Chiral PLLA particles with tunable morphology and lamellar structure for enantioselective crystallization

Poly(L-lactide) (PLLA) porous materials have become increasingly important for practical applications. However, the methods for preparing PLLA-based porous particles are quite limited. The chirality of PLLA materials remains scarcely explored even though PLLA is a well-known chiral polymer. In this paper, we establish an unprecedented, facile approach for preparing PLLA particles with lamellar structures by precipitation polymerization. By adjusting polymerization conditions (solvent and temperature), a series of PLLA particles with tunable morphology was fabricated. The resulting particles were characterized by SEM, CD, XRD, DSC, and GPC measurements. We further explored chiral resolution ability of the PLLA particles used as chiral additive to induce enantioselective crystallization. According to SEM, CD, and XRD characterizations, PLLA particles show considerable enantioselectivity and preferentially induce l-threonine to crystallize from the racemic solution. Besides, enhancing the crystallinity of PLLA particles is beneficial for improving the particles’ enantiodifferentiating ability. The present study provides a versatile platform for developing novel PLLA materials, which deserve more attention as chiral biomaterials.