A method for preparing a hydrogel coating for a wound dressing to provide the wound dressing with non-adhesion properties without interfering with the bioactivity of the agents contained in the wound dressing. The hydrogel coating is formed by treating the substrate with O2 plasma before applying a hydrogel precursor solution onto the substrate, and then curing the hydrogel precursor onto the substrate to form the hydrogel coating on the surface of the substrate. Hydrogel coatings for a wound dressing and wound dressings having a hydrogel coating are further described.