An industrial-scale synchronized dry nanostructure spray system integrated into an electro-centrifugal jet spinning for in-situ decorating fine nanofibers

A sustainable cost-effective industrial technique for nano-scale spraying dry powders of nanostructures on nanofibers during the nanofiber spinning has been devised in this research. Nanofibers decorated with the nanostructure are produced via synchronizing the innovative dry spray system with an electro-centrifugal jet spinning. Numerous challenges involved are fully discussed and solved. The synchronized system is successfully evaluated by producing polyamide nanofibers decorated with isotropic (silver nanoparticles) and anisotropic (carbon nanotubes) nanostructures compared to the nano-colloidal processing under similar conditions. The results showed that about 97% of the nanostructures were deposited on the membrane with 88.49% washing fastness. The FE-SEM micrographs of the samples produced by the invented system demonstrated the efficient transfer of nanostructures well-dispersed on the nanofiber surfaces. Accordingly, this innovative system prevents covering nanostructures with a polymer layer and filling/ blocking their intra/inter cavities by polymer diffusion. Nanostructure surface features e.g., their interactions, surface charge, surface tension (including wetting behavior), interfaces, and activities (e.g., bioactivity, photocatalytic activities) are not affected by the polymer coverage. Accordingly, the nanofibers decorated via this system offer higher accessibility, specific surface area, efficient interface, and other features of the nanostructures attached to the surface in comparison with those produced by the nano-colloidal processing. This technique does not entail the process of colloidal solution limitations and requirements. Based on X-ray diffraction results, it prevents the possible side-effects of the solvent on the nanostructures (e.g., oxidation of Ag nanoparticles). This technique simultaneously serves as a guideline towards numerous green pathways e.g. solvent-free, waste-free efficient nano-functionalizations.