Antibacterial PVDF flat sheet membranes are produced with the directly incorporation of novel synthesized N-halamine copolymers having high chlorine loading capacity and compatible with the base polymer. FTIR and H-1 NMR analysis are applied to the synthesized polymers and the presence of the polymers in the produce membrane structures are determined with FTIR and XPS analysis. To get information about phase separation behavior of the membrane solutions, ternary phase diagrams of the synthesized copolymers, PVDF, and their mixed solutions are prepared. The effect of synthesized polymers on membrane pore formation is revealed with ternary phase diagrams, water flux performance, BSA rejection performance, and SEM images of the produced membranes. Two different biocidal tests are applied to the membranes to determine the effectiveness of the membrane surfaces against biofilm formation, the speed of antibacterial efficiency and the duration of the biocidal activity of the membranes. The tests results show that only a small amount of copolymer incorporation into PVDF membranes solutions enables to production of antibacterial membranes with a long-term and rapid efficacy against S. aureus and E. coli bacteria.