Production and Characterization of PVDF/MWCNT Core-Shell Hybrid Nanofiber Yarns via Nozzle-less Disc Electrospinning Method

In this study, the fabrication and characterization of hybrid core-shell nanofiber yarn using nozzle-less disk electrospinning method, were investigated. To identify the most suitable core structure, four types of yarns -including cotton, silk, polyester-coated Lycra, and textured polyester-were employed as the core, while the shell layer consisted of polyvinylidene fluoride (PVDF) containing 0.5, 1, and 1.5 wt% multi-walled carbon nanotubes (MWCNTs). The nanofiber yarn samples were characterized using SEM, FESEM, FTIR, and axial tensile test. Microscopy results indicated that increasing the electrospinning time from 1 to 3 minutes enlarged the yarn diameter from 18.78 to 502.45 µm, primarily due to multilayer deposition of nanofibers on the core surface. Morphological observations confirmed that increasing the MWCNT content from 0.5% to 1.5%, leads to increase in the mean nanofiber diameter from 0.152 μm to 0.210 μm; this phenomenon is due to simultaneous increases in electrical conductivity, solution viscosity, as well as nanotube aggregation at higher concentrations. Mechanical analyses showed that nanofiber coating improved the uniformity of tensile behavior, with this effect being more pronounced in textured polyester yarns because of their favorable surface structure. FTIR analysis verified the presence of the β-phase in all samples, and demonstrated that the β-phase content increases with improved dispersion of MWCNTs. Overall, the results indicate that the hybrid nanofiber yarns produced in this work—with stable structure, controlled morphology, and desirable mechanical response—are promising candidates for use in smart textiles and wearable sensing systems.