Effect of Viscosity of cationic surfactants [tetradecyltrimethylammonium bromide (TTAB) and hexadeecyltrimethylammonium bromide (HTAB)] on Critical Micelle Concentration and Various Activation Parameters in (Methanol+ Water) and (Methanol+ Toluene) Systems

Chemistry

The viscosity (η) of cationic surfactants tetradecyltrimethylammonium bromide (TTAB) and hexadeecyltrimethylammonium bromide (HTAB) have been measured in both (methanol+ water) and (methanol+ Toluene) systems at different temperatures. The CMC values for TTAB in these systems at different temperature have been determined from the viscosity vs. concentration plots. The CMC values so obtained are in complete agreement with those obtained from conductance measurements. The values of molar volume and interaction coefficient have been evaluated from the Vand`s equation .The values of molar volume and interaction coefficient increase with increase in temperature and number of carbon atom in hydrophobic chain of the surfactant. The plots of [log η vs. 1/T] are found to be linear and the values of ∆H* have been calculated from the slopes of the linear plots. The values of ∆H* for methanol+10% toluene systems have been calculated. The values of ∆S* and ∆G* have been also calculated for the same systems from Eyring`s and Gibb`s equation respectively at 400C.Various activation parameters for fluidity of both the surfactants in methanol + water systems were also calculated.

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