Polymer effect on thermodynamic and interfacial properties of cationic and anionic surfactants in aqueous solutions

Micellization and adsorption at liquid-air interface were investigated for mixture of cethyltrimethylammonium bromide (CTAB) and polyethyleneglycole (PEG), sodiumdodecylsulfate (SDS) and polyethyleneglycole (PEG) at different temperatures by surface tension and viscometry measurements. The data based on plotting of surface tension ( ) as a function of solution composition and total surfactant concentration enabled us to determine critical micelle concentration (cmc), minimum surface tension at cmc ( cmc), maximum surface excess concentration ( max), the minimum area per molecule at the aqueous solution/air interface (Amin), and the effectiveness of surface tension reduction ( cmc). The thermodynamic parameters of micellization ( G mic, H mic, and S mic) for these mixtures were also calculated. Temperature and polymer effects on micellization, adsorption and effectiveness of surface reduction are discussed in term of these parameters.