Electrospun Polymer Nanofibers and their Potentials

When the diameter of polymer fibers is shrunk from micrometers to submicrons or nanometers, two amazing properties result: – a very large surface area to volume ratio and much superior mechanical stiffness and tensile strength along the fiber. These outstanding properties make the polymer nanofibers candidate materials for many important applications (Figures 1). 

Figure 1: The efficiency of filters increases as the fiber diameter decreases.



Figure 2: Electrospun biodegradable nanofibers.

Among various processing techniques, electrospinning is the only method capable of mass producing continuous polymer nanofibers. However, the current understanding of this process and relevant parameters is still very limited. Furthermore, available nanofibers are essentially in non-woven form. Another challenge is in the control of the resulting nanofiber diameter. 

The present research focuses on processing, characterisation, and new applications of polymer nanofibers by means of the electrospinning technique. The spinability of various polymers has been studied and ways are devised to obtain uniaxially aligned nanofibers (Figure 2). The mechanical properties of nanofibers are being determined by performing a single fiber tensile test, micromechanical retrievals, and molecular simulations. Biomedical compatibility is being determined using both nanofiber mats and single nanofibers. 

A number of applications of such polymer nanofibers are being explored, including molecular filtration, junction thermocouples, and orthopedic/orthodontic biomedical devices. As for molecular filtration, one possible way to obtain only one enantiomer as pure drugs from some racemic mixture is to make use of nanofiber membranes, obtained through electrospinning with antibodies attached, to selectively transport the desired enantiomer from the racemic mixture into a receiver solution. A similar idea will lead to the development of a portable water purification apparatus. A single nanofiber coated with two metals a single nanofiber coated with two metals at different segments will create a junction, which can be made into a thermocouple to detect inflammation of coronary arteries with extremely fast response times. Such nano-thermocouples can be inserted into a cell to monitor the metabolic activities at various locations within the cell. Furthermore, multiple thermocouples can be circumferentially mounted on a catheter balloon to allow for mapping of the arterial wall temperature. Applications of polymer nanofibers in the field of orthodontics/orthopedics include archwires, brackets, bone plates and pins.

Our research team comprises Assoc Prof S Ramakrishina, Dr ZM Huang, Dr M Kotaki, Dr C T Lim, Mr YZ Zhang, and Mr R Inai.