Raman and FTIR spectroscopy as valuable tools for the characterization of polymer and carbon nanotube based composites

Abstract

The combination of the unique properties of carbon nanotubes (CNTs) with conjugated polymers makes their combined composite materials interesting as multifunctional systems with great potential. Supercapacitors, lithium rechargeable batteries, sensors, photovoltaic cells and photodiodes, optical limiting devices, solar cells, high-resolution printable conductors, electromagnetic absorbers and advanced transistors are among the most promising applications. Knowledge of the molecular structure of such compounds is essential for a better use, and for that reason vibrational spectroscopies are fruitful techniques. Therefore, this feature article presents recent progress in the characterization of composites based on conjugated polymers and carbon nanotubes. The contribution of Raman scattering and FTIR spectroscopy to establish the type of interaction between the two constituents will be discussed for different cases, i.e. bi-layers of polymers and carbon nanotubes, doped conjugated polymers with carbon nanotubes and covalently functionalized carbon nanotubes with conjugated polymers. In addition, surface enhanced Raman scattering (SERS) has also proven to be a suitable technique for characterization by providing signal enhancements, allowing for instance the detection of reactions at interfaces or the exploitation of properties associated with nanostructures. As an example, an extra increase of the Raman signal of a polymer deposited on a carbon nanotube thin film demonstrates the generation of surface plasmons in metallic tubes.