Strengthened corrosion control of poly (lactic acid) (PLA) and poly (ε-caprolactone) (PCL) polymer-coated magnesium by imbedded hydrophobic stearic acid (SA) thin layer

•Stearic acid film imbedded in poly (lactic acid) & poly(ε-caprolactone) coated Mg.•Significantly smaller corrosion current density was obtained.•More important, manifestly slower and stable degradation manner was accomplished.•This is credited with its kinetic and hydrophobic contributions of imbedded layer.