LAUSR

Biocompatible Janus composite membrane with double self‐repairing ability is constructed on the surface of magnesium, using paeonol‐doped poly(ε‐caprolactone) (P@PCL) as a hydrophobic layer and imide‐bond‐based chitosan hydrogel (PGD) as a hydrophilic layer. A copper mesh is used as the base to indirectly study this specific ability of the as‐prepared Janus membrane. The water contact angle of the Janus copper mesh‐P@PCL‐PGD with the hydrophobic layer at the bottom and the hydrophilic layer at the top is 65°, and its water retention height reached 5.1 cm, showing the strongest prevention capacity of water infiltration. Further, the damage of the hydrophobic layer is repaired by the corrosion inhibitor and the magnesium ion complex membrane; the hydrophilic layer is healed by the quick response of the imine bond in the gel to the pH change. Among all samples, the weight loss rate of Mg‐P@PCL‐PGD is found to be the smallest—only 1.19% after 12 d and 5.20% after 21 d. In short, effective protection of magnesium is achieved which is conducive to cell adhesion and proliferation, through systematically summarizing the synergy between Janus membrane and dual self‐repair. The related results are distinctive and will open up new research directions for corrosion protection of metals.