Highly aligned and single-layered hollow fibrous membranes prepared from polyurethane and silica blends through a two-fluid coaxial electrospun process

Highly aligned, single-layered hollow fibrous membranes are prepared using two-fluid coaxial electrospinning (ES). Polyethylene oxide (PEO) is used as the core, and polyurethane (PU) and blends of PU with silica (SiO₂) are used as the shell to extract the PEO. The effects of the polymer-complex concentration, the ES parameters, and the SiO₂ blending ratio on the morphologies and mechanical properties of fibers are explored. Using an appropriate PU concentration and applied spinning voltage combination yields a high fiber-alignment degree. The hollow fibrous average area increases as the inner-to-outer flow-rate ratio (FRR_i/o) increases because the inner flow increases. When using a PU concentration of 13 wt%, a spinning voltage of 7 kV, and an FRR_i/o of 0.8, along with blending 15% SiO₂ with PU, the fiber alignment of the PU/SiO₂ membranes is 95%. The Young's modulus indicates that adding SiO₂ enhances the mechanical properties, causing a monolayer hollow-fiber assembly with interconnected fibers to form.