Physical properties of the electros

Physical properties of the electrospun PVDF nanofiber mat were improved by the thermal treatment. Modulus, tensile strength, and elongation at break of the thermally treated mat were much higher than those of the untreated mat. The improved physical properties were explained with the in- creased crystallinity, mat shrinkage and nanofiber thickening. The electrospun PVDF nanofiber mat was treated with ethy- lene plasma to introduce PE layer on the mat surface to use as a separator with a shutter. Pores on the ethylene plasma- treated PVDF mat are clogged by melting PE molecules on the mat surface.