Although it sounds simple in principle, in reality the spinning process is quite complicated. Numerous parameters influence the process, including the concentration of the solution, the dielectric constant of the solvent, the strength and shape of the electric field and environmental conditions such as the relative humidity of the air. It demands experience and skill from the experimenter to adjust the process parameters so that fibers form and not just droplets, and on top of this for every new material a new set of optimal parameters must be established.
Filter systems for medicinal applications
To date the Empa researchers have been able to successfully spin a number of polymers and other materials including polyamide, polyethylene oxide, polyvinyl pyrrolidone and wool protein in combination with polymers. The latter material can be used as a biocompatible substrate on which to grow cells.
The current scientific task is to establish the optimal layout and operation of the apparatus in order to be able to spin fibers with complete control. A further aim is the manufacture of filters for medicinal applications, and for this purpose filter materials are given an additional coating of nano fibers. The electrospinning process is particularly suitable for this application since it takes place at room temperature. Heat -sensitive active agents can thus be directly mixed into the fibers that are then coated onto the filter materials.