Controlled Swelling-Assisted Adsorption of Pluronic F-127 on Compact Poly(vinylidene fluoride) Surfaces

Physical adsorption of functional modifiers onto compact polymer surfaces may be influenced by the space available for modifier accommodation. Here, we report a controlled swelling-assisted strategy for enhancing Pluronic F-127 adsorption on compact poly(vinylidene fluoride) surfaces. Aqueous N,N-dimethylformamide (DMF) solutions served as composition-tunable swelling agents. Increasing DMF concentration was accompanied by increases in the mass-based swelling degree and F-127-associated surface enrichment. The surface oxygen content increased from approximately 4.9 atom % for the 0 vol % DMF sample to 18.2 atom % for the 50 vol % DMF sample, while the contact-angle-based wettability persistence index after 6 h of shaking water exposure increased from 6.2% to 54.0%. After deswelling, no pronounced deterioration was detected in the examined near-surface cross-sectional morphology, tensile strength, or XRD-estimated crystallinity. Compared with the 0 vol % DMF reference, films prepared in DMF-containing solutions generally showed greater wettability, lower hemolysis ratios, and fewer visible surface-associated platelets and red blood cells. These findings support swelling-assisted adsorption as a tunable route for modifying compact polymer interfaces.