Effect of MWCNT content on the mechanical and piezoelectric properties of PVDF nanofibers

Abstract In this study, the mechanical properties and morphology of aligned and random polyvinylidene fluoride (PVDF) fibers as well as the morphology and mechanical, piezoelectric, and thermal properties of PVDF fibers with different multi-walled carbon nanotubes (MWCNT) contents were analyzed. Although electrospun piezoelectric PVDF-based nanofibers have been extensively studied for application in wearable devices, they do not have sufficient flexibility and strength for practical application. Therefore, in this study, the effects of various experimental parameters, such as MWCNT content and fiber orientation, on the mechanical and piezoelectric properties of PVDF nanofibers were investigated in depth. Scanning electron microscopy analysis revealed that the average diameter of the PVDF nanofibers decreased with an increase in degree of orientation, while transmission electron microscopy analysis revealed the uniform dispersion of MWCNTs in the PVDF nanofibers. The PVDF nanofibers containing 0.008 wt% MWCNTs exhibited an excellent tensile strength. Furthermore, Fourier transform infrared spectroscopy analysis revealed that the β-phase fraction increased with increasing MWCNT content. The thermal stability of the nanofibers increased with an increase in β-phase fraction, as evidenced by the increase in melting and initial decomposition temperatures and decrease in weight loss determined by differential scanning calorimetry and thermogravimetric analysis.