Effect of Glycol Additives on CMC of Imidazolium Cationic Surfactants

: Changes in critical micelle concentrations (cmc’s) of six cationic surfactants 1-(decyl oxy carbonyl methyl)-3-methyl imidazolium bromide, 1-(dodecyl oxy carbonyl methyl)-3-methyl imidazolium bromide, 1-(tetradecyl oxy carbonyl methyl)-3-methyl imidazolium bromide, 1-(decyl oxy carbonyl methyl)-3-methyl imidazolium chloride, 1-(dodecyl oxy carbonyl methyl)-3-methyl imidazolium chloride, 1-(tetradecyl oxy carbonyl methyl)-3-methyl imidazolium chloride having different counter ions have been investigated by electrical conductivity and tensiometric measurements. It was found that increase in concentration of ethylene glycol, diethylene glycol and triethylene glycol added to surfactant aqueous solution caused an increase in cmc’s of surfactants, provoked by the decrease in interfacial Gibbs energy. There is decrease in wavelength and increase in absorption with the increase in additive concentration. The effect on cmc was maximum in case of triethylene glycol.