Probing the hydrophobicity of commercial reverse osmosis membranes produced by interfacial polymerization using contact angle, XPS, FTIR, FE-SEM and AFM

► AK, AG, SE and SG are commercial RO membranes with contact angles higher than 60°. ► AK, AG have rougher surfaces while SE, SG have thinner and smoother top layer. ► AK, AG exhibit peaks at 1541 cm−1 and 1609 cm−1 while SE, SG have peaks at 1730 cm−1. ► AG has lower O/N ratio than AK whereas SE has lower C/N ratio than SG. ► Advanced analysis provided insight into structures of these polyamide membranes.