Electrospun porous PLLA and poly(LLA-co-CL) fibers by phase separation

Polylactide (PLLA) and polylactide-co-poly(e-caprolactone) (poly(LLA-co-CL)) with lactide/caprolactone content ratios of 9/1 and 7/3 were successfully electrospun into porous fibers. According to a previous study, the porous structure was induced by phase separation from the rapid evaporation of solvent or the addition of nonsolvent. In this study, five types of solvents with different vapor pressures and electrical conductivities and different solubilities for LLA and CL segments were used during the electrospinning process to investigate the effect on the formation of porous poly(LLA-co-CL) fibers. SEM image analysis indicated that porous fibers were established via the change in copolymer segment content. Solvent volatility and solubility for LLA and CL segments were important factors for pore formation. The porous fibers had weaker mechanical properties compared with the nonporous fibers. Water contact angle measurements indicated that the hydrophobicity of the fiber membranes was enhanced with an increase in the BET specific surface area or porosity.