Understanding Crystalline Materials Using Raman Spectroscopy – Some Examples

In this chapter Raman spectroscopy is used to understand graphene, carbon nanotubes and graphite crystals incorporated in polymers. The samples were prepared by incorporating nanocrystals of graphene into polyethylene and chitosan. Raman spectroscopy studies of graphene incorporated into polyethylene showed that the crystallinity of polyethylene was affected by the presence of graphene in it. It was also observed that the crystallinity of graphene was affected as the concentration of graphene increased. The defects were observed to increase with increasing concentration of graphene. The defect induced in the graphene resulted in change in the magnetic behaviour of graphene. Graphene is diamagnetic and increasing the concentration to 10% resulted in ferromagnetic bahavior. In another study, the Raman spectroscopy studies of CNT and maghemite incorporated into chitosan films was studied. Results showed that the inclusion of maghemite increased the defects in the CNTs. In yet another study involving Raman spectroscopy for chitosan polymers incorporated with graphite and maghemite, it was observed that the defects in graphite increased due to the presence of maghemite. The above studies show that Raman spectroscopy can help us better understand the microstructural modifications in the nanocomposites.