Conductive probe microscopy investigation of electrical and charge transport in advanced carbon nanotubes and nanofibers-polymer nanocomposites

In this chapter, the main scanning probe microscopy-based methods to measure the transport properties in advanced polymer-Carbon Nanotubes (CNT) nanocomposites are presented. The two major approaches to investigate the electrical and charge transport (i.e., Electrostatic Force Microscopy [EFM] and Current-Sensing Atomic Force Microscopy [CS-AFM]) are illustrated, starting from their basic principles. First, the authors show how the EFM-related techniques can be used to provide, at high spatial resolution, a three-dimensional representation CNT networks underneath the surface. This allows the studying of the role of nanoscopic features such as CNTs, CNT-CNT direct contact, and polymer-CNT junctions in determining the overall composite properties. Complementary, CS-AFM can bring insight into the transport mechanism by imaging the spatial distribution of currents percolation paths within the nanocomposite. Finally, the authors show how the CS-AFM can be used to quantify the surface/ bulk percolation probability and the nanoscopic electrical conductivity, which allows one to predict the macroscopic percolation model.