Electrospinning Case Study

Polyacrylonitrile (PAN) (MW: 80,000 g/mol) was purchased from Polyacryl Company (Iran). Dimethylformamide (DMF) was obtained from Merck Company (Merck, USA). The stock solutions of PAN/DMF were prepared by dissolving PAN in DMF at 60ºC for 12h with continuous and vigorous magnetic stirring.

2-2. Electrospinning
The PAN/DMF solutions (7.0, 9.0 and 11.0 wt.% ) were electrospun using needleless electrospinning system (Fanavaran Nano Meghyas Ltd., Co., Tehran, Iran). Needleless apparatus was comprised of a rotating drum collector made of steel, a Teflon solution vessel, two steel discs connected with wires as the spinneret and a high-voltage DC power supply connected to the collector and bottom of the solution vessel. During electrospinning, spinneret was placed in the polymer solution bath so that the solution was loaded onto its while spinneret was rotating

The selected range of the variables and the levels of the parameters are in the following based on our preliminary studies:
The selected range for polymer solution concentration was 7.0, 9.0 and11.0 wt.%.
The selected range for applied voltage was 30, 35 and 40 kV.
The selected range for spinneret to collector distance was 10, 13 and 16 cm.
Data normalization was performed using mapminmax functions based on equation (1) in the pre-processing step before ANN modeling. Mapminmax functions with the following algorithm normalized the minimum and maximum values to [-1, 1]:

Ynorm=((Ymax-Ymin)(X-Xmin))/((Xmax-Xmin) )+Ymin
Where Ymin and Ymax are -1 and 1, respectively. The x is the data which is normalized. Xmax and Xmin are the maximum and minimum values of x.
The schematic diagram of the artificial neural network model is shown in Fig.1. The training parameters of neural networks and the experimental dataset used for ANNs modeling are listed in Table 1 and 2,