Effect of Solution Parameters on Spontaneous Jet Formation and Throughput in Edge Electrospinning from a Fluid-Filled Bowl

Abstract

The process of edge electrospinning relies on forming electric-field-induced instabilities (i.e., jets) in a polymer solution bath which act as sources for nanofiber production. As such, it depends on the fundamental interactions between the fluid and the electric field, which are studied in this report as a function of solution parameters (viscosity, surface tension, and conductivity). Over a wide range of conditions, experimental observations including time required for initial jet formation, total number of jets, feed rate per jet, and resultant fiber diameter are reported and compared with theoretical predictions. The presently realized fiber throughput is 40× a single needle approach while maintaining similar high fiber quality. Two distinct voltage intervals are utilized to generate many fiber-forming instabilities: a high level for jet creation and then reduced amplitude for fiber production. This dual-stage approach relies on hysteresis in Taylor cone-jet formation, wherein a larger voltage is required to create a jet-emitting cone than to maintain it.

Control of the electric field–polymer solution interaction by utilizing ultra-conductive fluids

“…2f) on the concentric collector. The jet formation process was similar to that reported for moderate conductivity solutions in a similar apparatus [50,51]. As summarized in Fig.…”

“…Previous work on unconfined electrospinning and analysis of electric field-driven processes in general indicates that the feed rate through a jet can be estimated to scale as d 2 E 2 /h where E is the electric field, d the jet diameter and h the viscosity [51,52]. There is no indication of significant changes in h versus shear rate with salt concentration (see Supplementary Fig.…”

Preparation and characterization of poly(vinyl alcohol)/graphene nanofibers synthesized by electrospinning

“…The more conducting the solution is the better chance of getting thinner fibers. Thus incorporation of graphene into PVA solution enhanced the conductivity of the solution to be electrospun and because of this improved conductivity the resulting fibers became thinner compared to fibers produced with non-conducting material such as PVA [1,3,33,34]. To further confirm the presence of the graphene filler in the fibers, some fibers were physically broken by carefully scratching the fibers by razor blade to reveal the graphene nanofillers inside the fibers and this is shown in figure 6 for GF foam nanofiller with the concentration of 0.08 g as an example.…”

A review on electrospun bio-based polymers for water treatment

“…By that time the technique was called 'electrostatic spinning'. The considerable interest in the electrospinning technique in the 1990s resulted in the new name 'electrospinning' [40,41]. The name 'electrospinning' was then accepted and is now widely used in the literature as a description of this viable technique to produce ultrathin fibres from a polymer solution or melt through application of electrical forces.…”

“…Also, nanofibres with mean diameters ranging from 100 to 400 nm, were obtained. In the bowl-edge unconfined process, the primary interaction between the electric field and the polymer solution caused fluid perturbations within the bath reservoir filled with polymer solution [31,41]. These fluid perturbations were responsible for Raleigh-Taylor instabilities formed by gravity forces in the polymer solution.…”