After obtaining a transparent solution, they were loaded into the 5ml syringe and placed into the electrospinning device. The electrospinning device used in this study was a homemade device inside a nonconductive enclosure made by Plexiglass including an injection pump (Ascor Single-syringe pump AP14, Poland), a cylindrical aluminum collector (100 mm in diameter) and a high voltage power supply (Gamma High Voltage, United States). The speed of injection, the distance between the needle and the collector and the applied voltage were optimized for PBS-DLS (70-30) and the same parameters were applied for the rest of the copolymers. The collected fibers were characterized using SEM (TM4000+, Hitachi high-technology corporation, Tokyo, Japan)