Assessing the electrical behaviour of MWCNTs/epoxy nanocomposite for strain sensing

Abstract Nanocomposite sensors are gaining importance not only because they have low cost, but also because of the possibility to adjust sensor properties to the requirements of certain applications. In this paper, we focus on the realization of multiwalled carbon nanotubes (MWCNTs)/epoxy nanocomposite for strain sensing applications. We propose to use a simple direct mixing process to realize randomly distributed nanocomposite films with different concentration ranging from 0.3 to 0.75 wt.% and thicknesses. Dispersions were firstly examined using scanning electron microscopy (SEM). The results show a good homogeneity and distribution of the MWCNTs in agreement with the reduced electrical resistance when increasing the CNTs content and film thickness. Additionally, it has been demonstrated that the piezoresistive characteristic of nanocomposites depends principally on the CNTs content and film thickness. A higher magnitude of change in resistance is observed for the sample with low volume fraction and thickness leading to a gauge factor 14.19 with a linearity correlation of R 2 = 0.9414. In this work, we address also the effect of environmental changes by characterization of temperature, humidity and stability behaviour. These films show higher sensitivity to temperature and humidity at lower MWCNTs concentration. The film resistance shows a good stability under ambient conditions.