Concept of minimum electrospinning voltage in electrospinning of polyacrylonitrile N,N‐dimethylformamide system

Abstract

Polyacrylonitrile solutions in N,N-dimethylformamide (DMF) were electrospun into nanofibers by charging the polymer fluid in an electric field. Controlled experiments were performed using a needle type spinneret to investigate the effect of various electrospinning parameters on the percentage conversion of polymeric fluid into fibers and on fiber diameter obtained. It was found that when the polymeric fluid was continuously fed at a constant rate, application of a minimum electrospinning voltage (MEV) was necessary to ''completely'' convert the ejected fluid into nanojets to form nanofibers. Also, that the maximum amount of splitting or elongation that a polymeric fluid could undergo was primarily dependent on number of entanglements per chain in the fluid. This resulted in obtaining nanofibers with a particular diameter irrespective of the values of important electrospinning variables such as applied voltage, flow rates, and distance between the electrodes. On the other hand, MEV, necessary to obtain full conversion into nanofibers, was found to be strongly dependent on the spinning parameters and was unique for a given set of parameters. The significance of the MEV was evident from the fact that the square of the MEV, which is a measure of the electrical energy utilized by the system, was found to be directly proportional to the rate of formation of fiber surface area during the electrospinning process.

Molecular dynamics study of response of liquid N,N-dimethylformamide to externally applied electric field using a polarizable force field

“…The van der Waals (vdW) intramolecular, E vdw-intra , and vdW intermolecular interaction, E vdw-inter , of each molecule in the box were calculated and their average together with the minimum and maximum values are given in Table III. The heat of vaporization, H vap was calculated from the total intermolecular potential energy of the liquid, E inter (l), the intramolecular energies of the liquid, E intra (l), and the gaseous phase, E intra (g), and the PV component by Eq. (1). E inter (l) was computed over all the intermolecular energies at a cutoff of 12.5 Å. E intra (g) was determined by excluding the binding energy obtained by QM calculation at the MP2/aug-cc-pvtz level 63 from the AMOEBA energy of a gas phase dimer 46 :…”

Investigation on jet stability, fiber diameter, and tensile properties of electrospun polyacrylonitrile nanofibrous yarns

“…It is believed that the drawback of prolonged heating time can greatly be resolved if the fiber diameter is significantly reduced. 37,49,50 The mechanical behavior of electrospun nanofibers is expected to differ from bulk and microscale fibers due to their fabrication process and large surface to-volume ratio. 48 Thus, the preparation of PAN nanofibers is of great interest to the scientists.…”

“…Many researchers have worked on the electrospinning of PAN/DMF solution and have obtained electrospun PAN fibers with diameters in the range of 100-2700 nm depending on various electrospinning parameters. 37,[49][50][51][52] While significant insights have been achieved, there is still inconsistency in the findings of the influence of electrospinning voltage and flow rate on the diameter of the PAN nanofiber. 37,49,50 The mechanical behavior of electrospun nanofibers is expected to differ from bulk and microscale fibers due to their fabrication process and large surface to-volume ratio.…”

“…37,[49][50][51][52] While significant insights have been achieved, there is still inconsistency in the findings of the influence of electrospinning voltage and flow rate on the diameter of the PAN nanofiber. 37,49,50 The mechanical behavior of electrospun nanofibers is expected to differ from bulk and microscale fibers due to their fabrication process and large surface to-volume ratio. Papkov et al 53 investigated the tensile property of individual electrospun PAN fibers for a large range diameters.…”

Electrospun composite nanofibres of PVA loaded with nanoencapsulated n-octadecane

“…[1][2][3][4][5] The advantages of electrospinning include production of ultrathin bres with large surface area and superior properties. [1][2][3][4][5] The advantages of electrospinning include production of ultrathin bres with large surface area and superior properties.…”