Search

We report on the synergic effect of surfactants and chelating agents on the mechanism to remove stubborn keratin grime (keratin-Ca), which is bound with calcium ions and one of the most difficult grimes to remove, in order to make it easier to clean bathtubs in less time and with less scrubbing. Our approach was to focus on keratin swelling, which we achieved by applying aqueous solutions with chelating agents and anionic surfactants, the combination of which greatly improved the swelling ratio, resulting in quick, easy removal of keratin-Ca with water rinsing and little scrubbing. For the swelling process, we added chelating agents and anionic surfactants to swell the keratin-Ca by both capturing calcium ions and improving solution permeation. Furthermore, we measured the structural change of the keratin-Ca during swelling by TD-NMR and confirmed that a certain combination of chelating agent and anionic surfactant improved swelling by affecting not only the amorphous part such as the keratin matrix, but also the crystalline part such as the intermediate filaments (IFs). [ABSTRACT FROM AUTHOR]

Producing structural viscosity in colloidal dispersions, such as vesicles and capsules, prevents separation of dispersed particles by increasing the viscosity between them, which is advantageous in terms of usability. So far, the separation behavior of various particles has been studied; however, there are very few examples wherein a stable dispersion state was constructed and controlled. In this study, we produced stable dispersions induced by the depletion effect in mixtures of vesicles of cationic surfactant derived from triethanolamine-based esterquat (TEQ) and a specific dextrin derivative (SDD) as a non-adsorptive polymer. In the composition region, where 8 to 16% of TEQ vesicles and 1.2% or less of SDDs were mixed, the viscosity increased proportionally with the particle concentration, and it was observed that stable dispersions were produced by structural viscosity. Furthermore, the effects of TEQ and SDD concentrations, and SDD size on the structural viscosity and cohesive energy were investigated, which were similar to the depletion effect in the Asakura-Oosawa (AO) theory. From the results, it was suggested that the structural viscosity of the mixed dispersions (TEQ vesicles and SDDs) was produced by the aggregated TEQ vesicle networks induced by the depletion flocculation. [ABSTRACT FROM AUTHOR]