Electrical impedance tomography of carbon nanotube composite materials

The field of nanotechnology is rapidly maturing into a fertile and interdisciplinary research area from which new sensor and actuator technologies can be conceived. The tools and processes derived from the nanotechnology field have offered engineers the opportunity to design materials in which sensing transduction mechanisms can be intentionally encoded. For example, singleand multi-walled carbon nanotubes embedded within polyelectrolyte thin films have been proposed for strain and pH sensing. While the electromechanical and electrochemical response of carbon nanotube composites can be experimentally characterized, there still lacks a fundamental understanding of how the conductivity of carbon nanotube composites is spatially distributed and how it depends on external stimuli. In this study, electrical impedance tomography is proposed for spatial characterization of the conductivity of carbon nanotube composite thin films. The method proves promising for both assessment of as-fabricated thin film quality as well as for twodimensional sensing of thin film response to mechanical strain and exposure to pH environments.