Tailoring the Morphology and Properties of Stereocomplex‐Type Porous Poly(Lactic Acid) Materials via Poly(ε‐Caprolactone) Incorporation

ABSTRACT Porous poly(lactic acid) (PLA) materials with tailorable pore architectures are highly desirable for tissue engineering and separation applications. Here, poly(ε‐caprolactone) (PCL), a ductile and semicrystalline polyester, was introduced as a third component into the poly(L‐lactic acid)/poly(D‐lactic acid) (PLLA/PDLA)/1,4‐dioxane system, and binary PLLA/PCL (LC) and ternary PLLA/PDLA/PCL (LDC) porous materials were prepared via thermally induced phase separation (TIPS). The structure formation pathway depended decisively on PDLA. In its absence, solvent crystallization dominated, and liquid–liquid phase separation between PLLA and PCL disrupted the regular channel‐like pores. In its presence, stereocomplex (SC) crystallization during isothermal holding built a particulate framework that directed a worm‐like nanoporous structure, with PCL accumulating around the SC crystallites. PCL promoted the engagement of enantiomeric chains in SC formation but coarsened the pore structure, decreasing the porosity from 82% to 73% and increasing the median pore diameter from 3.2 to 8.9 μm. The LDC materials also exhibited higher thermal stability than their LC counterparts. These findings clarify the crystallization–phase separation interplay in multicomponent TIPS systems and guide the rational design of porous PLA materials.