Elcctrospiiming is a straightforward method to produce micro/nanoscale fibers from polymer solutions typically using an operating voltage of 10 kV 30 kV and spinning distance of 10 cm 20 cm. In this paper, polyvinyl pyrrolidone （PVP） non-woven nanofibers with diameters of 200 nm 900 nm were prepared by low-voltage near-field electrospinning with a working voltage of less than 2.8 kV and a spinning distance of less than 10 mm. Besides the uniform fibers, beaded-fibers were also fabricated and the formation mechanism was discussed. Particularly, a series of experiments were carried out to explore the influence of processing variables on the formation of near-field electrospun PVP nanofibers, including concentration, humidity, collecting position, and spinning distance.
Fluorescein/polyvinyl pyrrolidone （PVP） composite nanofibers with different fluorescein loadings （with a weight concentration of 0-5.0%） are fabricated via electrospinning. Morphologies, structures and photoluminescent （PL） prop- erties of these straight, helical or wavelike fibers are characterized by scanning electron microscopy （SEM）, fluorescence microscopy and a spectrophotometer. It is found that the maximum emission of the as-spun fluorescein/PVP fibers occurs at 510 nm. The PL intensity of the composite fiber increases with fluorescein concentration, then fluorescence quenching appears when the concentration reaches 1.67%. The mechanism of fluorescence quenching of fiuorescein is discussed. In addition, the composite fibers exhibit a much stronger PL intensity than fluorescein/PVP bulk film owing to larger specific surface area, which makes them promising materials for biomedical applications such as probes and sensors.
Electrospinning is a straightforward method to produce micro/nanoscale fibers from polymer solutions typically using an operating voltage of 10 kV–30 kV and spinning distance of 10 cm–20 cm. In this paper, polyvinyl pyrrolidone (PVP) non-woven nanofibers with diameters of 200 nm–900 nm were prepared by low-voltage near-field electrospinning with a working voltage of less than 2.8 kV and a spinning distance of less than 10 mm. Besides the uniform fibers, beaded-fibers were also fabricated and the formation mechanism was discussed. Particularly, a series of experiments were carried out to explore the influence of processing variables on the formation of near-field electrospun PVP nanofibers, including concentration, humidity, collecting position, and spinning distance.
