Physicochemical studies of octadecyl-trimethyl-ammonium bromide: a critical assessment of its solution behavior with reference to formation of micelle, and microemulsion with n-butanol and n-heptane.
Octadecyl-trimethyl-ammonium bromide (C18TAB) is a much less studied representative in the alkyltrimethylammonium halide surfactant series. A comprehensive study of its normal and reverse micelle (microemulsion) formation has been herein conducted by the methods of conductometry, tensiometry, fluorimetry, and microcalorimetry. The energetics of its air/liquid interfacial adsorption and self-association in aqueous solution have been examined. The phase behavior of its combinations with water, n-butanol, and n-heptane in the formation of microemulsions have been investigated with identification of a variety of phases. The energetics of formation of water dispersion in oil (w/o) has been evaluated from dilution experiments conducted at different temperatures. From the results, structural parameters of the droplets have been determined at different [water]/[surfactant] mole ratios (omega) and temperatures. The w/o dispersions have evidenced both volume- and temperature-induced conductance percolation. The results have been treated in light of the Scaling equations, and the associated parameters for the process have been determined. The activation energies for the temperature-induced percolation process of the w/o dispersion have been evaluated and assessed.
Centre for Surface Science, Department of Chemistry, Jadavpur University, Kolkata-700032, India.
Kajari
K
Maiti
Indranil
I
Chakraborty
Subhash C
SC
Bhattacharya
Amiya K
AK
Panda
Satya P
SP
Moulik