDE MIXTURES

The micellar solution of two cationic surfactants cetyltrimethylammoni um bromide (CTAB) and tetradecyltrimethylammonium bromide (TTAB) mixtu res was investigated. Their miscibility was determined by measuring th e surf ace tension of the aqueous solution of the mixtures at variable composition. mole fraction of CTAB. The results also indicated that C TAB and TTAB molecules mix slightly nonideally in the micelle at lower mole fraction of CTAB. In addition, the rate of change of the cmc val ue is nearer to the cmc value of the longer, hydrocarbon chain molecul e (CTAB). Therefore, it was concluded that the longer hydrophobic grou p of CTAB is geometrically favorable for the micelle formation.