Morphological characterization of electrospun nano-fibrous membranes of biodegradable poly(L-lactide) and poly(lactide-co-glycolide)

Hydrophobic biodegradable polyesters, poly(L-lactide) (PLLA) and poly(lactide-co-glycolide) (PLGA), were electrospun on different types of collectors to induce morphological changes in the nanofibrous membrane. On the metal collector smooth nonwoven membranes were obtained for both PLLA and PLGA, while on the water reservoir the surface of the membranes became rough due to shrinkage and slow charge dissipation. When NaCl was added to water to enhance the conductivity, the roughness of the membrane surface was changed, yet the shrinkage remained relatively unchanged. The crystallization of PLLA electospun material on the metal plate was suppressed because of the rapid solvent evaporation, however, upon annealing above the glass transition temperature for 24 hr the PLLA membrane became crystallized. When electrospun on the water reservoir, the PLLA membrane remained amorphous. Crystalline PLLA was obtained by electrospinning on the methanol reservoir due to the swelling of nanofibers by methanol.