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"Electrospinning Process and Applications of Electrospun Fibers" Jayesh Doshi and Darrell H. Reneker http://dx.doi.org/10.1016/0304-3886(95)00041-8
 * Summary of Article for Research Paper**
 * 1) Abstract
 * Electrospinning is a polymer processing method that utilizes an applied voltage to drive the charged polymer onto a collector plate. Different fiber morphologies are obtained by varying the electrospinning parameters.
 * 1) Introduction
 * The electrospinning process has been used in industry, however, this paper is attempting to identify the parameters that affect the electrospinning process and will provide preliminary results.
 * An electric field is applied to a polymer solution held in a capillary which in turn has an induced charge and a conical shape (Taylor cone) forms at the end of the capillary. When surface tension of the polymer is overcome, the polymer jet travels to a collection plate and the solvent evaporates while traveling to the plate.
 * Potential parameters that affect the electrospinning process include solution properties, ambient conditions, and controlled variables.
 * Various polymer/solvent systems were utilized in a study that varied the identified parameters. The high surface area to volume ratio of electrospun polymers allows them to be used in a variety of applications, such as separation membranes or wound dressings.
 * 1) Description of apparatus
 * The setup included a glass capillary tube filled with a polymer solution. The metal electrode was inserted into the solution and an air pump was used to drive the solution out of the tube where it was electrospun onto various grounded collector plates.
 * 1) Experimental method and material
 * Aqueous solutions of 1450kDa polyethylene oxide (PEO) were prepared (1wt%-7wt%) and conductivity, surface tension, and viscosity were measured for each solution.
 * By varying the electric potential, hydrostatic pressure, and distance between the capillary tip and collector plate a stable jet of PEO was obtained during electrospinning. Wet or dry fibers were also obtainable by varying the distance between the capillary tip and collector plate.
 * Transverse electric fields created via two metals plates deflected the very charged PEO onto a collector plate with deflections of up to 15 degrees.
 * The required electric potential to start the electrospinning process as well as the potential at which electrospinning stops were determined by slowly increasing and decreasing the applied electric potential until a Taylor cone formed and disappeared.
 * The diameter of the polymer jet was determined via laser light scattering. The decreased jet diameter as it travels through the air results in higher surface charge density ultimately creating multiple smaller jets.
 * 1) Results and discussion
 * PEO fibers were obtained from solutions with viscosity ranging from 800 to 4000 centipoise, surface tension of 61 dynes/cm, and conductivity of 400 microSiemens/cm.
 * From a PEO solution of 4wt%, ejection of the polymer jet starts around 10^7 V/m. When the electric potential is increased above that value, the jet becomes unstable and multiple jets formed, suggesting that the ejection is not dependent on the shape of the polymer tip (Taylor cone).
 * Positive and negative potentials were both used in successful fiber formation. The typical amperage of the electrospinning process was determined to be 100nA and a curved collector plate was most efficient at collecting the fibers.
 * As the concentration of the PEO solution is increased, both the potential required to start the electrospinning process and the potential at which the electrospinning process no longer takes places are increased.
 * For an applied electric potential of 10kV, as the distance from the Taylor cone increased, the diameter of the 4wt% PEO polymer jet decreased.
 * The elongational flow of the polymer during the ejection of the jet results in the polymer molecules to orient in the extended form.
 * The increased surface charge density as the jet travels through air results in splitting of the polymer jet and multiple parameters, such as electric field strength and surface tension, affect the splitting.
 * Optical microscopy and scanning electron microscopy were utilized to evaluate the fiber morphologies. The orientation, fiber diameter, and cross-sectional shape of the fibers can be altered by changing the identified process parameters.
 * Electrospun fiber composites can be created by electrospinning layers of different polymers on top of each other. Potential applications of the electrospun fibers include production of nonwoven textiles, reinforcing fibers in composites, or as a support for thin polymeric separation membranes.
 * 1) Conclusion
 * Polymer fibers were successfully electrospun with various morphologys obtained by altering the process parameters. These fibers may be of interest to multiple industries such as the agricultural or medical fields.