A comparative study of Critical Micelle Concentration (CMC) and Free Energy of Micellization of cationic surfactant and anionic surfactant in different composition of methanol-water mixed solvent media by conductometric method at 308.15 K

Abstract

Precise measurements on the specific conductivity of cationic surfactant (Dodecyltrimethyl ammonium bromide) and anionic surfactant (Sodium Dodecyl Sulphate) in methanol water mixed solvent media containing 0.1, 0.2 and 0.3 volume fractions of methanol are reported at 308.15 K. Specific conductivities of Dodecyltrimethyl ammonium bromide and Sodium Dodecyl Sulphate increase with increase in concentration and decrease with increase in the volume fractions of methanol. Critical micelle concentration (cmc) increases with increase in volume fraction of methanol in case of both surfactants. Free energy of micellization (ΔGºm) has been calculated. Increase in cmc with increase in volume fractions of methanol has been explained in terms of breaking of structure of water due to co-solvent effect.Keywords: Critical micelle concentration; methanol-water mixed solvent media; Specific conductivity; Dodecyltrimethylammonium Bromide; Sodiumdodecyl SulphateDOI: http://dx.doi.org/10.3126/bibechana.v8i0.4883 BIBECHANA 8 (2012) 37-45