Nanofibrous patterns by direct electrospinning of nanofibers onto topographically structured non-conductive substrates

Patterning of electrospun nanofibers has recently attracted much attention for its usefulness in a wide range of applications. This paper reports on the generation of spatially defined nanofibrous patterns by direct deposition of electrospun nanofibers onto a variety of insulating substrates. It was found that topographical features of different non-conducting substrates could be readily replicated by the electrospun nanofibers of interest. To elucidate the underlying mechanism of nanofiber patterning, we have systematically studied the effects of surface topography of non-conducting substrates (in particular protrusions) on the nanofiber deposition and assembly. Results from experiments and electric field simulation indicated that under a strong electric field the insulating substrates can be polarized, which could consequently affect the distribution of the original electric field. For particular non-conductive substrates with small mesh sizes or sufficient thickness, surface topography of the dielectric substrate may play a key role in determining the deposition and the arrangement of electrospun fibers. In addition, parameters that could influence the fineness of nanofibrous patterns have also been investigated. This contribution is believed to warrant further scientific understanding of the patterning mechanism of electrospun nanofibers, and to allow for design of specific and complex non-conductive substrate collectors for easy generation of patterned nanofibrous architectures, applicable in a variety of areas such as tissue engineering scaffolds and optoelectronic displays.