Multiphysics modeling and experimental verification of solidification point of melt-electrospun jet

Melt electrospinning has been recognized as an attractive solvent-free process over the past few decades to alleviate the solvent-related problems generated by traditional electrospinning techniques. In melt spinning, the drawing process of molten jets occurs in the liquid phase region before the phase transformation. Besides, the insufficient chain flow in the solid phase results in the non-stretchable properties of the jet in this state. This analysis predicted the phase transition displacement in the polymer jet during the melting process using a two-dimensional non-isothermal flow model integrated with an electric field. High-speed photography was employed to collect photographs of the phase transition point of the jet to verify the simulation results. Additionally, we evaluated the diameters of fibers manufactured with various phase transition displacements induced by different applied voltages. The findings of the experiments reveal that as the applied voltage is enhanced, the freezing point of the jet becomes gradually closer to the nozzle side, and the solidification length significantly reduces, resulting in smaller fiber diameter. Moreover, the results mentioned above are consistent with the law predicted by the simulation, proving the feasibility and accuracy of the model. This work will provide potential guidance for the study of nanoscale melt fibers from the perspective of fluid phase transformation.