Coaxial electrospinning of miscible PLLA-core and PDLLA-shell solutions and indirect visualisation of the core-shell fibres obtained
Core-shell fibres of semi-crystalline poly(L-lactic acid) (PLLA) (core) and amorphous poly(D,L-lactic acid) (PDLLA) (shell) were produced through the coaxial electrospinning of two miscible solutions. Due to the poor contrast between the PDLLA and PLLA, the core-shell structure of the resulting fibres could not be elucidated using TEM. An indirect visualisation method was devised consisting of a combination of SEM, selective dissolution, polarimetry and DSC. The method is evaluated here and applied in the investigation of the effect of spin solution concentration and flow rate on the morphology of the resulting fibers.