Ion-specific Effect on Oil-in-water Emulsion Gels Containing a Stimuli-responsive Fibrous Assembly of Amidoamine-derivative Hydrogelator.

Amidoamine derivative C18AA forms a highly viscous oil-in-water (O/W) emulsion, called an "emulsion gel." Previously, it was showed that the viscosity sensitively changes with the C18AA concentration, temperature, pH changes, and salt addition. In this work, C18AA concentration in the continuous aqueous phase ([C18AA]w) was investigated at different compositions, and it was found that a threshold concentration value of 16.5 wt% was required to obtain a highly viscous emulsion gel below 45°C. C18AA formed micellar networks in the aqueous phase, and stimuli or additives increase the value of [C18AA]w, so that the C18AA micellar network could grow in the continuous aqueous phase.