Controlled wall thickness and porosity of polymeric hollow nanofibers by coaxial electrospinning

Abstract

Highly porous polymeric hollow nanofibers were developed using a method based on coaxial electrospinning with inner silicon oil and outer polymer solutions. This method was verified by the fabrication of polymeric hollow fibers, whose diameter and wall thickness could be varied by controlling the coelectrospinning parameters, such as the dielectric constant of the solvents, concentration of the polymer solution, molecular weights of the polymers and viscosity of the inner silicon oil phase. The entire diameter and wall thickness of the hollow fibers could be varied from 5 to 15 µm and 180 to 900 nm, respectively. Highly porous polymeric hollow nanofibers were fabricated by coaxial electrospinning with a highly volatile solvent. The interior surface was quite smooth without pores. Therefore, pore formation occurred at the outer surface of the hollow fibers due to rapid solvent evaporation because the jet only occurred between the surface of the polymer solution and air. The smooth interior and highly porous outer surface, circular crosssection and uniform size of the hollow polymer nanofibers are expected to have attractive applications in areas, such as catalysis, optoelectronics, nanofluidics, drug delivery or biosensorics.

Highly Compliant Vascular Grafts with Gelatin-Sheathed Coaxially Structured Nanofibers

“…4 The high ratio of the surface area to volume or to the mass of these fibers is highly advantageous in biomedical applications such as tissue engineering and drug delivery. 5–8 …”

Controlled gentamicin release from multi-layered electrospun nanofibrous structures of various thicknesses

“…1,[16][17][18] However, the electrospinning technique allows the production of continuous polymeric nanofibers and provides numerous opportunities to modify and control their Dovepress submit your manuscript | www.dovepress.com morphological parameters, such as surface area, fiber diameter, the porosity of the nanofibrous layer (fiber density), basis weight, 19 or internal fiber structure. 18,20,21 Nanospider™ electrospinning technology is based on a needleless method in which polymeric jets are spontaneously formed from liquid surfaces 22,23 and allows the production of fibers with diameters ranging from tens of nanometers to tens of micrometers. Nanospider™ (Elmarco, Liberec, Czech Republic) technology is very flexible, enabling the formation of nanofibrous materials from various polymers.…”

Flexible hollow nanofibers: Novel one-pot electrospinning construction, structure and tunable luminescence–electricity–magnetism trifunctionality

“…In many cases, nanofibers with hollow structure were prepared by coaxial electrospinning technique, in which coaxial spinnerets replace the single spinneret in the conventional setup for electrospinning, followed by appropriate post-treatment, such as core solvent extracting or calcination process. Lee et al [59] developed highly porous polymeric hollow nanofibers using a method based on coaxial electrospinning with inner silicon oil and outer polymer solutions, and then the silicon oil was extracted by soaking the fibers in n-hexane overnight. Li et al [60] successfully synthesized YF 3 :Eu 3+ hollow nanofibers via fluorination of the relevant Y 2 O 3 : Eu 3+ hollow nanofibers which were obtained by calcining the coaxial electrospun core-sheath composite nanofibers.…”