the present application is generally directed towards polyacrylonitrile — based , amphophilic graft copolymers , for example , for the production of membranes for liquid filtration . in one aspect , the present invention provides systems and methods for preparing high flux , fouling resistant nanofiltration membranes whose pore size can be readily tuned . in some cases , microphase separation of a graft copolymer comprising a backbone comprising polyacrylonitrile and hydrophilic side - chains is used . in some cases , nanochannels of tunable width are formed , which may give the membrane permselective properties and / or anti - fouling character . in some cases , a copoylmer may be used as an additive in the immersion precipitation casting of ultrafiltration or microfiltration membranes . in certain instances , the additive can segregate to the membrane exterior and / or pore surfaces , e . g ., due to favorable interactions between the hydrophilic side chains and the surrounding environment , which may create a surface that resists fouling , e . g ., by biological molecules .