Neat poly(vinylidene fluoride) (PVDF) ultrafiltration (UF) membranes exhibit poor water permeance and surface hydrophobicity, resulting in poor antifouling properties. Herein, we report the synthesis of a fluorine-containing amphiphilic graft copolymer, poly(2,2,2-trifluoroethyl methacrylate)-g-poly(ethylene glycol) behenyl ether methacrylate (PTFEMA-g-PEGBEM), hereafter referred to as PTF, and its effect on the structure, morphology, and properties of PVDF membranes. The PTF graft copolymer formed a self-assembled nanostructure with a size of 7–8 nm, benefiting from its amphiphilic nature and microphase separation ability. During the nonsolvent-induced phase separation (NIPS) process, the hydrophilic PEGBEM chains were preferentially oriented towards the membrane surface, whereas the superhydrophobic PTFEMA chains were confined in the hydrophobic PVDF matrix. The PTF graft copolymer not only increased the pore size and porosity but also significantly improved the surface hydrophilicity, flux recovery ratio (FRR), and antifouling properties of the membrane. The membrane performance was optimal at 5 wt.% PTF loading, with a water permeance of 45 L m⁻² h⁻¹ bar⁻¹, a BSA rejection of 98.6%, and an FRR of 83.0%, which were much greater than those of the neat PVDF membrane. Notably, the tensile strength of the membrane reached 6.34 MPa, which indicated much better mechanical properties than those reported in the literature. These results highlight the effectiveness of surface modification via the rational design of polymer additives and the precise adjustment of the components for preparing membranes with high performance and excellent mechanical properties.

Amphiphilic additives are commonly incorporated into hydrophobic poly(vinylidene fluoride) (PVDF) membranes to enhance water permeability and fouling resistance. Although a limited number of studies have reported additive migration to the membrane surface in nonsolvent-induced phase separation (NIPS) systems, simulation-based mechanistic investigations for thermally induced phase separation (TIPS) remain scarce, particularly for TIPS-derived membrane systems. In this study, amphiphilic comb copolymers, poly(2,2,2-trifluoroethyl methacrylate)-co-poly(ethylene glycol) methyl ether methacrylate (PTFEMA-co-POEM) (PTFO), were synthesized and employed to elucidate additive migration during TIPS membrane formation. A multiscale simulation framework combining density functional theory (DFT) calculations and molecular dynamics (MD) simulations was integrated with experimental characterization to model temperature-driven phase separation and subsequent solvent exchange processes. The simulations revealed weaker interactions between PTFO and the diluent compared to PVDF–diluent pairs, leading to enhanced mobility and preferential interfacial localization of PTFO along membrane surfaces and pore walls during cooling and washing. Experimental results confirmed improved surface hydrophilicity with increasing PTFO content while maintaining comparable pore structure and overall membrane morphology. These findings provide mechanistic insight into additive redistribution during TIPS membrane fabrication. More broadly, the results demonstrate that controlled interfacial migration of amphiphilic copolymers enables effective surface hydrophilization without compromising membrane structure, providing a rational strategy for designing functional additives in high-performance TIPS-derived membranes.