High Precision Deposition Electrospinning of nanofibers and nanofiber nonwovens

Electrospinning is known to produce nanofiber nonwovens with lateral dimensions in 10 cm up to the meter range meeting thus requirements characteristic of filter, textile or even tissue engineering applications. For particular applications other types of deposition pattern are of benefit (i) in which the deposition area is strongly limited in the lateral dimension, (ii) in which a linear deposition path is oriented along a specified direction or (iii) in which the nonwovens are deposited following a predesigned pattern. This paper reports experimental results for the High Precision Deposition Electrospinning (HPDE) approach introduced by us earlier. It is based on a syringe type die-counter electrode set-up used for conventional continuous electrospinning, the key feature being a reduction of the distance between the spinning die and the substrate from the conventional value of 10-50 cm down to the millimeter and below mm range in order to suppress the onset of bending instabilities and the corresponding spread of the deposition area. The architecture of the nonwovens is controlled in this case by buckling processes and deflections of the jet by transiently charged nanofibers on the substrate. A second important feature of the set-up is a counter electrode/substrate which can be subjected to precise motions in the deposition plane. Based on a careful optimization of the spinning parameters and a tight online control of the spinning process a deposition of individual nanofibers or nonwovens is achieved which meets all deposition requirements specified above. This opens the route towards novel applications among others in areas relying on specific surface architectures such as sensorics, microfluidics and possibly also surfaces of implants.