Morphology and Thermal Properties of Core-Shell PVA/PLA Ultrafine Fibers Produced by Coaxial Electrospinning

Abstract

Coaxial electrospinning process was used to produce biodegradable membranes made of coreshell\rfibers of a poly(lactic acid) (PLA) shell and a poly(vinyl alcohol) (PVA) core. Scanning electron\rmicroscopy analyses of these structures showed that the PLA shell can present certain porosity\rdepending on the process condition. FTIR-ATR and contact angle measurements also suggested\rimprisonment of the PVA core within the PLA shell. This type of structure was also confirmed by\rmeans of transmissions electron microscopy. The morphology of these fibers was dependent on\rthe flow rate of both core and shell solutions, and homogeneous and smooth surface was only attained\rwhen the flow rate of the external PLA solution was 4 times the flow rate of the internal\rPVA solution. The increase in the PLA solution flow rate increases the diameter of the core-shell\rfiber which reaches up to 1.7 μm. Nevertheless, fibers with smaller average diameter could also be\rproduced (200 nm). These core-shell fibers presented improved hydrophilicity as compared with\rmonolithic PLA fibers.