Raman spectroscopy has been widely used to identify the physical properties of carbon nanotubes(CNTs),and to assess their functionalization as well as orientation.Recently,Raman spectroscopy has become a powerful tool to characterize the interfacial properties between CNTs and polymer matrices.This review provides an overview of micro-Raman spectroscopy of CNTs and its application in studying CNT reinforced polymer composites.Based on the specific Raman band shifts relating to the mechanical deformation of CNTs,Raman scattering can be used to evaluate the interactions between the CNTs and the surrounding polymer in the composites,and to detect the phase transitions of the polymer,and investigate the local stress state as well as the Young's modulus of the CNTs.Moreover,we also review the current progress of Raman spectroscopy in various CNT macroarchitectures(such as films,fibers as well as composite fibers).The microscale structural deformation of CNT macroarchitectures and strain transfer factors from macroscale architectures to microscale structures are inferred.Based on an in situ Raman-tensile test,we further predict the Young's modulus of the CNT macroarchitectures and reveal the dominating factors affecting the mechanical performances of the CNT macroarchitectures.
