Unique Transitions in Morphology and Characteristics of Porous Poly(Lactic Acid) Enantiomers

This study examines unique changes in the morphology and physical properties of monolithic poly(lactic acid) (PLA) enantiomers. It is revealed for the first time that PLA monoliths containing stereocomplex (sc) crystals are successfully produced using enantiomeric poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA) using a simple phase separation process with ternary solvent (1,4-dioxane/2-butanone/water). The basic structure of the monoliths is changed drastically from needle-like to spherical morphology until reaching a PLLA/PDLA ratio to equivalence. The PLA monolith prepared from a stoichiometric amount of PLLA/PDLA has high sc crystallinity without any homochiral crystals, and it shows higher melting temperature (226 degrees C), surface area (131 m(2) g(-1)), and water contact angle (144.5 degrees) compared with those of neat PLLA (180 degrees C, 86 m(2) g(-1), and 137.5 degrees, respectively). Moreover, this sc-PLA monolith exhibits excellent resistance to several good solvents of PLLA, whereas the pristine PLLA monolith is dissolved instantly in these solvents.