(413e) Solvent Evaporation and Drying of Nanofibers in an Electrospinning Process

Electrospinning is a promising technology to produce nano sized fibers for diverse applications including biomedicals, composites, protective coatings, sensors, energy storage, membranes and filters. Electrospun fibers are produced by applying high voltage at the spinning tip where the polymer solution is fed and collecting almost dry polymer fibers on the grounded collector surface. Typically polymer solutions are used in between 2-20% polymer concentration in an  electrospinning process depending on their rheological and viscoelastic properties. Solvent evaporation process during the electrospinning of polymer solutions is governed by the  convective diffusion of solvent vapor from fiber surface into atmospshere far from the fibre. At least three other phenomena can also affect the evaporation process: i) the surface curvature affects the vapor pressure (Kelvin effect); ii) the charge affects the vapor pressure (Thomson effect); iii) Slip flow due to non-continuos gasous medium (Knudsen correction). The contributions of those factors during the electrospinning of PEO/water solutions will be presented.