Question

5. (15 pts) Electrostatic fiber spinning or Electrospinning is widely used for fabricating nano fiber scaffolds of polymers mimicking ECM in tissue engineering applications.

a. Explain the principle of electrospinning for producing fine nanodiameter fibers. How various process and polymer solution parameters affect the fiber-size or diameter .

b. What are the difficulties and concerns in nano spinning collagen proteins by electrospinning?

c. Explain the micro-structural changes in poly(lactide-co-caprolactone), PLCL, due to electrospinning (Answer with the help of a search in literature and differential scanning calorimetry (DSC) and XRD)

Answer 1

Electrostatic fiber spinning is a fiber production methodwhich uses electricforce to draw charged threads of polymer solutions or polymer melts up to fiber diameters in the order of some hundred nanometers.When a sufficiently high voltage is applied to a liquid droplet, the body of the liquid becomes charged, and electrostatic repulsioncounteracts the surface tension and the droplet is stretched; at a critical point a stream of liquid erupts from the surface. This point of eruption is known as the Taylor cone.

The problem associated with this process is the formation of a yarn in an electrostatic field, as follows: Charging of the fibers, and hence their behavior in the spinning zone, is dependent upon air humidity. ... The charge on each fiber, and hence its movement, is dependent upon its mass.