Properties of poloxamer 407 and polysorbate mixed micelles: Influence of polysorbate hydrophobic chain

In the present study, binary mixed micelles of poloxamer 407 and a homologous series of polysorbate surfactants (polysorbate 20, polysorbate 60, polysorbate 80, polysorbate 85) were investigated. Rubingh's model was applied to determine the physicochemical parameters of the poloxamer/polysorbate binary systems. The obtained negative values of the interaction parameter and excess Gibbs energy showed the existence of synergism. By comparing the values of the investigated parameters, and the values of micropolarity measurements, it was noticed that the inclusion of polysorbate surfactants with longer and more saturated hydrophobic chains leads to improved packing in the micellar interior and stronger interactions. (C) 2016 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.