Paper Title
Self-Assembly of SDS and DTAB Mixed Surfactants

The micellar property of mixed surfactant systems, cationic (dodecyltrimethylammonium bromide) and anionic (sodium dodecylsulfate) surfactant of different molar ratios in aqueous medium has been studied by conductivity and surface tension measurements at T = (293.15, 298.15 and 303.15) K. The variation of concentration of dodecyltrimethylammonium bromide (DTAB) from 0.0001 to 0.03 mol∙L-1 with the presence of ̴ 0.01 mol∙L-1 sodium dodecylsulfate (SDS) while the concentration of SDS is varied from 0.001 to 0.015 mol∙L-1 with the presence of ̴ 0.005 mol∙L-1 DTAB. Hence the concentrations of cationic rich (DTAB-SDS) and anionic rich (SDS-DTAB) solutions were taken in the ratio of 3:1. The critical micelle concentrations (CMC) of cationic rich (DTAB-SDS) and anionic rich (SDS-DTAB) solutions were determined by the conductivity ( ) and surface tension ( ) measurements. The degree of ionization ( ), standard Gibb’s free energy of micellization ( 0 Gm ), standard enthalpy of micellization ( 0 m H ), the standard entropy of micellization ( 0 m S ) and heat capacity of micellization ( 0 m p  C ) are calculated by  data. The maximum surface excess concentration ( max  ), the area occupied per surfactant molecule ( min  ), surface pressure at the CMC ( cmc  ), free energy of adsorption ( 0 ads G ) and packing parameters (  ) were estimated from surface tension data. Keywords Critical micellization concentration∙ Thermodynamic parameters∙ Surface excess concentration∙ Area occupied by molecules∙ surface pressure∙ Mixed micelles