High Internal Phase Emulsions Stabilized by a Zeolite–Surfactant Combination in a Composition-Dependent Manner

• DOI: 10.1021/acs.langmuir.9b03053
• Publication Date: 2019-12-10T02:37:31Z
• Authors: Alban Gossard; Nicolas Fabrègue; Audrey Hertz; Agnès Grandjean
• Keywords: Zeta potential; Dodecane; Phase inversion

As a step toward synthesizing zeolite-based porous materials, this study demonstrates for the first time feasibility of stabilizing oil-in-water (O/W) high internal phase emulsions (HIPEs) using cationic surfactant (tetradecyltrimethylammonium bromide, TTAB) and "homemade" submicronic Linde type A zeolite particles. The particles are hydrophilic therefore do not attach to dodecane-water interfaces, but surface tension measurements electrochemical data show that their can be activated by electrostatic subsequent hydrophobic adsorption TTAB. Comparing isotherm TTAB zeta potential with droplet sizes rheological properties emulsion shows stabilization mechanism depends on TTAB/zeolite weight ratio. At low ratios (≤0.2 wt %), gel-like O/W Pickering HIPEs form, at intermediate concentrations, become more hydrophobic, leading inversion W/O emulsions. (>1.25 second occurs creamy form through different mechanism. In case indeed, fully covered bilayer remain dispersed in aqueous no interface. is stabilized repulsion between highly positively charged adsorbed