Effect of a Room-Temperature Ionic Liquid on the Structure and Properties of Electrospun Poly(vinylidene fluoride) Nanofibers

Novel anti-static nanofibers based on blends of poly(vinylidene fluoride) (PVDF) and a room-temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], were fabricated using an electrospinning approach. The effects of the RTIL on the morphology, crystal structure, and physical properties of the PVDF nanofibers were investigated. Incorporation of RTIL leads to an increase in the mean fiber diameter and the rough fiber surface of the PVDF/RTIL composite nanofibers compared with the neat PVDF nanofibers. The PVDF in the PVDF/RTIL nanofibers exhibits an extremely high content (almost 100%) of β crystals, in contrast to the dominance of PVDF γ crystals in bulk melt-blended PVDF/RTIL blends. Nonwoven fabrics produced from the electrospun PVDF/RTIL composite nanofibers show better stretchability and higher electrical conductivity than those made from neat PVDF without RTIL, and are thus excellent antielectrostatic fibrous materials. In addition, RTIL greatly improved the hydrophobicity of the PVDF fibers, enabling them to effectively separate a mixture of tetrachloromethane (CCl4) and water. The extremely high β content, excellent antielectrostatic properties, better stretchability, and hydrophobicity of the present PVDF/RTIL nanofibers make them a promising candidate for micro- and nanoscale electronic device applications.