Superior thermal stability gel emulsion produced by low concentration Gemini surfactant

We report in this work the microstructure, rheological behavior and thermal stability about the gel emulsions formed in water, oil and Gemini surfactant sodium didecamino cystine (SDDC) systems. Optical microscopy results indicate that the oil droplets are polydisperse and closely packed in the gel emulsions. Dynamic rheological measurements reveal that these gel emulsions exhibit typical viscoelastic character of gel-like structure and the viscoelasticity increase along with raising the SDDC concentration. Further analysis by using the cooperation theory of flow demonstrates that the gel emulsion with stronger cohesive interactions and lower number of interaction units are obtained by increasing the SDDC concentration, which enhance the emulsion stability in slowing down emulsion creaming and coalescence. It has been found that the gel emulsion produced by Gemini surfactant SDDC is shown a superior thermal stability upon heating at 50 °C compared with the gel emulsion produced by the monomeric surfactant sodium laurate (SL).