Solution Properties of a Saponin (Acaciaside) in the Presence of Triton X-100 and Igepal

Abstract

The micellization of the saponin, Acaciaside, and its mixed-micelle formation with Triton X-100 were studied by fluorimetric and microcalorimetric methods. The energetics of the micellization process and the polarity of the mixed micelles formed were evaluated. The nonideality of the mixed micelles (the deviation from Clint's equation) and the molecular interactions of Acaciaside with Triton X-100 in the mixed micelles were quantified by Rubingh's formalism in light of regular solution theory. The Acaciaside was found to protect both Triton X-100 and Igepal from clouding. Using the clouding point as the solubility limit of the surfactant (here Triton X-100 and Igepal) the energetics of the process have also been evaluated. Similar to hydrophobic solutes, the entropies of solution of both Triton X-100 and Igepal are significantly negative.

Micellar size and phase behavior in n-octyl-β-d-thioglucoside/Triton X-100 mixtures: The effect of NaCl addition

“…The fact that the calculated H 0 CP values are negative indicates that the net balance is exothermic, thus suggesting that association of the dehydrated micelles is the dominant factor. It should be noted that the exothermicity of the clouding process in TX100-based systems, which was attributed to the aggregation of weakly solvated amphiphile molecules and their passing into a condensed phase, has been observed previously [38][39][40]. Our data indicate that this mechanism becomes more relevant as the NaCl concentration increases.…”

“…Thus, according to the phase-separation model, the cloud point can be considered to be the solubility limit of the surfactant when the phase separation occurs [21,27,38,39]. As a result, the standard Gibbs energy of solubilization, G 0 CP , can be determined using the following equation:…”

Energetics of clouding and size effects in non-ionic surfactant mixtures: The influence of alkyl chain length and NaCl addition

“…As the clouding species above the cloud point release their solvated water and separate out from the solution, the cloud point can be considered as the limit of its solubility [4,[37][38][39][40]. Hence, the standard Gibbs free energy of solubilization, DG 0 CP , can be determined using the following equation:…”

Interfacial and wetting behavior of natural–synthetic mixed surfactant systems

“…In the case of surfactant formulation, apart from good wetting and surface activity, biodegradability and low ecotoxicity are also extremely important requirements from the environmental view point. The available literature shows that there have been fewer studies on natural surfactants 6,[15][16][17][18][19][20][21][22][23] compared to the enormous number of studies on synthetic surfactants. [1][2][3][4][5][7][8][9][10][11][12][13][14] In practice, also, they are even not able to substitute a small fraction of the worldwide consumption of totally synthetic surfactants.…”