Abstract : This thesis presents the study of oxides (ZnO and SiO2) synthesized by sol-gel method. Firstly, we study the kinectics growth of ZnO nanoparticles in aqueous medium. The aqueous chemical growth of ZnO was done at the ESRF (ID10 beamline) for using the synchrotron radiation (22 Kev). The in-situ monitoring by synchrotron radiation on a substrate placed in solution made up from zinc nitrate hexahydrate [Zn(NO3)2,6H2O, 98%, Acros Organics] and hexamethylenetetramine (HMT, C6H12N4, 99%, Acros Organics) precursors dissolved in equimolar concentration in deionized water (MilliQ, 18.2Mo), allowed us to highlight the presence of ZnO nanoparticles in solution and permit to follow the kinetics of the formation of zinc oxide. In the second part, we have synthesized and analysed mesoporous silica thin films templated by a non-ionic surfactant, the Brij58. This work required to establish the binary phase diagramm Water/Brij58 by Small Angle X-rays Scattering (SAXS) at room temperature. The SAXS study is complemented by the determination of the liquid-solid transition of binary system Water/Brij58 by rheolgy. The study of well structured films was carried out by Grazing Incidence Small Angle X-rays Scattering (GISAXS) and by X-rays reflectivity. Lastly, our aim was then to combine the synthesis of porous thin film with the inclusion of zinc oxide nanocrystals in the pores. We completed this work by using these films as porous host matrix for two fluids, water and CO2.