Studies on Binary and Ternary Amphiphile Combinations of Tetradecyltrimethylammonium Bromide (C₁₄TAB), Tetradecyltriphenylphosphonium Bromide (C₁₄TPB), and Tetradecylpyridinium Bromide (C₁₄PB). A Critical Analysis of Their Interfacial and Bulk Behaviors

Abstract

Mixed surfactants play a promising role in surface chemical applications. In this study, interfacial and bulk behaviors of binary and ternary combinations of tetradecyltrimethylammonium bromide (C(14)TAB), tetradecyltriphenylphosphonium bromide (C(14)TPB), and tetradecylpyridinium bromide (C(14)PB) have been examined in detail using the methods of tensiometry, conductometry, fluorimetry, and microcalorimetry. The state of micellar aggregation, amphiphile composition in the micelle, extent of counterion binding by the micelle, and interaction among the surfactant monomers in the binary and ternary combinations have been quantitatively assessed in the light of the regular solution theories of Rubingh and that of Rubingh and Holland. The monomer packing in the micelles and their expected shapes have also been estimated from topological considerations. Conceptual rationalization of results has been presented together with associated energetics of the interfacial adsorption and self-aggregation in the bulk.

Amphiphile self-aggregation: An attempt to reconcile the agreement–disagreement between the enthalpies of micellization determined by the van’t Hoff and Calorimetry methods

“…It would be advantageous if both b and n could have been determined from the ITC runs also. We may add here that Majhi et al [36] proposed a computer program for the evaluation of 'n' (on the basis of the mass action model) from ITC runs which has been also used by us on several aggregating amphiphile systems [23]. We have found that the method yields 'n' values fairly lower than that realized by fluorimetry [35].…”

“…It is a dependable physical method to study the process of micellization [42]. There are numerous available literature that have used ITC for amphiphile aggregation [1][2][3][4][5]23,[31][32][33]35,[41][42][43][44][45][46][47], thermodynamics of bilayers-to-micelle transition [48,49], amphiphile interaction with polymers and macromolecules [50][51][52][53][54][55][56][57], characterization of protein solution [58], binding of small molecules with biopolymers [59][60][61], interaction of microemulsion with vesicles [62], determination of second virial coefficient of ionic liquid microemulsion [63], kinetics of reaction [64], etc. We have also used the method and have shown a general way of data treatment for microheterogeneous systems like micelles [65] and microemulsions [66].…”

“…The electrical contribution to the free energy of micellization process essentially originates from the interaction of counterions with micelle. Micellar aggregation number related contribution to the overall free energy change has been shown to be minor [4,23]. [26], complications that may arise due to micellar growth, intermicellar interaction, change in micellar shape, etc.…”

“…We mention that the use of Moroi's Eqs. (10) and (11) on several recently studied amphiphilic systems have indeed shown minor changes in DG m [2,4,23,30]. With this general background, in the subsequent presentation we have dealt with a large number of well studied aggregating aqueous amphiphile systems on which sufficient data are available in literature in a wide span of temperature, and wherein both counterion binding extents and aggregation numbers are mostly available over the same range of temperature.…”

Ternary mixtures of alkyltriphenylphosphonium bromides (C12TPB, C14TPB and C16TPB) in aqueous medium: their interfacial, bulk and fluorescence quenching behaviour

“…29,30 In a recent study, we have elaborately presented properties of the binary and ternary mixtures of tetradecyltrimethylammonium bromide (C 14 TAB), tetradecyltriphenyl phosphonium bromide (C 14 TPB) and tetradecylpyridinium bromide (C 14 PyB). 31 Interesting head group depended results were observed.…”