In a typical electrospinning process, a charged polymer melt of solution is extruded toward a grounded collector plate. At sufficiently high electric fields, the polymer stream is whipped about, leading to the formation of a nonwoven mat of submicrometer-diameter fibers.
Li et al. modified the basic setup by using a split collector plate composed of two parallel conducting strips, separated by a gap of variable width. The electric field that was generated led to the formation of large area arrays of oriented parallel fibers, which were easily transferred to a substrate for further processing. The authors were able to create fibers of a variety of polymers, TiO2/polymer composites, Sb- doped SnO2, and a number of other ceramics.
Ko et al. electrospun solutions of either polylactic acid (PLA) or polyacrylonitrile (PAN), which had been mixed with single-walled carbon nanotubes (SWNTs), to produce composite fibers and yarns. In the PLA fibers, the SWNTs formed spherical agglomerates, but in the PAN fibers, the SWNTs were uniformly distributed and were oriented parallel to the fiber direction after spinning. The fiber mats showed improved mechanical properties, and it is believed that they can be heat-treated to form a carbon/SWNT composite. -- MSL
Nano Lett. 10.1021/nl0344256 (2003); Adv. Mater. 15, 1161 (2003).
