synthesized as a mimetic of the natural musseladhesiveprotein (MAP). The obtained copolymer in a phosphate buffer solution (pH = 8.0) formed a hydrogel within 2 h under air, whereas gelation did not proceed under argon atmosphere. We confirmed that the cross‐linking reaction of the synthesized MAP mimetic copolymer was triggered by aerobic oxidation of catechol moieties to form an adhesive hydrogel. Two