Experimental investigation of aligned groove formation on the inner surface of polyacrylonitrile hollow fiber membrane

The fabrication of textured hollow fiber membrane (HFM) such as fibers with aligned grooves on the inner surface is of great interest especially for nerve regeneration applications. Grooved polyacrylonitrile (PAN) HFMs have been successfully fabricated using a dry-jet wet spinning process. Aligned grooves are formed on the HFM inner surface due to process-induced instability under selected fabrication conditions (air gap distance, polymer solution concentration, and polymer solution and nonsolvent flow rates). The influence of different fabrication conditions has been experimentally investigated to appreciate their relationship with the groove formability. It is found that HFMs with aligned grooves on the inner surface can be fabricated within an identified groove forming region, which is defined by the air gap distance, polymer solution concentration, and polymer solution and nonsolvent flow rates; and within the groove forming region, the number of grooves increases with the air gap distance from 1 to 20 cm, and it decreases with the polymer solution concentration and flow rate. The number of grooves is not sensitive to the inner nonsolvent flow rate.