Explanation of experimental results of mixed micelles of homologous surfactants through a MM2 bidimensional modeling.
A computational modeling (in gas phase) to study the disposition of the homologous surfactants in a bidimensional simple model of mixed and homogeneous micelles was performed for the case of R-trimethylammonium bromide surfactants with different linear R lengths from R = C(5) to C(17). First, the bidimensional homogeneous (one component) micelle was modeled, and as a second step, heterogeneous (two components) bidimensional micelles were modeled. The difference in the number of carbon atoms between hydrocarbon chains of the surfactants in the heterogeneous micelles, Δn(C), ranged from 2 to 8. Results were contrasted with experimental data obtained at our own laboratory. The exothermic values of the steric energy changes showed strong attraction between components of homologous surfactants mixture, especially when one of the surfactants has a long chain. It may be argued that the inclusion of a shorter surfactant in the mixture and the twisting of the longer surfactant makes the bidimensional arrangement formation more exothermic. All predictions were in agreement with previous experimental results.
Ferreira
María Luján
ML
PLAPIQUI-UNS-CONICET Planta Piloto de Ingeniería Química, Camino la Carrindanga Km 7, CC 717, 8000 Bahía Blanca, Buenos Aires, Argentina.
Sierra
María Belén
MB
Morini
Marcela A
MA
Rodríguez
José Luis
JL
Minardi
Rossana
R
Schulz
Pablo C
PC