Progress in preparing electrospun Janus fibers and their applications

Despite being an important technology, side-by-side electrospinning has received less attention than uniaxial and coaxial electrospinning. Janus fibers prepared by electrospinning are an important platform in exploring different applications. In this review, different electrospinning processes, such as side-by-side, conjugate, and in combination with electrospraying, are introduced with their advantages and disadvantages. In side-by-side electrospinning, diverse designs of side-by-side spinnerets are described. Influences of different parameters on fiber morphology and inner structure and their unique superiorities of Janus structure are highlighted. Recent works on Janus fibers, including their fabrication and applications, are summarized for reflecting the advantages of Janus structure from monolithic and core-shell structures. With these advantages, materials with improved performance could be efficiently designed.