“Chimie douce” based strategies allow, through the deep knowledge of materials chemistry and processing, the birth of the molecular engineering of nanomaterials. This feature article will highlight some of the main research accomplishments we have performed during the last years. We describe successively the design and properties of: sol–gel derived hybrids, Nano Building Blocks (NBBs) based hybrid materials, nanostructured porous materials proceeds as thin films and ultra-thin films, aerosol processed mesoporous powders and finally hierarchically structured materials. The importance of the control of the hybrid interfaces via the use of modern tools as DOSY NMR, SAXS, WAXS, Ellipsometry that are very useful to evaluate in situ the hybrid interfaces and the self-assembly processes is emphasized. Some examples of the optical, photocatalytic, electrochemical and mechanical properties of the resulting inorganic or hybrid nanomaterials are also presented.

The design, synthesis and some optical properties of hybrid organic-inorganic nanocomposites materials are presented. The properties that can be expected for such materials depend on the chemical nature of their components, but they also depend on the synergy of these components. Thus, the interface in these nanocomposites is of paramount significance and one key point of their synthesis is the control of this interface. These nanocomposites can be obtained by hydrolysis and condensation reactions of organically functionalized alkoxide precursors. Striking examples of hybrids made from modified silicon, tin and transition metal alkoxides are presented. Some optical properties (photochromic, luminescence, NLO) of siloxane based hybrids are also discussed.

The chemical strategies offered by combining sol-gel processes together with the templated growth of inorganic or hybrid networks involving self-assembly with surfactant mesophases or organogels, and with external solicitations allows us, through an intelligent and tuned coding, to develop innovative materials having complex architectures. These methods where chemistry and process are strongly coupled, allow directing the assembling of a large variety of molecular precursors, oligomers, clusters or nanoparticles (nanobuilding blocks) into functional hierarchical structures. In this short review article, the different strategies allowing to design nanostructured and/or microtextured inorganic and hybrid materials shaped as thick or thin films, microparticles and fibres are illustrated with several striking examples developed in our research group.