Photocatalytic flexible films with hierarchical porosity by self-assembling sol-gel process and photoactivation
Résumé
The photocatalytic process was widely developed these last years for water and air depollution. Applications on organic substrates, like textiles, induce new challenges: (i) protect the support against the photocatalytic reactions, (ii) fix the photocatalyst to avoid its release, (iii) keep the flexibility of the organic substrates, (iv) synthesize a porous film at low temperature to promote the pollutant/photocatalyst interactions without damaging the textile. In this context, we developed hybrid composite coatings which insert commercial TiO2 nanoparticles into a silica matrix, used as binder and protective layer. Thanks to the sol-gel process, we introduced organic groups into the matrix in order to promote the film flexibility. Spontaneous porous films were obtained by the self-assembly of the nanoparticles. A photoactivation step allows to improve the film photoactivity generating microporosity, degrading the organic groups in contact with the photocatalyst.