Infrared (IR) spectroscopy, the study of the interaction of infrared light with matter, is one of the most important techniques available for materials analysis. This chapter, will provide an overview of the principles of IR and Fourier transform infrared (FTIR) spectroscopy and sample preparation. FTIR spectroscopy has been extensively used in both qualitative and quantitative analysis of nanofillers and their nanocomposites. In qualitative analyses, the nanofillers such as metal oxide nanoparticles, carbonaceous nanostructure, clay, nanofiller synergy, and their polymer nanocomposites will be characterized by FTIR spectroscopy. In quantitative analyses, FTIR will be employed to show the influence of a nanofiller on the properties of nanocomposite films through changes in the band intensity of FTIR spectra. The effects of the nanofillers on the phase transformation of nanocomposite films will also be discussed.
