Non-templated manufacturing of patterned fluoropolymer membranes via immersion precipitation printing

Fluoropolymers are amongst the most common polymers used for the fabrication of filtration membranes. Despite this, commercial production of these membranes remains dominated by simple casting and solvent phase separation. Herein, we show a rapid, simple approach to produce fluoropolymer membranes, with a porous patterned surface, via immersion precipitation printing (ipP). The patterns can act as a permeate spacer, which are traditionally added to a membrane separately to induce turbulent flow and subsequently decreasing membrane fouling. The direct phase inversion of the permeate spacer during membrane production induces a porous morphology. Further, intimate mechanical connection between the membrane surface and permeate spacer was observed. Pure water permeability studies were performed on membranes and membranes with patterns (spacers) fabricated with a combination of different fluoropolymer materials (polyvinylidene difluoride (PVDF) and synthesised dehydrofluorinated PVDF (dPVDF)), with a polyvinylpyrrolidone (PVP) (pore forming agent). This simple ipP approach shows potential as a viable alternative for the production of fluoropolymer membranes where the complete control over pattern height, fidelity, and shape is required.