Continuous Twisted Nanofiber Yarns Fabricated by Double Conjugate Electrospinning

In order to fabricate continuously twisted nanofiber yarns, double conjugate electrospinning had been developed using two pairs of oppositely charged electrospinning nozzles. The principle and process of this novel yam spinning method were analyzed, and the effect of applied voltage, nozzle distance between positive and negative, solution flow rate and funnel rotating speed on the diameters, twist level and mechanical properties of resultant PAN nanofiber yams were investigated in this paper. The results indicated that electrospun nanofibers aggregated stably and bundled continuously at the applied voltage of 18 kV, the nozzle distance of 17.5 cm between positive and negative, the overall flow rate of 3.2 ml/h and the flow ratio of 5/3 for positive and negative nozzles. The resultant nanofiber yams had favorable orientation and uniform twist distribution, and the twist level of nanofiber yams increased with the increase of the ratio of funnel rotating speed and winding speed. The diameters and mechanical properties of nanofiber yams depended on their twist level. The diameters of prepared PAN nanofiber yams ranged from 50 mu m to 200 mu m, and the strength and elongation of PAN nanofiber yams at break were 55.70 MPa and 41.31%, respectively, at the twist angle of 41.8 degrees. This method can be also used to produce multifunctional composite yarns with two or more components.