title: Physicochemical studies on cetylammonium bromide and its modified (mono-, di-, and trihydroxyethylated) head group analogues. Their micellization characteristics in water and thermodynamic and structural aspects of water-in-oil microemulsions formed with them along with n-hexanol and isooctane.
abstract: The micellization behavior of cetylammonium bromide and its mono-, di-, and trihydroxyethylated head group analogues and water/oil (w/o) microemulsion formation with them have been studied with detailed thermodynamic and structural considerations. The critical micellar concentration, micellar aggregation number, and behavior of the surfactants at the air/solution interface have been studied in detail. The results have been analyzed and discussed. The formation of the w/o microemulsion stabilized by the aforesaid surfactants in conjunction with the cosurfactant n-hexanol in isooctane has been investigated by the dilution method. The energetics of the transfer of cosurfactant from oil to the interface has been estimated. The structural parameters, namely, droplet dimension, droplet number, and population of surfactant and cosurfactant on the droplet surface, have also been estimated. The efficacy of the surfactants in respect to water dispersion in oil and cosurfactant concentration level at the oil/water interface has been worked out. Such microemulsions are prospective compartmentalized systems to assist enzyme activities. In this respect, the trihydroxyethylated head group analogue in the above series has been found to be a better performer for the preparation and stabilization of microemulsions that has correlated well with its performance than the others in the hydrolysis of p-nitrophenyl-n-hexanoate by the enzyme Chromobacterium viscosum lipase.
authors.affiliation: Centre for Surface Science, Department of Chemistry, Jadavpur University, Kolkata 700 032, India.
authors.forename: Debolina
authors.initials: D
authors.lastname: Mitra
authors.forename: Indranil
authors.initials: I
authors.lastname: Chakraborty
authors.forename: Subhash C
authors.initials: SC
authors.lastname: Bhattacharya
authors.forename: Satya P
authors.initials: SP
authors.lastname: Moulik
authors.forename: Sangita
authors.initials: S
authors.lastname: Roy
authors.forename: Debapratim
authors.initials: D
authors.lastname: Das
authors.forename: Prasanta K
authors.initials: PK
authors.lastname: Das
mesh_terms: D004655:Emulsions; D000441:Hexanols / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D009795:Octanes / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D018629:Spectrometry, Mass, Secondary Ion; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D004655:Emulsions; D000441:Hexanols; D008823:Micelles; D009795:Octanes; D000644:Quaternary Ammonium Compounds; C521669:cetyl ammonium bromide; D014867:Water; C036260:1-hexanol; C045798:2,2,4-trimethylpentane