Preparation of electrospun shape memory polyurethane fibers in optimized electrospinning conditions via response surface methodology

Herein, the electrospinning method, as an effective approach, was utilized to fabricate poly (epsilon-caprolactone)-based polyurethane (PCL-based PU) fibers. PCL was synthesized by ring-opening polymerization, and characterized by proton nuclear magnetic resonance (H-1 NMR) and Fourier-transform infrared (FTIR) spectroscopies. Afterward, PU was prepared by step-growth polymerization. The effects of solution concentration and solvent type on fibers' diameter were investigated. Scanning electron microscopy (SEM) images revealed that the optimum solution was N, N-dimethylformamide(DMF): chloroform with a ratio of 60:40. In addition, results showed that bead-less nanofibers could be achieved by a concentration of 5 w/v% (polymer to solvent). Various optimum practical parameters, such as applied voltage, feeding rate, and needle-to-collector distance, were obtained and compared with the results of response surface methodology (RSM). On the other hand, the mechanical evaluations indicated that the porous structure of scaffolds caused them to possess lower mechanical properties, as well as shape fixity ratios than those of bulk samples.