Carbon nanotube fibers as high-fidelity sensors for carbon nanotube/polymer nanocomposites

Carbon nanotube fibers (CNTFs) enable real-time dual-stage monitoring of CNT/epoxy nanocomposites via single-step embedding during manufacturing. Although highly sensitive, CNTF responses can be influenced by environmental and processing factors that introduce sensor artifacts and response lag. Here, we quantitatively assess, for the first time, the accuracy of CNTF sensing in multifunctional epoxy nanocomposites. CNTFs were fabricated via the wet-pulling of single-walled CNT (SWCNT) thin films (18, 39, and 59 nm thickness) and embedded in epoxy containing 0.005 and 0.5 wt. % single- and multiwalled CNTs (MWCNTs). Electrical measurements were conducted using 2- and 4-point techniques. CNTFs showed negligible measurement inaccuracy of less than 10⁻⁶% and 10⁻¹% for MW- and SWCNT nanocomposites, respectively. Owing to their virtually contact-resistance-free behavior, CNTFs achieve 1–2 orders of magnitude higher accuracy than standard surface-applied electrodes. These results establish CNTFs as high-fidelity, low-artefact sensors capable of monitoring multifunctional epoxy nanocomposites better than existing techniques.