Résumé
A versatile and eco-compatible preparation route of functional ordered mesoporous materials will be described. It relies on the use of assemblies of hydrophilic diblock copolymers, in place of classical amphiphilic templates, as new structuring and functionalizing agents for the direct synthesis, at room temperature and in water, of polymer-functionalized mesoporous silica.The new structuring agents are dynamic PolyIon electrostatic Complex (PIC) micelles formed between double-hydrophilic-block-copolymers (DHBC) (constituted of a neutral block and an ionizable one) and an oppositely charged homopolyelectrolyte, which can be considered as an auxiliary of micellization of DHBC polymers.The different advantages of using PIC micelles are the following: due to their sensitivity to physicochemical parameters, PIC micelles allowed obtaining various hybrid mesostructures (cubic, 2D-hexagonal, lamellar...) by simply adjusting the material synthesis conditions using a unique DHBC/homopolyelectrolyte system. This is a consequence of the adjustable composition and water content of the polyion complex phase. The micellization process, which can be controlled by pH or ionic strength, is reversible in water and this allowed the recovery and recycling of the porogen polymers.Very interestingly, the use of PIC micelles permitted the direct preparation of polymer-functionalized mesopores. This was possible due to the easy dissociation of the polyion complex within the pores, selectively releasing the auxiliary of micellization while the DHBC remained for functionalizing the pores. This new method ensures an homogeneous functionalization of the mesopores, a control of the functional polymer chain lengths and a sufficient mesoporous volume. Moreover, the properties of the functional chains could be varied (acid, basic, metal-complexing...). Finally, this preparation route was extended to bio-functional hybrid mesophases useful as drug delivery systems [3] The direct formation of drug-loaded polymer-functionalized mesoporous materials was developed by using drug-polymer complex micelles as structuring agents ; this was shown with antibiotics exhibiting a pH-triggered release. Furthermore, studies are currently under way to estimate the catalytic performances of the new functional materials.