抄録
In this study, we fabricated a piezoelectric strain sensor from multi-walled carbon nanotubes (MWNTs) and PVDF nanocomposites, i.e., PVDF/MWNT for measuring dynamic strains. The influence of MWNT loading on the sensor performance was evaluated by changing the MWNT loading as 0.0wt%, 0.05wt%, 0.2wt%, and 0.3wt%. To increase the MWNT dispersion in PDVF matrix, a mixing process by using a planetary stirring machine and sonication processing by using an ultrasonic mixer were firstly employed together to produce the nanocomposite films. Then, these films were stretched under uniaxial loading and poled under 60MV/m to fabricate the strain sensors. Moreover, crystallinity of the PVDF/MWNT nanocomposites was analyzed by using X-ray diffraction (XRD) analysis, and the fractured surfaces of the pre-stretching PVDF/MWNT nanocomposites were observed by using a polarized optical microscope (POM). In this research, the piezoelectricity and signal tracking capability for the PVDF/MWNT nanocomposites sensors in vibration were investigated. From the experimental results, the piezoelectricity, i.e., the sensor output voltage of the PVDF/MWNT nanocomposites reaches to a maximum peak value at 0.05wt% MWNT loading, and then decreases with further more addition of MWNTs. The result of XRD intensity was consistent with the result of the piezoelectricity of PVDF/MWNT nanocomposites. From POM observations, compared to that of pure PVDF, the spherulite size of the PVDF/MWNT nanocomposites becomes smaller. Moreover, there might be an optimum content of MWNTs in the nanocomposites, which can result in high piezoelectric properties of the nanocomposite strain sensors.
