Caracterização por Espectroscopia Raman ressonante de cadeias lineares de carbono encapsuladas por nanotubos de carbono de paredes múltiplas

Abstract

The linear carbon chains(carbynes) have been of growing interest in recent years, mainly due to the fantastic properties predicted for this allotropic form of carbon, sp hybridization, which put it as a fascinating material as graphene and carbon nanotubes, sp2 hybridization, and diamond, sp3 hybridization. However, the practical realization of the carbynes has failed for several years in its high instability under ambient conditions, which has been successfully overcome by the confinement of the carbon chains inside carbon nanotubes. In this scenario, the experimental characterization of the hybrid system composed of the linear chains confined in carbon nanotubes becomes a point of fundamental importance, either for the confirmations of theoretical predictions already established, or for the proposition of new theoretical models, that contribute increasingly more so that practical carbyne applications are possible in the near future. In this work, individual samples of multiple wall carbon nanotubes containing linear carbon chains, Cn@MWCNT, in their interior were analyzed by confocal Raman spectroscopy and Tip Enhanced Raman Spectroscopy (TERS), a technique that allows the use of Raman spectroscopy for nanoscale characterizations, in spite of the diffraction limit and low intensity of the Raman signal, and that alowed the identification of new vibrational features related to the Cn@MWCNTs.