Fiber forming processing electrospinning

As stated in the previous section, achieving control over the orientation of electrospun fibers is an important step towards many of their potential applications. However, if one considers the fact that fiber formation occurs at very high rates (several hundreds of meters of fiber per second) and that the fiber formation process coincides with a very complicated three-dimensional whipping of the polymer jet (caused by electrostatic bending instability), it becomes clear that controlling the orientation of fibers formed by electrospinning is no simple task [94]. 

Intrinsic properties of polyester, such as its molecular weight and parameters of the polymeric solution, such as concentration, viscosity, and conductivity have significant influence on the electrospinning process and the characteristics of the formed fibers [8]. The electrospinning method requires a minimum concentration of polymers for the formation of fibers. The polymer solution must have... 

The morphologieal struetme ean be slightly changed by changing the solution flow rate as shown in Figure 12. At the flow rate of 0.3 ml/h, a few of big beads were observed on the fibers. The flow rate eould affect electrospinning process. When the flow rate exceeded a critical value, the delivery rate of the solution jet to the capillary tip exceeded the rate at which the solution was removed from the tip by the electric forces. This shift in the mass-balanee resulted in sustained but rmstable jet and fibers with big beads were formed [56]. 

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