Transport of a model diffusion probe in polyelectrolyte-surfactant hydrogels

In this study, two types of hydrogels were prepared: 1) based on hyaluronan and cationic surfactant septonex (carbethoxypendecinium bromide) and 2) based on diethylaminoethyl dextran and sodium dodecylsulphate. Nile red as a dye diffusion probe was incorporated into hydrogel in their preparation and then its release into surfactant solution and physiological saline was monitored. The release of NR from hydrogels was characterized by the effective diffusion coefficients of NR and structural parameters of hydrogels. The diffusion of NR in hydrogels was dependent on the molecular weight of polyelectrolyte and the ratio between charges of polyelectrolyte and surfactant. In the case of lower ratios, a bigger part of NR was probably incorporated in “pearl necklace structure” which suppressed its mobility. The increase of concentration of surfactant was connected with higher content of NR in free micelles or micelle-like aggregates and the increase in the release of NR. The formation of bigger micelles based on NR and SDS (in comparison with micelles based on NR and septonex surfactant) resulted in their lower diffusivity.Graphical abstract
Source: Colloids and Surfaces A: Physicochemical and Engineering Aspects - Category: Chemistry Source Type: research