Spatial conductivity mapping of carbon nanotube composite thin films by electricalimpedance tomography for sensing applications

Abstract

This paper describes the application of electrical impedance tomography (EIT) todemonstrate the multifunctionality of carbon nanocomposite thin films under various typesof environmental stimuli. Carbon nanotube (CNT) thin films are fabricated by alayer-by-layer (LbL) technique and mounted with electrodes along their boundaries. Theresponse of the thin films to various stimuli is investigated by relying on electric currentexcitation and corresponding boundary potential measurements. The spatial conductivityvariations are reconstructed based on a mathematical model for the EIT technique.Here, the ability of the EIT method to provide two-dimensional mapping of theconductivity of CNT thin films is validated by (1) electrically imaging intentionalstructural defects in the thin films and (2) mapping the film’s response to various pHenvironments. The ability to spatially image the conductivity of CNT thin filmsholds many promises for developing multifunctional CNT-based sensing skins.