Investigation of Needle Tip Geometry on Orientation, Fiber Morphology and Mechanical Properties of E-Spun Nanofiber

摘要

Electrospinning is the most convenient method to fabricate continuous carbon nanofiber (CNF) in the form of yarn or tow. Traditional electrospinning uses a single needle with blunt tip, however, there are many hurdles in producing continuous yarns due to a highly localized electrical field, unstable Taylor cone, discontinuous jet flow, and non-uniform fibers.In this study, we investigate three different tip geometry systems such as needle with a blunt tip, a needle with a flash tip, and protruded needle tip. A 2D finite element analysis (FEA) is employed to investigate the electric field distribution for different needle tip conditions. Electrospun (E-spun) nanofibers are fabricated from 10% polyacrylonitrile (PAN) in N, N-dimethylformamide (DMF) solution using a rotating disk collector. The alignment of nanofibers within the yarn, diameter distribution, and fiber uniformity are investigated with various needle tip configurations while keeping all the other electrospinning parameters constant. The diameter distribution and alignment are investigated by scanning electron microscope (SEM). It has been reported that about 10% reduction in fiber diameters, as well as a uniform fiber with better alignment, are observed with protruded tip configuration compared to blunt tip configuration as a result of more uniform electric field distribution near the electrode.