Unidirectionally aligned and randomly oriented electrospun nanofibrous polyacrylonitrile membranes

Abstract Polyacrylonitrile (PAN) membranes, in the formation of unidirectionally aligned and randomly oriented nanofibers, have been processed using a simple hybrid-drum collector and a dual-strip collector by electrospinning, respectively. The analysis for mechanical properties of former membranes revealed that the longitudinal stiffness (0.69 ± 0.12 GPa) and fracture strength (23.7 ± 3.2 MPa) are about two to three times higher than those of corresponding transverse counterparts. However, the longitudinal strain to rupture (5.96% ± 1.77%) is about 50% lower than transverse rupture strain. In contrast, the membranes processed by the dual-strip collector possessed uniformly porous structures with resulting nanofibers distributed randomly in all directions. Moreover, XRD patterns revealed broadened peaks at 5.249 and 3.05 A resulting in the variability in the fracture strength in view of both longitudinal and transverse properties. This finding was consistent with predictions derived from a Weibull analysis for the mechanical reliability of PAN nanofibrous membranes. It is believed that this simple electrospinning method for processing strong and stiff PAN nanofibrous membranes may have useful exploitation based on mesh-like structures for drug delivery, tissue scaffolding, and nanofiltration.