Polysulfone membranes strongly hydrophobic from one side and hydrophilic from the other side are reported. The membranes demonstrate diode-like water permeability. The membranes are obtained by the breath figures self-assembly with micro-scaled stainless steel gauzes used as carrying supports. Hydrophilicity is achieved by exposure of one side of the membrane to UV light. Hydrophobicity of the non-treated side of membranes is strengthened by the Cassie–Baxter wetting.