fibers are of interest for a broad range of applications in areas such as sensor or filter technologies not only due to their enhanced surface to volume or surface to weight ratio. Specific surface topologies can be used to control wetting processes or the adsorption behavior. So far we are not able to describe the structure formation leading to such highly structured fibers in detail. This is the goal of current investigations.
Experimental
PLLA was obtained from BΓΆhringer Ingelheim (M n = 150 000 g/mol, M w /M n = 2), PC (Typ 2800) from Bayer. Polyvinylcarbazole was purchased from Aldrich (M w = 1 100 000 g/mol, specification by the manufacturer). All polymers were used without further purification. Dichloromethane was distilled before using. The electrospinning set-up used here has been described previously [6,7]. The polymer solution, stored within a reservoir, was pumped through a metal capillary connected with a voltage supply using a peristaltic pump. The circular orifice of the capillary had a diameter of 500 lm. A circularshaped counter electrode with a diameter of 18 cm was located below the reservoir, so that a vertical arrangement of the electrodes resulted. Fibers were collected on selected substrates, e.g., glass slides, placed on top of the counter electrode. The distance between the tip of the capillary and the counter electrode was typically of the order of 20 cm, the applied voltages were in the range from 35 kV to 45 kV.