The present invention provides a novel zwitterionic hydrogel. The zwitterionic hydrogel is polymerized from a monomer and a cross linking agent, wherein the monomer is synthesized from vinylpyridine or its derivatives and a alkyl sultone. The concentration of the monomer in the polymerization ranges from 10 to 50weight percentage. Secondly, the novel zwitterionic hydrogel apply for preventing effect of antibiofouling from decay.本發明提供一種雙離子型水膠，該雙離子型水膠是由乙烯吡啶及其衍生物和烷基磺內酯反應所形成的單體和一交聯劑進行聚合反應所構成，上述之單體在該聚合反應中的濃度是10~50wt.%。其次，本發明也揭露該雙離子型水膠應用於防止材料的抗生物分子沾黏效果衰變的用途。
