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The Effect of Methanol on the Micellar Properties of Dodecyltrimethylammonium Bromide (DTAB) in Aqueous Medium at Different Temperatures
Author(s) -
Shah Sujit Kumar,
Chatterjee Sujeet Kumar,
Bhattarai Ajaya
Publication year - 2016
Publication title -
journal of surfactants and detergents
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.349
H-Index - 48
eISSN - 1558-9293
pISSN - 1097-3958
DOI - 10.1007/s11743-015-1755-x
Subject(s) - chemistry , gibbs free energy , critical micelle concentration , surface tension , gibbs isotherm , enthalpy , thermodynamics of micellization , aqueous solution , methanol , thermodynamics , micelle , pulmonary surfactant , adsorption , solvophobic , organic chemistry , molecule , biochemistry , physics
The micellar properties of dodecyltrimethylammonium bromide (DTAB) in water and methanol water mixtures at different temperatures have been studied by conductivity and surface tension measurements. The critical micelle concentrations (CMC), degree of ionization (α), standard Gibbs free energy of micellization ( Δ G m o ), standard enthalpy of micellization ( Δ H m o ), standard entropy of micellization ( Δ S m o ) and free energy of transfer ( Δ G trans o ) were evaluated from conductivity data. The CMC, maximum excess surface concentration ( Γ max ), area occupied per surfactant molecule ( A min ), surface pressure at the CMC ( π cmc ), packing parameter ( P ) and standard free energy interfacial adsorption ( Δ G ads o ) were estimated from surface tension measurements. The CMC of DTAB was found to increase with increasing volume fraction of methanol and increasing temperature. Thermodynamic parameters and surface properties revealed that the addition of methanol changes the relevant physicochemical properties which affect the process of micellization.