Effects of solvent on structures and properties of electrospun poly(ethylene oxide) nanofibers

Abstract

Poly(ethylene oxide) (PEO) nanofibers were prepared by electrospinning PEO solution with a mixed solvent of ethanol and deionized water. The results show that the mixed solvent system has noteworthy influences on structures and properties of electrospun PEO nanofibers, including molecular chain orientation, crystallinity degree, surface morphology, fiber diameter, diameter distribution, spinnability, and productivity. With increasing ethanol content in the mixed solvent, wrinkly morphologies appear on the surface of PEO nanofibers due to a high evaporation rate of ethanol during electrospinning process. The dielectric constant, dipole moment, conductivity, density, boiling point, and solubility parameter of the mixed solvent become lower with the ethanol content increasing. Besides, the hydrogen-bonding interactions between PEO and solvents become weaker. As a result, PEO nanofibers with larger diameters, lower molecular chain orientation, and crystallinity degree are obtained.

One‐step fabrication of superhydrophobic P(VDF‐co‐HFP) nanofibre membranes using electrospinning technique

“…During the electrospinning of DMAc solution, jet formation was observed at the tip of the needle, which suggested that the solvent had not completely evaporated between the needle and collector, leading to the non‐fiber formation due to the lack of solidification during the flight. The importance of solvents is consistent with reported effects of solvent on the spinnability of polymers, as well as on the morphology evolution and properties of electrospun membranes, according to the physicochemical properties of the solvents . Overall, the volatility, dielectric constant, dipole moment, conductivity, density, and boiling point, of the solvents may have great influences on the diameter, crystallinity, morphology and spinnability of the fibers …”

Design of polyurethane fibers: Relation between the spinning technique and the resulting fiber topology

“…The fibers are partially oriented in the horizontal direction as shown in Figure (c,e). This is due to the usage of high‐speed rotating collector in electrospinning . The strong rotational force is able to drive the fibers to align in the circumferential direction of the rotation indicated by the blue arrow as shown in Figure (c,e).…”

“…Most electrospun fibers are straight and only small traces of coiled fibers can be found in some studies . It is unique to have all coiled fibers in PU4 and high portion of coiled fibers in PU2.…”

“…Two types of collectors are used, a stationary and rotating collector as shown in Figure (a,b), respectively. For the rotating collector, a high rotating speed of ±1000 rpm is applied to increase the alignment of the fibers . The processing parameters of the electrospinning techniques are as shown in Table .…”

“…This alignment of electrospun fibers is also commonly studied in the literature. Randomly oriented fibers can be easily fabricated using stationary collectors, whereas highly aligned fibers can be fabricated using high‐speed rotating collectors . Nonetheless, tedious parameters optimization may be needed to spin highly aligned fibers with high‐speed rotating collectors as the splaying and whipping instability of the solution jet during electrospinning will hinder the alignment of the fibers as stated by Kiselev et al .…”