A novel liquid-infused, patterned, porous membrane system with anti-fouling characteristics is prepared via simple co-infusion of oil and water within hydrophobic and superhydrophilic surfaces of a porous membrane, respectively. This membrane simultaneously repels the immiscible water and oil exhibiting excellent interfacial floatability at the oil-water interface as a separator, thus showing promise for use in applications in the immiscible oil/water separation industry and liquid-liquid extraction.