This　study　leverages　the　ancient　craft　of　weaving　to　prepare　membranes　that　can　effectively　treat　oil/water　mixtures,　specifically　challenging　nanoemulsions.　Drawing　inspiration　from　the　core-shell　architecture　of　spider　silk,　we　have　engineered　fibers,　the　fundamental　building　blocks　for　weaving　membranes,　that　feature　a　mechanically　robust　core　for　tight　weaving,　coupled　with　a　CO2-responsive　shell　that　allows　for　on-demand　wettability　adjustments.　Tightly　weaving　these　fibers　produces　membranes　with　ideal　pores,　achieving　over　99.6%　separation　efficiency　for　nanoemulsions　with　droplets　as　small　as　20　nm.　They　offer　high　flux　rates,　on-demand　self-cleaning,　and　can　switch　between　sieving　oil　and　water　nanodroplets　through　simple　CO2/N-2　stimulation.　Moreover,　weaving　can　produce　sufficiently　large　membranes　(4800　cm(2))　to　assemble　a　module　that　exhibits　long-term　stability　and　performance,　surpassing　state-of-the-art　technologies　for　nanoemulsion　separations,　thus　making　industrial　application　a　practical　reality.