The influence of surfactants on the stability of cyclodextrin (CD) Pickering emulsions is not well understood. In this study, we report two-way effects of Tween 80 and soybean lecithin (PL) on the long term stability of Pickering emulsions stabilized by the self-assembled microcrystals of α-CD and medium chain triglycerides (MCT). The CD emulsions in the absence and presence of Tween 80 or PL at different concentrations were prepared and characterized by the droplet size, viscosity, contact angle, interfacial tension and residual emulsion values. After adding Tween 80 and PL, similar effects on the size distribution and contact angle were observed. However, changes of viscosity and interfacial tension were significantly different and two-way effects on the stability were found: (i) synergistic enhancement by Tween 80; (ii) inhibition at low and enhancement at high concentrations by PL. The stability enhancement of Tween 80 was due to the interfacial tension decrease caused by the interaction of Tween 80 with CD at the o/w interface at lower concentrations, and significant viscosity increase caused by the Tween 80-CD assembly in the continuous phase. For PL at low concentrations, the replacement of α-CD/MCT by α-CD/PL particles at the o/w interface was observed, leading to inhibitory effects. High concentrations of PL resulted in an extremely low interfacial tension and stable emulsion. In conclusion, the extensive inclusion of surfactants by CD leads to their unique effects on the stability of CD emulsions, for which the changes of viscosity and interfacial tension caused by host-guest interactions play important roles.

Nanocrystalline Ag doped silica inverse opals were prepared by a sol-gel chemistry method via templating of polystyrene colloidal crystals. The ordered structures of colloidal crystal templates and inverse opals are characterized by scanning electron microscopy. Ag nanocrystals size is estimated as 20~30nm by Scherrer Formula from X-ray diffraction. The color and the stop band of the inverse opals are characterized by transmission spectrum. And five emission peaks of the nanocrystalline silver clusters are observed from fluorescence spectrum.

Foaming and gelation of slurry is a recently invented processing route for fabricating porous ceramic. According to the method, a mechanical stir process was introduced to the ceramic slurry added with surfactant, then initiator was added to induce fast gelation between organic monomers and ceramic powder, the green body was obtained after a subsequently drying process. At last, porous ceramic was fabricated after sintering the green body at high temperature. Effects of surfactant volume content and several stirring factors on porosity are studied in this paper. It results that there is a proportional relationship between porosity and Reynolds number which only changes when stir time varies, different slurry or surfactant volume content results in similar relationship between porosity and Reynolds number.

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Stir-froth-polymerization is a novel technique for producing highly porous ceramics, in which bubbles are formed by a mechanical frothing in aqueous slurry of ceramic powders. Many work had be done about the porosity, the permeability and the mechanical strength of the porous ceramics derived from this method, but there are still a lot of things remain unclear. This paper focuses on the mechanism of frothing, and the influence of parameters in the mechanical frothing. It was found that the stir time, the stir speed and the viscosity of the slurry have influence on the average cell-size and the distribution of them respectively. The average cell-size can be controlled in the range from 60 to 160 μm by adjusting the parameters.

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