Fluorescence probes the early formation of network at the interface of epoxy-silica nanocomposite during curing

The effect of surface modified silica on the cure behavior at the interface of epoxy-silica nanocomposites has been analyzed monitoring the fluorescence of the dansyl probe located at different distances from the silica surface by means of molecular tethers. FTIR analysis revealed the catalytic role of the surface hydroxyls, which is modulated by the surface modification. Fluorescence results show that network formation and associated phenomena as gelation and vitrification occurs first at the interface. The exchange of branched species throughout the permeable interface spreads its influence to the whole system until vitrification is reached. (C) 2014 Elsevier B.V. All rights reserved.