Functionalizable coaxial PLLA/PDLA nanofibers with stereocomplexes at the internal interface

摘要

Multifunctionality of electrospun polylactic acid (PLA) nonwovens was generated by the morphological design of nanofibers. Coaxial fibers with a lower number average molar mass M_n PLLA core and a higher M_n PDLA shell form PDLA-PLLA stereocrystals at the interface, induced by annealing. In tensile tests under physiological conditions, the core-shell fibers with higher crystallinity (22% compared to 11-14%) had lowerYoung's moduli E(9+1 MPa) and lower elongation at break ε_b (26±3%) than PDLA alone (E=31 ± 9 MPa, ε_b = 80 ± 5%), which can be attributed to simultaneous crystallization and relaxation effects. Gelatin incorporated in the PDLA phase was presented on the outer surface providing a biointerface putatively favorable for cell adherence. Gelatin incorporation did not influence the crystallization behavior but slightly lowered T_g (60 → 54 °C). Employing exclusively polymers established in the clinic, multifunctionality was generated by design.