A pre-modification-direct synthesis route for the covalent incorporation and monomeric dispersion of hydrophobic organic chromophores in mesoporous silica films

Mesoporous silica films covalently doped with hydrophobic disperse red chromophores have been prepared with a new pre-modification-direct synthesis route via a dip-coating technique using P123 surfactant as the structure-directing agent under acidic conditions. The disperse red chromophores were pre-modified with hydrophilic alkoxylsilanes and then hydrolyzed and co-condensed with tetraethylorthosilicate to form mesostructured hybrid films. The effect of aging time of starting sols and chromophore concentrations on the mesostructures and dye aggregations were investigated. Non-mesostructured films were also prepared as a reference. In the mesostructured hybrid films, the hydrophilic silane groups of the modified disperse red were covalently linked onto the pore surface while the hydrophobic disperse red chromophores monomerically dispersed in the pore spaces of the films rather than restricted within the silica walls due to its hydrophobic nature.