Nanoporous nanocomposite membranes via hybrid twin-screw extrusion—multijet electrospinning

Abstract

Non-woven nanoporous membranes of poly(caprolactone), PCL, incorporated with multi-walled carbon nanotubes, CNTs, could be fabricated via an industrially-scalable hybrid twin screw extrusion and electrospinning process. The utilization of a spinneret with multiple nozzles allowed the increase of the flow rate beyond what is possible with conventional electrospinning using a single nozzle, albeit at the expense of difficulties in the control of the thickness distributions of the nanofibrous membranes. The thickness and orientation distributions and the resulting mechanical properties of the membranes could be modified via changes in voltage, angular velocity of the collector mandrel and separation distance of the collector from the spinneret. The increases in crystallinity due to the presence of the CNTs and the preferential alignment of the nanofibers via rotation of the collecting mandrel led to increases in the tensile properties of the nanoporous membranes. The use of poly(ethylene oxide), PEO, together with PCL, followed by the dissolution of the PEO, rendered the nanofibers themselves nanoporous with typical surface porosity values of around 50% and pore sizes of about 220 nm. The demonstrated versatility of the hybrid twin screw extrusion and electrospinning process and the manipulation of mesh dimensions and properties are indicative of the applicability of the hybrid process for fabrication of nanoporous membranes for myriad diverse industrial applications ranging from water treatment to tissue engineering applications.

Mass-Production and Characterizations of Polyvinyl Alcohol/Sodium Alginate/Graphene Porous Nanofiber Membranes Using Needleless Dynamic Linear Electrospinning

“…Similarly, using a dynamic rotating cylinder as the spinning nozzle produces a great range in the diameters of nanofibers [31,32]. In addition, when using PVA in the electrospinning materials, cone metallic coil electrospinning has a yield of 2.5 g/h, which is thirteen times higher than conventional single needle electrospinning (less than 0.3 g/h) [33,34,35,36] and the nanofibers have a lower diameter than needle electrospinning. For example, Golafshan et al used needle electrospinning to form Gr-AP nanofiber stents that were suitable for nerve engineering and the nanofibers had a diameter above 300 nm.…”

Porous Fiber Processing and Manufacturing for Energy Storage Applications

“…There are different approaches to increasing the specific surface area further by increasing porosity, refining the structures, and implementing both. For example, electrospinning [23], extrusion spinning [24], melt processing [25], thermally controlled reduction [26,27], templated assisted fabrication [28,29] and multiphase reactions [30] have been found very effective on tuning the structures and improving the performances. Through some of these techniques, increased specific area [31] and desired interface structures [32] have been obtained.…”