Multifunctional nanocomposite assessment using carbon nanotube fiber sensors

Here, a novel technique utilizing carbon nanotube fibers (CNTFs) for the one-step, dual-stage, non-destructive monitoring of multifunctional nanocomposites is proposed. Nanocomposites with single- and multi-walled carbon nanotubes with concentrations of 0.25 and 0.75 % wt. were evaluated. CNTFs were embedded into the nanocomposites during their manufacturing to monitor changes (1st stage), and were left embedded to also monitor their lifecycle (2nd stage). Monitoring sensitivity and reliability dependence on CNTF diameters (∼40–700 μm), electrical conductivity (∼10 2 –10 4 S/m), and the choice of measurement technique (2- and 4-point) were investigated. Promising sensitivity to CNT type and concentration was seen during the 1st stage, with measurements being independent of CNTF diameter, contact resistance, and displaying low noise. For the 2nd stage, nanocomposite electrical and mechanical (tensile and cyclic) properties were determined in both static and dynamic conditions. The CNTFs did not cause any reduction in mechanical performance, unlike the losses observed for metallic electrodes (up to 60 % reduction in ultimate tensile strength). CNTF-based evaluation of the electrical resistivity (between 10 2 — 10 6 Ohm∙cm) and dynamic electrical response (gauge factors between ∼3 and 13) matched values from a standard electrode material. Microstructural analysis and molecular dynamics simulations proved that this unique performance was due to the synergistic interfacial interaction of the dispersed CNTs with the CNTFs. These findings show that CNTFs may be used to accurately monitor nanocomposite multifunctional properties both during manufacturing and application using one-step integration, regardless of size and manufacturing technology . • A novel technique for nanocomposite dual-stage monitoring using CNTFs was developed. • Multifunctional property measurements are independent of CNTF characteristics. • Nanoparticle type, concentration and measurement method do not affect sensitivity. • Measurements can be made on polymers with a large range of mechanical properties. • The technique causes no mechanical property loss.