On the use of Raman and FTIR spectroscopy for the analysis of silica-based nanofillers

This paper details our research into the interfacial regions of nanocomposites, using vibrational spectroscopy to characterize the surface chemistry of differently modified particulate fillers. Results obtained from both nano- and micro-silica are reported as a function of silane treatment. Materials with varying surface concentrations of epoxide groups were produced by altering the chemical processing conditions. Raman spectroscopy is capable of providing qualitative data concerning the functionalization level, but the technique is incapable of providing absolute concentrations. Although FTIR should be capable of providing more quantitative data, anomalously high apparent concentrations are obtained, suggesting that the interactions occurring within dispersed particulate systems are rather more complex than implied by classical Beer Lambert behavior.