D. Riassetto

Morphology-wettability relations in artificially structured superhydrophilic TiO2–SiO2 composite films

Naturally superhydrophilic TiO2–SiO2 composite films were deposited through a sol–gel route and the morphology of these films was artificially modified by nanosphere lithography using polystyrene spheres. Morphology changes induced by this structuration were studied by optical, scanning electron, and atomic force microscopy. The water wettability of the so-obtained films over aging under ambient atmosphere was then studied with respect to the sol composition and morphological features. This study i/confirms the assumption of a natural superhydrophilicity of composite films intrinsically induced by TiO2–SiO2 granular interfaces and ii/shows that this property can be greatly improved by artificially induced morphology features. Such features are discussed on the basis of well-established surface thermodynamic models.

Synthesis and functionalities of noble metal nanoparticles formed through simple all-inorganic photochemical procedures

The photochemical reduction of metal precursors under UV light has been studied to produce noble metal nanoparticles. Depending on the metal (Pt, Au or Ag) and precursor (chlorinated or nitrate) natures, different 1-step or 2-step photolytic or photocatalytic reduction mechanisms have been investigated. These mechanisms yield simple all-inorganic methods to generate metal nanoparticles in liquid medium and disperse these particles at the surface of various kinds of supports. Depending on the metal particle and support natures, different functionalities can arise from such easy and low-cost photometallisation methods.