Direction sensitive deformation sensing with CNT/epoxy nanocomposites

In this work direction sensitive bending strain sensors consisting of a single block of epoxy/multi-wall carbon nanotube composite were developed. The nanocomposite electrical resistance correlates closely with mechanical strain. The directional sensitivity to bending deformations is related to the change in electrical resistance, which becomes positive or negative, depending on the direction of bending deflection. This effect is brought about due to all inhomogenous distribution of electrical conductivity throughout the material. The production process was performed in a straightforward single-step processing route. In a modified setup the resistance change of the nanocomposite is related to exclusively compressive loads or tensile loads. A characterisation of the conductivity distribution within the produced material was done in order to find the driving forces behind the phenomenon.