PurposeThe purpose of this study is to develop and characterize high-performance, biodegradable polylactic acid (PLA)-based materials for advanced applications that demand increased flexibility and shape memory capabilities. By introducing triethyl citrate (TEC) as a plasticizer and leveraging multimaterial three-dimensional printing configurations, this research aimed to mitigate PLA's inherent brittleness and expand its functional range. Additionally, this work sought to optimize design parameters - such as infill orientation and core-shell distribution - to maximize mechanical strength, fracture toughness and shape recovery. Ultimately, this study aspired to broaden PLA's applicability in fields like biomedical devices, packaging and engineered components.Design/methodology/approachThis study used fused deposition modeling to fabricate single-material and multimaterial (core-shell) samples using PLA blended with TEC at varying concentrations (0-20 Wt%). Filaments were first compounded and then extruded into 1.75 mm diameter feedstocks. Mechanical properties were evaluated through tensile, flexural and impact tests, while shape memory behavior was quantified by bending-deformation and recovery experiments in heated water. Morphological analyses examined void formation and fracture surfaces via field emission scanning electron microscopy. Thermal transitions and melt flow indices were also characterized to elucidate the influence of plasticizer content.FindingsThe results of this study demonstrated that adding 20 Wt% TEC significantly enhanced elongation at break up to 174% compared to neat PLA with an elongation at break close to 2%. Plasticizer lowered the glass transition temperature from 62 degrees C of neat PLA to around 30 degrees C. Shape memory recovery rate above 80% in core-shell configurations was obtained, while neat PLA exhibited recovery rates around 60%. Multimaterial samples featuring soft cores and rigid shells exhibited balanced stiffness, superior impact energy absorption and more efficient shape recovery than homogeneous counterparts. Improved melt flow indices facilitated better layer adhesion, reducing voids and increasing overall part integrity. These findings underline the potential of combining plasticized PLA and careful material distribution in additive manufacturing applications.Originality/valueThis work provides a novel demonstration of how tailored plasticization and multimaterial three-dimensional printing can collectively expand the utility of PLA, bridging the gap between traditional rigidity and the demand for flexible, shape memory-enabled structures. By systematically studying both single-material and core-shell specimens, this research offers key insights into harnessing polymer chain mobility while preserving mechanical strength. In contrast to prior efforts focusing on either plasticization or complex geometries alone, this integrated approach presents a versatile design strategy that can be applied to a wide spectrum of engineering and biomedical solutions.