Mesoporous hybrid and nanocomposite thin films. A sol–gel toolbox to create nanoconfined systems with localized chemical properties

Mesoporous Thin Films (MTF) can be created by combining sol–gel synthesis, template self-assembly and chemical surface modification. A wide palette of inorganic (oxides, phosphates, carbon-based, etc.) and hybrid organic–inorganic frameworks with a variety of composition, pore sizes, and nanoscale, organic or biological functions located in the inorganic skeleton, pore surface or pore interior can be obtained. The properties of the functional pore systems are tuned by the pore size and geometry, wall composition and surface features. These MTF with interesting electronic and optical controlled features are indeed a “nanofacility”. Well-defined monodisperse sized pores also act as nanoreactors, or nanocavities with controlled environment and behaviour. In the last years, the production of accessible MTF, in which either the pore surface or pore volume can be modified by organic functional groups or nanoparticles has been thoroughly explored. Each highly controlled MTF originated from a reproducible and modular synthesis is in itself a building block for more complex structures, presenting order at different length scales (molecular, mesoscopic, macroscopic), and novel properties derived thereof. Selected examples of optical and chemical behaviour of these multiscale materials are presented to illustrate these points.