Surface activity and association behavior of nonaoxyethylene n-dodecylether in aquo amino acid medium:: Tensiometry, small-angle neutron scattering, dynamic light scattering and viscosity studies

Solubility, tensiometric, small-angle neutron scattering (SANS), dynamic light scattering (DLS) and viscometric measurements were carried out to elucidate the solution and morphological properties of nonaoxyethylene n-dodecyl ether [CH3(CH2)(11)(OCH2CH2)(9)OH], C12E9 over a limited range of temperature and surfactant concentration, both in the presence and in the absence of amino acids (AAs) The amino acids used were glycine, alanine and valine. Clouding temperatures of C12E9 under various conditions were determined. Surface tension was used to determine the critical micelle concentrations (CMC) of surfactant-amino acid mixtures. It seems that the structure breaking ability of AAs and their possible interaction with surfactant affect the micellization process. Viscosity, SANS, and DLS measurements of the surfactant solutions were done and the aggregation number and hydrodynamic radii were computed at three different temperatures of 30, 45 and 60 degrees C. Among the AAs investigated, the effect of alanine was found to be different from the other amino acids. (c) 2007 Elsevier B.V. All rights reserved.