Comparative studies between monomeric and polymeric sodium 10-undecenoate micelles

Abstract

When aqueous solutions of sodium 10-undecenoate at concentrations above the cmc of the surfactant (8.24 g/dm3; 0.04 M) are irradiated by y rays the low molecular weight polysoap poly (sodium 10-undecenoate) is formed which has a degree of polymerization equal to ten and exhibits micellar behavior by solubilizing hydrophobic molecules. The cmc of the polymeric micelle is equal to zero, each micelle being built of a single poly(sodium 10-undecenoate) molecule. These micelles, called "intramolecular" micelles, are known to have equal hydrated size with the corresponding monomeric micelles of sodium 10-undecenoate. Fluorescence studies with the micropolarity probe pyrene show that the fluorophore penetrates the intramolecular polymeric micelle less than the monomeric one. This is understood in terms of the more compact structure of the polymeric micelle due to the presence of polymerization-induced covalent bonds among the terminal methylene groups of the undecenoate chains. When the concentration of poly(sodium 10-undecenoate) in water exceeds 2.06 g/dm3 hydrophobic aggregation of intramolecular micelles occurs which leads to the formation of large "intermolecular" micelles having an intrinsic viscosity of 0.079 100 mL/g compared to 0.048 100 mL/g for the intramolecular and monomeric micelles.

Novel pseudostationary phase for micellar electrokinetic capillary chromatography

“…Others have confirmed these results [ 1,17,18]. Organic molecules are solubilized by the oligomer in a similar fashion to micelles of the free surfactant, although in a more rigid and more polar state [17,19].…”

Interactions between Surfactants and Particles: Dispersion, Surface Modification, and Adsolubilization

“…Polymerization of sodium 10-undecenoate micellar solutions either by irradiation or by free radical initiators has been shown to yield low-molecular-weight oligomers (17)(18)(19). Fixation of bilayers onto alumina particles using polymerizable surfactants such as sodium 10-undecenoate and sodium 10-undecenyl sulfate has been performed (20)(21)(22).…”

Reactive Surfactants

“…It is a basic principle that the surface-active properties of any kind of reactive surfactant will be changed during polymerization [19][20][21][22]. Therefore, it could be possible that during heterophase polymerizations with reactive surfactants stability problems occur and a higher amount of coagulum is produced compared with non-reactive surfactants.…”