Performance evaluation of modified rotating-jet electrospinning method by investigating the effect of collector size on the nanofibers alignment

Modified rotating-jet electrospinning method (MRJM) is a new electrospinning technique with a novel setup including two metallic concentric hollow cylinders for generating highly aligned fibers. In this report, an experimental study was carried out to evaluate the effectiveness of MRJM for generating highly aligned nanofibers. For this purpose, the effect of voltage in the range of 10–22 kV, inner collector diameter in the range of 20–50 cm, and outer collector diameter in the range of 30–60 cm, on alignment degrees of electrospun fibers were explored and the results for each set of parameters were compared with those obtained for rotating-jet electrospinning method (RJM). The obtained results indicated that the alignment degrees of electrospun fibers in MRJM were significantly higher than those of RJM. The maximum achievable alignment degree in MRJM was around 82 % that was higher than the corresponding maximum value (40 %) of RJM. Although the effect of applied voltage on the degree of alignment in MRJM was observed to be negligible, it was experimentally proved that by manipulating the outer cylinder diameter, the degree of alignment can be increased up to 20 %. To achieve a conceptual understanding of the reason for significant influence of the outer cylinder on the elecrospinning performance, a formula was derived according to the Gauss’s law in the last part of this paper that relates the electric field strength inside the region between the inner cylinder and the spinneret to the radii of inner and outer cylinders.     

Modification of the rotating jet method to generate highly aligned electrospun nanofibers

The rotating jet electrospinning method has been modified to increase the amount and the degree of alignment of electrospun nanofibers. For this purpose, the cylindrical collector of the rotating jet method (RJM) was replaced by two metallic concentric hollow cylinders. We called this improved technique; a modified rotating jet method (MRJM). The effectiveness of this method was evaluated with measuring the production rate and the degree of alignment of electrospun fibers and comparison of them with those obtained for the RJM. Our results disclosed that, the MRJM can improve the degree of alignment of electrospun fibers more than two times. Furthermore, when the voltage changed from 10 kV to 22 kV the average production rate of electrospun nanofibers was increased by 41% compared with the RJM.