Concentrated emulsions have been widely considered as templates for the preparation of macroporous structures. Replacing concentrated emulsions by fine ones should rather lead to materials having large mesopores. However, fine emulsions were barely investigated for this purpose. On the other hand, mesostructured silica SBA-15 can be prepared from Pluronic P123 micelles according to the cooperative templating mechanism. Starting from mixture of fine emulsion and Pluronic P123 micelles, it is expected to obtain silicas with a controlled hierarchical mesoporosity. The fine emulsion has been formulated from the Kolliphor/Myristate/Water system. To get informations concerning the degree of compatibility between the two surfactants, which can affect the formation of the porous materials, the Kolliphor/P123/water system has been investigated in detail. The structural parameters of the mixed liquid crystal phases have been determined and the mixed micellar structure has been investigated by SAXS. The hierarchical porous silicas have been synthetized combining fine emulsion and Pluronic micellar solution. The materials porosity features strongly depend on the weight proportion between the fine emulsion and the P123 micelles. If this proportion is lower than 5/5, mesoporous silicas present a dual mesoporosity. By contrast, by increasing this proportion the mesopore size distribution only shows large mesopores.
Herein, mesostructured silica materials have been prepared through the Cooperative Templating Mechanism (CTM) using kolliphor EL (KEL) as biocompatible surfactant.First, the behavior of KEL in water has been studied and the phase diagram has been determined. KEL forms micelles (L1) in water and in higher concentrations a liquid crystal domain appears, which is constituted of a cubic phase (Pm3n) and a direct hexagonal phase.Small Angle X-ray Scattering (SAXS) experiments were performed to study the structure of the Organized Molecular Systems. We show that KEL leads to spherical micelles in water, which have a radius comprised between 6.2 and 6.5 nm, depending on the surfactant concentration.Then, mesoporous materials were synthesized and characterized by SAXS measurements and nitrogen adsorption-desorption analysis. The structure of the recovered material is affected by the surfactant/silica molar ratio. Indeed, the mesopore ordering is detected only for ratios in the range between 0.017 and 0.031. As long as ordered mesostructures are obtained, the mesopores diameters are in accordance with the dimension of the hydrophobic size of the micelles.
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