fatemeh khodkar - Chemical Engineering Faculty, Polymer Engineering Department, Tarbiat Modares University, Tehran, 14115-114, Tehran, Iran
nadereh Golshan ebrahimi - Chemical Engineering Faculty, Polymer Engineering Department, Tarbiat Modares University, Tehran, 14115-114, Tehran, Iran

In this work, the effect of viscosity ratio and flow rate ratio of solutions on coaxial electrospun fibers were investigated simultaneously. The core/shell fibers were made by 10 and 12% (w/v) polycaprolactone (PCL) in chloroform and DMF (9:1 in volume) as core solution and 8 and 12% (w/v) polyvinylalcohol (PVA) in water as shell solution. These samples were examined under three conditions (1, 1.7 and 2.5 flow rate ratio). A field emission scanning electron microscopy (FESEM) is used to evaluate the structure and morphology of the fibers. The FESEM micrographs showed the flow rate ratio is dependent on shear viscosity ratio. When the viscosity ratio is less than one, the fiber diameter decreases with increasing the flow rate ratio. While with viscosity ratio more than one, the fiber diameter enhances with increasing the flow rate ratio

Electrospinning- core/shell fiber- polycaprolactone- polyvinylalcohol