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Mixed Micellization Behavior of m ‐2‐ m Gemini Surfactants with Some Conventional Surfactants at Different Temperatures
Author(s) -
Sood Ashwani K.,
Singh Kultar,
Kaur Jasbir,
Banipal Tarlok S.
Publication year - 2012
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/s11743-011-1314-z
Subject(s) - chemistry , aqueous solution , micelle , ammonium bromide , pulmonary surfactant , ammonium chloride , bromide , thermodynamics of micellization , cationic polymerization , polyethylene glycol , aggregation number , inorganic chemistry , critical micelle concentration , polymer chemistry , organic chemistry , biochemistry
Mixed micellization behavior of dimeric cationic surfactants ethanediyl‐1,2‐bis(dimethyl alkyl ammonium bromide) ( m ‐2‐ m where m = 10, 12) with conventional single chain cationic surfactants like cetyltrimethyl ammonium bromide (CTAB), cetylpyridinium chloride (CPC), tetradecyl dimethyl benzyl ammonium chloride (C14BCl) and cetyl dimethyl benzyl ammonium chloride (C16BCl) were studied in aqueous and aqueous polyethylene glycol (PEG) solutions at 298.15, 308.15 and 318.15 K respectively using conductometric and viscometric methods. In aqueous solutions, all the combinations (except 12‐2‐12 + CTAB) were found to behave nonideally with mutual synergism which decreases with increase in temperature. Various thermodynamic parameters of micellization like Δ G m o , Δ H m oand Δ S m owere evaluated and discussed. Similarly in presence of PEG, the thermodynamic properties like Δ G t o , Δ H t oand Δ S t oassociated with the transfer of surfactant monomers from the medium consisting of polymer‐free mixed micelles to polymer‐bound mixed micelles at various temperatures were also calculated. The negative values of Δ H t oshow that aggregation process is more exothermic than micellization whereas the negative values of Δ S t oindicate that the presence of polymer bound mixed micelles decreases the degree of randomness of the system. Viscosity studies show that in aqueous solutions all the combinations of 10‐2‐10/12‐2‐12 display negative departure in the relative viscosity (η r ) from additivity rule which decreases with increase in temperature. Similarly in the presence of 5% PEG solutions the magnitude of the negative departure decreases for all the combinations and becomes positive in the case of C14BCl and CPC combinations with the studied gemini surfactants at higher temperatures.