Importance of viscosity parameters in electrospinning: Of monolithic and core-shell fibers

► To produce uniform beadless fibers, the concentration of the polymer solution must be above entanglement concentration (Ce). ► For co-electrospinning, the ηcore/ηshell must be above the threshold value for stable co-electrospinning. ► Addition of surfactant reduces the threshold ηcore/ηshell ratio.