Electrospinning of nanofibers

The electrospinning technique of polymer nanofibers- Equipments, Factors affecting spinning, Applications.

1. ELECTROSPINNING OF NANOFIBERS Presented By, Vishal K. P.

2. INTRODUCTION Nanofiber is any fiber with dimensions within the nano range(i.e., < 100nm) Nanofibers are created by a process called Electrospinning Main advantage of nanofiber : High surface to volume ratio Electrospinning uses an electrical charge to draw very fine (typically on the micro or nano scale) fibres from a liquid

3. ELECTROSPINNING Electrospinning  is a fiber production method which uses electric force to draw charged threads of polymer solutions or polymer melts up to fiber diameters in the order of some hundred nanometers. Strong mutual electrical repulsive forces overcome weaker forces of surface tension in the charged polymer liquid. Principle:

4. ELECTROSPINNING SETUP A high voltage power supply ( between 10 and 30kV) A polymer reservoir that can maintain a constant flow rate of solution A conductive needle as polymer source connected to the high voltage power supply A conductive collector( Plate, drum, etc.)

5. PROCESS A polymer is dissolved in a suitable solvent Polymer solution is filled in the capillary reservoir. An electrostatic potential is applied between a spinneret and a collector. The droplet is held by its own surface tension at the spinneret tip. When the electric field reaches a critical value, the repulsive electrical forces overcomes the fluid surface tension. The droplet becomes unstable, and a liquid jet is ejected:- Taylor Cone

6. The distribution of charge in the fiber changes as the fiber dries out during eruption:

7. PARAMETERS Molecular Weight, Molecular-Weight Distribution and Architecture (branched, linear etc.) of the polymer Solution properties (viscosity, conductivity & and surface tension) Electric potential, Flow rate & Concentration Distance between the capillary and collection screen Ambient parameters (temperature, humidity and air velocity in the chamber) Motion of target screen (collector)

8. ADVANTAGES High surface to volume ratio Very high porosity Enhanced physico -mechanical properties Manipulation of the solution and process parameters can be easily done to get the desired fiber morphology and mechanical strength

9. CHARACTERIZATIONS Geometric ( fiber diameter, diameter distribution , fiber orientation, and fiber morphology): SEM, TEM, AFM Chemical (Molecular structure): FTIR, NMR Mechanical (Mechanical properties): nanoindentation , bending tests, resonance frequency measurements, and microscale tension tests.

10. APPLICATIONS Sensors Wound dressing Batteries Fuel cells Solar cells Textiles Reinforcing fillers Scaffolds Drug delivery systems Water filtration membranes

11. Advantageous applications Ultrafiltration of water: High efficiency, Low fouling, High flux Drug delivery: Superior adhesiveness to biological surfaces Tissue engineering: 3D nanofibrous scaffolds

12. REFERENCES: Shaohua Jiang, Yiming Chen, et. al; Electrospun nanofiber reinforced composites: a review; Journal of Polymer Chemistry Nanomaterials Handbook; Yuri Gogotsi-2006

13. THANK YOU