Effects of solvents on electrospun polymeric fibers: preliminary study on polystyrene

Six solvents [acetic acid, acetonitrile, m-cresol, toluene, tetrahydrofuran (THF) and dimethylformamide (DNIF)] with different properties (eg density, boiling point, solubility parameter dipole moment and dielectric constant) were used to prepare electrospun polystyrene (PS) fibers. Fiber diameters were found to decrease with increasing density and boiling point of the solvents. A large difference between the solubility parameters of PS and the solvent was responsible for the bead-on-string morphology observed. Productivity of the fibers (the numbers of fiber webs per unit area per unit time) increased with increasing dielectric constant and dipole moment of the solvents. Among the solvents studied, DMF was the best solvent that provided PS fibers with highest productivity and optimal morphological characteristics. The beadless, well-aligned PS fibers with a diameter of ca 0.7 mum were produced from the solution of 10 % (w/v) of PS in DNIF at an applied electrostatic field of 15 kV/10 cm, a nitrogen flow rate of 101 ml min(-1) and a rotational speed of the collector of 1500 rev min(-1). (C) 2004 Society of Chemical Industry.