Interaction between Cetyltrimetylammonium Tosylate and Two Poly(oxyethylene)-Poly(oxypropylene)-Poly(oxyethylene) Block Copolymers Studied by Cyclic Voltammetry

EDUARDO N. SCHULZ; RUBÉN E. AMBRUSI; SILVANA G. GARCÍA; MAXIMILIANO BRIGANTE

Journal of Chemical & Engineering Data

America Chemical Society

Año: 2012 p. 2956 - 2962

Mixtures of hexadecyltrimetylammonium tosylate (hexadecyltrimethylammoniump-toluene sulfonate or cetyltrimethylammonium tosylate, CTAT) with twoPluronic block copolymers, F127 and F68, were studied using cyclic voltammetry. Thehydrodynamic radii of aggregates were analyzed in light of the aggregate composition. Itwas confirmed that the mixtures CTAT-F127 and CTAT-F68 have different behaviors.This corroborates that the interaction between different Pluronics and the sameconventional surfactant depends on the kind of copolymer surfactant and also thatdifferences in the size of the hydrophobic and the hydrophilic parts of the molecule maycause different behaviors. The penetration of CTAT into the micelle core may be moreor less hindered by the size and structure of the hydrophilic shell. However, once theconventional surfactant has penetrated the corona and reached the polyoxypropylene core in a cooperative manner, theaggregates tend to disappear, thus being replaced by smaller structures, which are probably complexes having a finite number ofCTAT molecules per copolymer molecule.