Surface Segregation of Partially Fluorinated Comb-Shaped Amphiphilic Copolymer in PVDF Membrane: Experimental and Molecular Dynamic Simulation Study

Herein, we report the one-pot synthesis and molecular dynamics (MD) simulations of a partially fluorinated comb-shaped amphiphilic copolymer (PTPO) comprising short poly(2,2,3,3-tetrafluoropropyl methacrylate) (PTFPMA) and long poly(oxyethylene methacrylate) (POEM) chains for poly(vinylidene fluoride) (PVDF) membranes. PTPO exhibited a well-defined microphase-separated structure and had dipole–dipole interactions with PVDF. The hydrophilic POEM domains aligned with the surface, whereas the hydrophobic PTFPMA domains anchored within the PVDF matrix. Compared with the neat PVDF, the PVDF/PTPO membrane flux increased by up to 2300%, and the flux recovery ratio reached 95.7%, with high bovine serum albumin rejection. Furthermore, the PVDF/PTPO membranes demonstrated superior mechanical properties (>4 MPa) compared with those of the other PVDF-based ultrafiltration membranes. Posttreatments such as ethanol immersion improved the surface hydrophilicity without the leaching of PTPO. MD simulations provided insights into the interaction between the PVDF/PTPO blends and water nonsolvent and the free volume of the PVDF/PTPO membranes with varying PTPO loadings. This study suggests that the microphase separation of the comb-shaped amphiphilic PTPO can effectively improve the antifouling performance as well as water permeability of the PVDF membrane.