Tuning of thin film composite nanofiltration membranes containing poly(vinylidene fluoride)-g-poly(oxyethylene) methacrylate

Thin film composite nanofiltration membranes have applications in many fields ranging from water purification to molecular separations. The microphase separation of amphiphilic graft copolymers consisting of a hydrophobic poly(vinylidene fluoride) (PVDF) backbone and poly (oxyethylene) methacrylate (POEM) side-chains, PVDF-g-POEM, was previously employed to create nanochannel membranes with subnanometer size selectivity [1]. Here we explored means of tuning the molecular size cut-off of these membranes by a simple processing approach: Widening of the hydrophilic nanochannels by the addition of poly(ethylene oxide) (PEO) to the casting solution. PEO is subsequently removed by the immersion of the membrane in a solvent such as isopropanol. [1] A. Akthakul, R.F. Salinaro, A.M. Mayes, Macromolecules 2004, 37, 7663-7668