Here we demonstrated that high-content nitrogen endowed polyaniline (PANI) and polypyrrole (PPy) have not only a doping–dedoping ability but also an inherent hydrophilic property. Combining their rigid chain structures, rough surfaces can be easily achieved by uniformly and firmly coating PANI and PPy onto the surfaces of stainless steel meshes via a simple modified dilute polymerization. Compared to the pristine meshes, the modified meshes become hydrophilic in air and superoleophobic underwater, and maintain stability in various harsh conditions. Taking advantage of this unique wetting feature, PANI and PPy coated meshes were used to separate mixtures of oil and water efficiently.