Study of the effect of electrolyte and temperature on the critical micelle concentration of dodecyltrimethylammonium bromide in aqueous medium

Conductivity and fluorescence studies on the micellization properties of sodium cholate and sodium deoxycholate in aqueous medium at different temperatures: Effect of selected amino acids

“…Moreover, the reason for the observed decreasing trend of D mic S o values with temperature might be that self-aggregation process becomes poorer at higher temperatures because of enhanced molecular motion [66]. A similar effect of temperature on D mic H o and D mic S o values for ionic surfactants has also been examined in the literature [31,44,67].…”

“…A perusal of figure 5 indicates that X CMC values pass through a broad minimum at temperatures from (298.15 to 308.15) K for both the surfactants. This type of behavior is characteristic of most ionic and several non-ionic surfactants as elicited in literature [31,[45][46][47]. Such a complex effect of temperature on the X CMC values of surfactant in aqueous medium can be analyzed in terms of hydrophobic and hydrophilic hydrations [48].…”

“…Conductivity measurements have been carried out with digital Conductivity Meter Cyberscan CON-510, working on a principle explained elsewhere [31]. The concentration of the aqueous solution of NaC (1 to 20) mmol Á kg À1 and NaDC (0.5 to 10) mmol Á kg À1 was varied by adding small aliquots of concentrated stock solution of these surfactants to the known volume of pure water and 0.1 mol Á kg À1 aqueous solution of amino acids in the double walled vessel by means of a (10 to 100) lL Eppendorf micropipette.…”

“…The reproducibility of conductivity measurements was estimated to be ±15 lS Á cm À1 . The fluorescence probe study of investigated bile salts has been performed with LS-55 Perkins Elmer Fluorescence Spectrophotometer [31]. The excitation wavelength has been kept at 334 nm and the emission has been recorded at (373 and 384) nm.…”

“…The concentration corresponding to these break points has been identified with the critical micelle concentration (CMC) of bile salts and determined as cited in literature [31]. However, it is important to mention that the break points in these plots are not sharp (figure 3), which has been a feature associated with aqueous solutions of bile salts [33,34] and can be attributed to a stepwise micellization process instead of an instantaneous micelle formation process [35].…”