Production of Monolayer and Bilayer Nanofibers via Electrospinning Process

Electrospinning is one of the processes that allows efficiently producing nanofibers with very small diameters. It shows great potentialities for effective upscaling, especially in the biomedical field, thanks to its operational simplicity. In the current research, electrospun membranes made of Polycaprolactone (PCL) and Gelatin (GN) have been produced and analyzed. In literature, comparisons between uniaxial electrospinning (blending the two polymers) and coaxial electrospinning (forming bilayer nanofibers) are reported mainly to highlight the differences of surface properties between the systems (e. g. wettability, drug delivery, etc.). In the current research, the differences in mechanical and structural properties depending on the type of process (coaxial or uniaxial electrospinning) are analyzed. In the coaxial configuration, since GN and PCL are spun by two different polymeric solutions, the interaction between the two polymers is less intimate than the one in uniaxial configuration. For this reason, coaxial electrospun membranes show mechanical properties intermediate between GN and PCL alone. Indeed, the strain at break is between 10% and 25% for coaxial systems, whereas is 3% for GN alone and 79% for PCL. In blend electrospun membranes, very different mechanical properties are reported. The strain at break increases from 79% of the PCL alone to 349% for PCL/GN blend, probably because the interaction between GN and PCL affects the crystalline structure of PCL, leading to form smaller crystals. In this way, these materials can be considered for new types of applications in which very high strainability is required. Moreover, it is proved that it is possible to significantly vary the properties of the nanofibrous membrane by choosing adequately the process configuration.