Résumé
Mesoporous organosilica nanoparticles (MO-Nps) are classically formed by grafting method and by co-condensation of organosilanes with TEOS. The hydrolysis of organo-bridged silanes gives TEOS-free hybrids called Bridged silsesquioxanes (BS). Using the soft template route, hybrid silica called PMO (Periodic Mesoporous Organosilica) with interesting high organic content are formed and PMO-Nps with hierarchical structures can be designed1. Recently mesoporous hybrid silica Nps with variable structures have been reported (Core/shell and Yolk/shell, etc)2 and PMO-Nps turned out to be a promising platform for nanothermometry applications. We are interested in controlling the relation between the structure and physical and chemical properties of such multifunctional nanoplatforms after encapsulation for further biological applications. Our work is focused firstly on the synthesis of Hollow PMO Nps (HPMO-NPs) with a controlled core cavity and a PMO shell. To engineer these porosities, we used subsequently two templating routes: (1) silica spheres as hard template to form the core cavity and (2) CTAB as soft template and BTEB (1,4-Bis-triethoxysilylbenzene) to achieve the mesoporous PMO shell (Figure). Na2CO3 and HCl are used to successively deliver the two kinds of porosity. Core silica with fixed diameters allow to control both HPMO-NPs sizes and core cavity hollow diameter. We will present the results of a multiscale study of the relation between the structure and the physical properties of HPMO-NPs from structural and optical investigations. Nanothermometry properties of such systems after encapsulation of up-converting nanoparticles will be finally introduced.