Effect of flow rate on wetting and optical properties of electrospun poly(vinyl acetate) micro-fibers

In this work, extremely hydrophobic micro-fibers from polyvinyl acetate (PVAc) were obtained by changing the flow rate of the solution in electrospinning process. Surface morphologies and wettability of the fiber surfaces were strongly affected from the flow rate of the electrospinning solutions; it was found that with the increase of flow rates from 2 to 5 mL/h, the diameters of the fibers have shown an increase from 3.22 to 4.75 μm, and also water contact angle (CA) values were increased up to 146°. Equilibrium ( θ e ) and advancing ( θ a ) CA results showed us that fiber surfaces become extremely hydrophobic in the case of 4 mL/h and 5 mL/h solution flow rates and CA values were measured 148° and 161°, respectively. Increase in flow rates has changed the optical transmittance values; PVAc fibers have shown lower light transmittance and poor transparency at higher flow rates. When flow rates were increased from 2 to 5 mL/h, the transmittance values have shown a decrease from 3 to 0.25% and 2.5 to 0.25%, at 400 nm and 700 nm, respectively.