Free surface electrospinning from a wire electrode

Abstract

Electrostatic jetting from a free liquid surface offers an alternative to conventional electrospinning in which jets are emitted from spinnerets. In this work we analyze a system in which a wire electrode is swept (in a rotary motion) through a bath containing a polymeric solution in contact with a high voltage, resulting in entrainment of the fluid, the formation of liquid droplets on the wire and electrostatic jetting from each liquid droplet. Solutions of polyvinylpyrrolidone in ethanol were used as test systems to evaluate each stage of the process.The volume of individual droplets on the wire were measured by photographic methods and correlated with the viscosity, density and surface tension of the liquid, and with system parameters such as electrode rotation rate and wire diameter. The local electric field in the absence of liquid entrainment was modeled using conventional electrostatics, and jet initiation was found to occur consistently at the angular position where the electric field exceeds a critical value of 34 kV/cm, regardless of rotation rate. Two operating regimes were identified. The first is an entrainment-limited regime, in which all of the entrained liquid is jetted from the wire electrode. The second regime is field-limited, in which the residence time of the wire electrode in an electric field in excess of the critical value is too short to deplete the fluid on the wire. The productivity of the system was measured and compared to the theoretical values of liquid entrainment. As expected, highest productivity occurred at high applied potentials and high rotation rates.

A Review of Electrospun Carbon Fibers as Electrode Materials for Energy Storage

“…There are limitations on the types of materials that can be fabricated by electrospinning, and it is sometimes difficult to formulate solutions with the 34 are possible strategies to increase productivity and achieve large scale nanofiber production.…”

“…Alternatively, jets can be generated from free liquid surfaces such as films, drops or bubbles, without the need for a spinneret; the subsequent acceleration, whipping and solidification to form fibers is similar to those in the conventional technique. 34 The often-cited advantages of electrospinning include ease of operation, efficiency, low cost, high yield, and high degree of reproducibility of the obtained materials. The versatility of electrospinning is reflected in the nature of electrospinnable materials as well as the different forms of fiber assemblies and architectures.…”

Production of core/shell fibers by electrospinning from a free surface

“…Nevertheless, for the results reported here, experiments were limited to 20 minutes or less and were performed in a closed chamber with a temperature ranging from 21-24 °C and a relative humidity less than 2%. Further details of the experimental apparatus may be found in ref 18 (Forward and Rutledge, 2012).…”

“…1(a). This process has been studied previously for a liquid bath comprising a single liquid (Forward and Rutledge, 2012). We introduce a new bath configuration comprising two immiscible liquids, layered one on top of the other.…”

Needleless Electrospun PVA/Chitosan Nano Fiber Membrane and its Antibacterial Property

“…Needleless electro spinning could solve the above problems and make industrialization possible. The main techniques for needleless electro spinning currently are tip electro spinning of the liquid surface [8][9][10][11][12][13][14], conical wire coil spinnerets [15], multi-hole/porous spinnerets [16][17][18] and rotary cylinder/cone/ disk spinnerets [19,20]. Designed a perforated pipe needleless electrostatic spinning apparatus [21].…”