The main limitation of electrospinning process is a low nanofibers production rate. Since 1934, when Fromhals introduced the electrospinning to wider public by submitting a patent application for the technique, researchers have been investigating possibilities of its’ industrial usage [
1]. On the laboratory scale, the electrospinning allows to produce ultrafine nanofibers with rates sufficient enough to conduct experiments. It means that using polymer solution feed rate in the range from about 0.2 ml∙h
−1 to about 2 ml∙h
−1 in a single-jet electrospinning system fibers can be produced with a rate from about 0.01 to about 0.1 g∙h
−1 [
2,
3]. Other obstacles with industrial application of electrospinning are the high voltage requirement and humidity influence of the fibers properties. Even though the industrial application of the electrospinning is limited, nanofibrous structures generated by this technology gathered attention of specialists from various fields, for instance filtration [
4,
5], chemical catalysis [
6,
7], electronics and energy storage [
8,
9], tissue engineering [
10‐
12], and the like.
To overcome the low throughput of electrospinning, and provide large scale process for abovementioned specialists, various approaches have been reported to scale up nanofiber production. These approaches might be named as multi-jet techniques. Zheng et al. summarized these approaches to electrospinning scale up in three categories [
13]: multineedle electrospinning [
14,
15], multihole electrospinning [
16,
17], and free surface electrospinning [
18,
19]. Even though above approaches allow improvement in nanofibers production rate by electrospinning, there is an important issue with multi-jet electrospinning – the deviation of the angle of the jets form the axis of the electrospinning system caused by mutual electrostatic repulsion. The use of more than one nozzle for polymer solution supply in multi-jet electrospinning causes the electric field deviation that leads to jets repulsion and angle deviation of the jets. The deviation of multi-jet electrospinning jets also causes instability problems such as dripping of polymer solution and fiber collection difficulties [
3]. Working on single-jet electrospinning process, Deitzel et al. proposed application of additional rings to stabilize the electric field [
20], and this approach inspired variety of configurations for multi-jet electrospinning to modify and control the process. Kim et al. introduced multi-jet electrospinning system with additional cylindrical electrode surrounding the nozzles system [
21]. Another modification by additional electrodes in multi-jet process was an auxiliary electrode. Placed in parallel to the collector, either supporting the nozzles [
15,
22], or working as additional collector [
23], the auxiliary electrode controls the electric field uniformity in the multi-jet electrospinning process. Tomaszewski and Szadkowski, and Yang et al. suggested that appropriate nozzles distribution in multi-jet electrospinning system facilitates collecting process of nanofibers [
24,
25]. In their review paper, Ramakrishnan et al. described another approach to multi-jet needleless electrospinning called bubble electrospinning [
26]. In this process, carrier gas is pushed through the polymer solution forming bubbles. When a bubble bursts at the surface of the polymer solution, the polymer jet is formed in electrostatic field. Another approach to overcome the instabilities of polymer jet in electric field for the single-jet electrospinning also involves usage of the gas and includes application of high speed air stream. Several groups used this approach to control the production and the collecting process in a simple single-jet electrospinning system. This approach was also used to improve the nanofibrous product quality [
27‐
29]. Even though, the last two abovementioned approaches are not specific for overcoming the mutual repulsion effect, the application of, so called, assistance of sheath gas was inspired and reported to be used in multi-jet electrospinning systems [
30]. Process presented by Yu et al. involves the application of air stream in the way similar to the solution blow spinning process – another method for nanofibers production [
31] – where each spinneret is built in a way allowing the use of gas stream individually. This approach gives a control over each polymer solution jet separately, but leaves the problem of non-uniform collection of the nanofibers mat on the surface of the collector.
Our previous study shows that application of air stream in nanofibers producing processes may play a crucial role, especially when it is the only source of a driving force for the process [
32]. In present work, we introduce the air blowing assistance to multi-jet electrospinning process. Application of the multi-jet electrospinning system was intended to improve the electrospinning throughput. The aim of present work is to present a new way to overcome electrostatic mutual repulsion of the polymer jets by the application of sheath gas surrounding multi-jet electrospinning spinneret using specifically designed system. The effect of the reduction of the repulsive interactions of polymer jets was investigated. This effect was measured by the size of collection area of the nanofibrous mat on the surface of the collector, and comparison of the products obtained in two modes multi-jet electrospinning and blow-assisted multi-jet electrospinning was made. What is more, we investigated how the modification of the multi-jet electrospinning process by blowing assistance influences the nanofibers quality – fibers morphology and fibers mean size.