Mechanical and Geometrical Characteristics of Electrospun PEO Nanofibers Using Atomic Force and Confocal Laser Scanning Microscopy

Technique of electrospinning dates back to 1934 when Anton Formhals patented first apparatus for production of artificial thread using electric field [Formhals, 1934]. In the last decade polymeric nanofibers produced with this method gained much interest due to their extraordinary properties such as big surface to volume ratio and enhanced mechanical characteristics.
Those great capabilities are resulting wide range of applications within medical, textile and energy industry. Our interest focuses mainly on medical applications such as medical textiles optimization, wound dressing management and bionanosensors for pathogens detection.
In active wound dressing, electrospun polymeric nanofibers play significant role as dressing materials promoting hemostasis phase of healing. Due to small pores of electrospun material water absorption of dressings can be advanced to 17,9-21,3% (whereas for typical dressing it’s 2,3%), which causes better wound exudates absorbance. Additionally semi-permeability of nanofibrous materials keeps the wound from drying up, allows high gas permeation and protects the wound from bacteria and contamination. Incorporation of therapeutic compounds within the co-spinning process results with multifunctional bioactive dressing, giving a promise of faster wounds healing without leaving scars [Zahedi, 2010]. Only few of polymers have been investigated in terms of electrospun bandages and their usefulness in wound healing.
Mentioned features are desired also for other use of medical textiles such as an alternative for plaster cast. Polyethylene oxide nanofibers enhanced with piezoelectric and sensing capabilities are a promise to better fractures management. However, mechanical characterization of these submicron structures remains a challenge and is not sufficiently studied and described in the literature. Aim of this research is to develop methodology and perform detailed analysis of geometrical distribution and quality of electrospun polyethylene oxide (PEO) fibres and their Young modulus using Confocal Laser Scanning Microscopy (CLSM) and Atomic Force Microscopy (AFM) respectively.
The methodology for the mechanical characterization is based on the works of Fuhrhop et al. [1], who used the nanoindentation method to calculate the Young’s modulus of the fibre. In the reference [4] Bellan et al. has used the three point method to calculate the Young’s modulus. We have used the results of [1] and [4] to compare and validate our results.