Amphiphilic star copolymers with heterografted arms conferring durable antibiofouling property to flexible poly(vinyl chloride)

Flexible plasticized poly(vinyl chloride) (PPVC) is widely used in medical devices; however, achieving persistent antibiofouling functionality after significant mechanical deformation and long-term water exposure remains a critical challenge. In this work, we introduce amphiphilic heterografted multi-arm star copolymers, polyethylenimine (PEI) cores functionalized with polyethylene glycol (PEG) and poly(ε-caprolactone) (PCL) arms (denoted as PEI-g-PEG-PCLs), as multifunctional additives for modifying PPVC. Dynamic light scattering (DLS) and optical transmittance measurements confirmed the formation of PEI-g-PEG-PCL micelles within the PPVC matrix. The incorporation of PEI-g-PEG-PCLs improved not only the mechanical and thermal properties of PPVC but also its surface hydrophilicity. The resulting composites demonstrated exceptional resistance to biofouling, reducing protein adsorption by 96.2–97.3 % for bovine serum albumin and 98.0–99.8 % for lysozyme, and lowering bacterial adhesion rates to 11 % for Escherichia coli and 19 % for Staphylococcus aureus. Furthermore, platelet adhesion and hemolysis assays confirmed the biocompatibility of the PEI-g-PEG-PCL/PPVC composites. Notably, even after undergoing three cycles of 50 % strain, the optimal PEI-g-PEG-PCL/PPVC composite retained over 91 % of its initial anti-protein fouling performance. Long-term immersion in physiological conditions (28 days) further demonstrated its durability, with more than 92 % of the original antifouling efficacy maintained. The multi-arm star topology accompanied with the long PCL arm is proposed to resolve the “entanglement–migration paradox” commonly encountered in linear or less branched polymer additives. This study presents a molecular engineering strategy for developing durable antibiofouling polymers capable of withstanding both mechanical stress and prolonged aqueous exposure in medical applications.