Thermodynamic studies of octyltrimethylammonium chloride in water

Abstract

Densities, heat capacities, enthalpies of dilution at 298 K and osmotic coefficients at 310 K of octyltrimethylammonium chloride were measured as functions of concentration. From the experimental data, the partial molar volumes, heat capacities, relative enthalpies, nonideal free energies and entropies at 298 K were derived as functions of concentration. A comparison between the above data and those of dodecyltrimethylammonium chloride reported in the literature shows that the increase of the alkyl chain length shifts the apparent molar volume vs. concentration curves towards greater values and the heat capacity, relative enthalpy and free energy vs. concentration curves towards smaller values. By assuming the pseudo-phase transition model the properties of micellization (AYm) were graphically evaluated. The AYm values of OTAC compared with those of DTAC are consistent with the increase of the hydrophobicity by increasing the alkyl chain length.

Adsorption of a quaternary ammonium surfactant on Au(1 0 0)

“…This is roughly twenty times larger than the cmc reported for decyltrimethylammonium triflate (DeTMATf) in 0.1 M NaF [13]. The larger cmc for the shorter chained surfactant is congruent with reported cmc values for different length alkyltrimethlyammonium chloride surfactants [31] and sulfobetaines [32].…”

Differential capacity and chronocoulometry studies of a quaternary ammonium surfactant adsorbed on Au(111)

“…This is roughly 20 times larger than the cmc for decyltrimethylammonium triflate (DeTMATf) in 0.1 M NaF which was reported by Brosseau et al . The larger cmc for the shorter chained surfactant is congruent with reported cmc values for different length alkyltrimethlyammonium chloride and sulfobetaine surfactants. The Gibbs excess for OTATf adsorption at the air/liquid interface can be obtained by differentiation of the isotherm and is presented in Fig.…”

Insight into the Hydration of Cationic Surfactants: A Thermodynamic and Dielectric Study of Functionalized Quaternary Ammonium Chlorides

“…The aforementioned studies were carried out using quaternary ammonium salts with a long alkyl chain. This class of cationic surfactants is probably the most studied model for investigating the effects of alkyl chain length and counterions on micellar properties. − However, little is known about quaternary ammonium salts carrying a functional group in addition to the long alkyl chain on the quaternary ammonium. Such substitution should significantly affect headgroup hydration and counterion binding and thus allow the tuning of micelle properties.…”