Compressive stress-electrical conductivity characteristics of multiwall carbon nanotube networks

A network of entangled multiwall carbon nanotubes is presented as a conductor whose conductivity is sensitive to compressive stress both in the course of monotonic stress growth and when loading/unloading cycles are imposed. The testing has shown as much as 100% network conductivity increase at the maximum applied stress. It indicates favorable properties of multiwall carbon nanotube networks for their use as stress-electric signal transducers. To model the conductivity-stress dependence, it is hypothesized that compression increases local contact forces between nanotubes, which results in more conductive contacts. The lack of detailed knowledge of the mechanism as well as an unclear shift from individual contacts to the whole network conductance behavior is circumvented with a statistical approach. In this respect, good data representation is reached using Weibull distribution for the description of distribution of nanotube contact resistance.