Strategies for the optimization of carbon nanotube/polymer ratio in composite materials: Applications as voltammetric sensors

Multiwall carbon nanotubes and resin epoxy have been used to fabricate a composite electrode for electroanalytical purposes. The optimum composite proportions for high electrode sensitivity, low limit of detection and fast response were investigated. Compositions were characterized by percolation theory, electrochemical impedance spectroscopy, cyclic voltammetry, scanning electron microscopy, atomic force microscopy and chronoamperometry. We found that around the optimum composite proportion, the electrode performance is less affected by small variations in the composition of the composite. These composite electrodes provide easy surface renewal, low background current, an efficient mass transport and are suitable for chemical modification. The potentiality of this approach in terms of electroanalytical response is demonstrated by means of the amperometric detection of ascorbic acid in water solution.