Mussel-inspired surface modification has received significant interest in recent years because of its simplicity and versatility. The deposition systems are still mainly limited to molecules with catechol chemical structures. In this paper, we report a novel deposition system based on a monophenol, vanillic acid (4-hydroxy-3-methoxybenzoic acid), to fabricate metal-phenolic network coatings on various substrates. The results of the water contact angle and zeta potential reveal that the modified polypropylene microfiltration membrane is underwater superhydrophobic and positively charged, showing applications in oil/water separation and dye removal. Furthermore, the single-face modified Janus membrane is promising in switchable oil/water separation. The results demonstrate a novel example of the metal-monophenolic deposition system, which expands the toolbox of surface coatings and facilitates the understanding of the deposition of phenols.