Revealing the time-dependent electromechanically coupled performances of viscoelastic MWCNT/polyethylene nanocomposite stress sensors

While highly sensitive elastic strain sensors have been widely investigated, the time-dependent stress sensitivity of viscoelastic MWCNT/polyethylene nanocomposite stress sensors remains to be explored. In this paper, we develop an electromechanically coupled homogenization scheme to reveal the time-dependent stress sensing performances of viscoelastic MWCNT/polyethylene nanocomposite sensors. In the time-dependent context, the complex moduli and electrical conductivity are selected as the dual homogenization parameters. The time-dependent stress sensitivity is illustrated through the viscoelastic imperfect interface connection and stress-induced tunneling distance. The predicted stress sensing capacities of viscoelastic MWCNT/polyethylene nanocomposite stress sensors are shown to be consistent with the experiments under the constant stress loading. It reveals that the stress sensitivity factor increases with the loading time under constant stress. The optimal MWCNT aspect ratio for high sensing capacities exhibits an increasing trend regarding the MWCNT volume fraction. The uncovered sensing characteristics can provide microstructural design guidance in high-performance nanocomposite stress sensors.