Characterization of the spatial elastoresistivity of inkjet-printed carbon nanotube thin films

Next-generation lightweight-designed structures shall be able to perform self-state assessment via integrated health monitoring systems. In this article a carbon nanotube(CNT)-embedded polymeric thin film is applied via inkjet-printing to perform spatial strain sensing in conjunction with using electrical impedance tomography(EIT). To gain an advanced understanding of the thin film's spatial strain sensitivity, the elastoresistivity matrix, a fourth-order tensor correlating the strain state of a conductor into its normalized change in resistivity state, is characterized. The Montgomery method is adopted to derive the planar resistivity coefficients of the thin film, and a digital image correlation(DIC) system is used to measure the planar strains. A validation test suggests that the calculated determinant of the correlated change in anisotropic resistivity shows a fairly similar result to the measured isotropic EIT reconstruction results.