Electrospinning is a process for producing nano- and micro-fibers from a polymer solution. As the name implies, electrospinning uses electrostatic forces to draw out thin fibers from a polymer solution, rather than mechanical forces which are used in other fiber producing methods, i.e. meltblowing.
Cellevate uses a patented electrospinning technique refined at Lund University, Sweden. The process combines concepts of centrifugal spinning with electrospinning. A polymer solution is pumped and deposited centrally onto a quickly rotating spinning disc. Due to the centrifugal forces the polymer solution is transported radial towards the rim (perimeter) of the rotating disc where the surface tension is broken by the centrifugal force and a multitude of liquid jets are ejected. An electric field is applied between the disc and the collector electrode by a high voltage supply. The electric field is directing the liquid jets towards the collector and helps to stretch the jets to very fine dimensions under simultaneous evaporation of the solvent leaving a dry nano-fibrous coating on the substrate passing the collector plate.
It should be noted that the process is insensitive to ambient conditions like temperature and humidity. This is a clear advantage compared to needle-based or needleless processes which sometimes produce vastly different results depending on such parameters. The use of rotating discs during fiber production also adds additional controllable process parameters, the rotational speed of the discs, resulting in increased opportunities to fine tune the characteristics of the produced fibers. The rotating discs also lower the dispersion of fiber diameters significantly, which is of great importance in many biotech and electrical applications.
Nanofibers, usually defined as fibers with diameters on the nanoscale (1 - 1000 nm), have during the last decade received great attention both in the academia and industry. The large surface to volume ratio generates several interesting properties which are desireable for a great variety of applications. A few of these are listed below.