Carbon Nanotubes and Graphene - Research and Applications

Nano-composite made by two different dispersion procedures has been considered to investigate the distribution of multi-walled carbon nanotubes within an epoxy resin. The correlation between the electrical conductivity of the epoxy/MWNTs composite and nanotube dispersion has been carried out using an eddy-current technique (ECT) based on an induction coil probe.

- the EC image is capable to distinguish the spatial inhomogeneities between the nanotubes bundles and the presence of interconnected nanotubes, as confirmed by optical transmission microscopy images;
- there is a correlation between the nanotube dispersion, within the polymer matrix, and the increasing of the electrical conductivity. It could be noted that the electrical conductivity of the epoxy polymer matrix is generally of about 10^(-9) S/m while the electrical conductivity measured for the specimens D and E, loading with 0.1% of nanotube, is 0.8 S/m. Therefore, the dispersion procedure adopted for the samples D and E enhances effectively the electrical conductivity of the polymer matrix. This is an important result for the potential application of the nanotube loaded epoxy system to build components capable of dissipating electrostatic charge or shielding devices from electromagnetic radiation.

This work confirms the capability of the eddy current testing based on the use of an induction coil to evaluate in contactless, fast and non destructive way, the anisotropy distribution of CNTs due to the manufacture processing.
Article to be published in NDT & E International (C. Bonavolontà, et al., 2008).

In this study, researchers demonstrate the synthesis of carbon nanotubes (CNTs) on clay minerals, and the development of biosensors based on Nafion-CNT/Clay-Au and Nafion-CNT/Clay-Au-Glucose oxidase (GOD) composite films for the detection of hydrogen peroxide (H2O2) and glucose, respectively. The CNTs are synthesized on nickel cation exchanged clay mineral platelets. From field-emission scanning electron microscope images, X-ray diffraction, Fourier transfer infrared and thermogravimetric analysis results, the clay layers are exfoliated and delaminated after the growth of CNTs on them. The mixed hybrid film of Nafion, CNT/Clay, Au particles and GOD is coated on the glassy carbon (GC) electrode to detect H2O2 or glucose. This film exhibits a detection limit of 5.0 × 10–5 M for H2O2 with a sensitivity of 280 nA mM–1. In addition, the amperometric response for glucose containing 2.0 mg mL-1 GOD in the Nafion-CNT/Clay-Au-GOD modified GC electrode exhibits a sensitivity of 620 nA mM-1 with a linear range up to 1850 μM. A higher sensitivity and shorter response time are observed with increasing GOD content in the composite matrix film. Besides, the highest sensitivity of 2032 nA mM-1 is obtained with the addition of the 10.0 mg mL-1 GOD in the composite film. Consequently, the CNT/Clay/Nafion medium can probably be a useful electrode for the development of sensors due to its high sensitivity and applicability.