Micellization and Related Behaviors of N-Cetyl-N-ethanolyl-N,N-dimethyl and N-Cetyl-N,N-diethanolyl-N-methyl Ammonium Bromide

Abstract

The micellization characteristics of N-cetyl-N-ethanolyl-N,N-dimethyl and N-cetyl-N,N-diethanolyl-N-methyl ammonium bromides have been investigated by microcalorimetric, conductometric, and fluorimetric techniques. The critical micellar concentration (cmc), counterion binding of micelles, their aggregation number, and thermodynamics of micellization have been evaluated at eight different temperatures in the range of 288-323 K. The Gibbs free energy, enthalpy, entropy, and specific heat of the micellization process have been evaluated by the direct calorimetric method as well as by the indirect method of van't Hoff by processing the cmc results of microcalorimetry and conductometry at different temperatures. The differences of the results obtained by these two procedures have been discussed. The thermodynamic results have been compared with values for the parent compound, N-cetyl-N,N,Ntrimethylammonium bromide, and the effect of the substitution of the ethanolyl group in place of the methyl group on the surfactant head has been rationalized. The effects of the salt NaBr on the thermodynamics of micellization of the studied surfactants have been also studied from the microcalorimetric measurements.

What can isothermal titration microcalorimetry experiments tell us about the self‐organization of surfactants into micelles?

“…As a result, the aggregation process is thermodynamically favored and becomes spontaneous at higher temperatures. This was observed in the case of many surfactants such as pluronic F127 , Tetronic 304 (Roques et al, 2009), N-cetyl-N,N-diethanolyl-N-methyl ammonium bromide (CDMAB) (Chatterjee et al, 2002). However, in some cases, the variation of the temperature of the experiment does not affect DG mic (Hildebrand et al, 2004).…”

Physicochemistry of hexadecylammonium bromide and its methyl and ethanolic head group analogues in buffered aqueous and gelatin solution

“…The water used in the study was doubly distilled water of specific conductance 2-4 μS cm -1 at 303 K. The surfactants produced expected cmcs as reported in literature. 49,51 They did not contain surface active impurities as γ (surface tension) vs. log[surfactant] plots did not produce minima.…”

“…The preparation and characterization of the other surfactants used were reported elsewhere. 7,8,18,49,51 They are subdivided in two groups as presented in scheme 1. Borax and boric acid were AR grade products of Merck (India).…”

Physicochemical Studies on the Interfacial and Bulk Behaviors of Sodium N‐Dodecanoyl Sarcosinate (SDDS)

“…The salt effect on the CMC studied herein (discussed later) has lent support to the above. A literature survey supports that ionic surfactants like sodium dodecyl sulfate (SDS), cetyl pyridinium chloride (CPC), sodium dioctyl sulfosuccinate, cetyl ethyl dimethyl ammonium bromide (CEDAB), cetyl diethanolyl methyl ammonium bromide, tetradecyl triphenyl phosphonium bromide etc… show mild minima in their CMC versus temperature profile [17][18][19]. However, N-methyl-Ndecanoyl glucamide (MDGA) [19], a non-ionic alkylpolyglucoside and an octyl glycoside [20,21] also have minima in the CMC-temperature plot; ethoxylated tertoctylphenol [22] another non-ionic surfactant, has shown a decreasing trend in CMC with increasing temperature in the studied temperature range 288-313 K. The above account tells that the effect of temperature on CMC is system dependent.…”