Electrospinning Assisted by Gas Jet for Preparing Ultrafine Poly(vinyl alcohol) Fibres

Poly(vinyl alcohol) (PVA) ultrafine fibres were prepared by gas-jet/electrospinning of its aqueous solutions. The morphology of the gas-jet/electrospun PVA fibres was investigated by controlling parameters such as: polymer solution concentration, gas flow rate and the polymer solution feeding rate. The morphology of the PVA fibres changed when the solution concentration was increased from 7 wt% to 12 wt%. With concentration of 7 wt%, a combination of smooth and some beads ultrafine PVA fibres was observed. With higher concentration, smooth fibres were obtained and the beads disappeared. The average diameters of PVA fibres increased gradually from 165±4 nm to 263±8 nm with the concentration from 7 wt% to 12 wt%. In addition, the average diameters of these ultrafine fibres were decreased from 317±10 nm to 219±5 nm after an initial increase in the gas flow rate from 2.5 L/min to 7.5 L/min and then increased to 287±9 nm as the gas flow rate increased to 10.0 L/min. The morphological structure changed with the variety of the solution feeding rates. At the solution feeding rate of 3.3 mL/h, PVA fibres with beads were observed. The average diameters of PVA fibres increased with increasing solution feeding rate. Particularly, the production rate of the gas-jet/electrospinning of PVA solution could be up to 2.2 mL/h, which was 11 times higher than the conventional electrospinning (0.2 mL/h), while the difference between the average diameter of electrospun fibres and the gas-jet/electrospun fibres was slight.