Effect of Processing on the Morphology and Structure of PLGA/PVA Fibers Produced by Coaxial Electrospinning
T. Rego, Anna Lecticia Martinez Martinez Toledo, Marcos L. Dias
Abstract
The electrospinning technique can produce multifunctional polymeric devices by forming solid fibers from polymer solutions under a high-voltage electric field. Variations such as concentric needles yield core/shell fibers. This study evaluates the effects of applied voltage (12.5–20 kV) and tip-to-collector distance (12.5–20 cm) on the morphology and thermochemical behavior of PLGA/PVA fibers made by coaxial electrospinning compared with casting-produced membranes and monolithic fibers. Optimal coaxial fibers (597 ± 90 nm diameter) were produced at 15 cm/12.5 kV, exhibiting a well-defined core/shell structure (PVA core: ~100 nm; PLGA shell: ~50 nm) confirmed by laser scanning confocal (core solution labeled with fluorescein) and TEM. FTIR and TGA demonstrated nearly complete solvent removal in electrospun samples versus ~10% solvent retention in cast films. XRD analysis indicated that cast films (PLGAff) exhibited minimal crystallinity (Xc ≈ 0.1%), while electrospun PLGA (PLGAe) showed cold crystallization and higher crystallinity (Tcc ≈ 90.6 °C; Xc ≈ 2.45%). DSC detected two different Tg (≈43.2 °C and 52.8 °C) in the coaxial fibers, confirming distinct polymer domains with interfacial interactions. These results establish precise processing/structure relationships for defect-free coaxial fibers and provide fundamental design principles for hybrid systems in controlled drug delivery and tissue engineering applications.