High performance epoxy/ MWCNTs nanocomposite sensors for multi-purpose sensing in structural health monitoring

Abstract

Structural health monitoring (SHM) is necessary for modern technical development. It can be achieved by detecting different quantities such as pressure and strain using highly sensitive and stable sensors. In this work, epoxy/multiwalled carbon nanotubes (MWCNTs) is used as sensing material to detect both strain and pressure. To ensure better performance, dispersion fabrication process was firstly optimized via electrical and microscopic measurements. Then, the piezoresistive performance such as the sensitivity, linearity, stability and drift were investigated under pressure and strain for films prepared with different carbon nanotubes (CNTs) concentration and thickness to define the optimal conditions for each sensing target.

The piezoresistive measurement shows good sensitivity to strain at very low CNTs concentration 0.3 wt. % with a gauge factor (GF = 11.094); which is around 6 times higher than conventional strain sensor, proving the efficiency of the optimized fabrication process parameters that ensure a homogenous distribution. Furthermore, the sensing layer shows also the ability to sustain high pressure load. The sensitivity is found to be highly dependent on the film thickness with higher sensitivity for thicker films in case of pressure sensing in addition to the good sensitivity at very low-pressure range. All these results prove the efficiency of Epoxy/MWCNTs as multi-purpose sensor material.