Improved reverse osmosis thin film composite biomimetic membranes by incorporation of polymersomes

Abstract

Biomimetic aquaporin-based membranes offer great promise as a disruptive water treatment technology, due to their potential of improving membrane permeability without compromising solute rejection. However, fabrication upscaling is challenging and therefore the technological potential of biomimetic membranes remains unused. We propose an easily upscalable process based on bulk hydration of diblock and triblock copolymer mixture for preparation of polymersomes which can reconstitute aquaporin proteins. Such polymersomes are incorporated into biomimetic membranes via polyamide active layer synthesis based on interfacial polymerization. By incorporation of blank polymersomes, it was possible to improve water permeability of the membrane by 30%, and by incorporation of aquaporin reconstituting polymersomes by 50%, compared to the membranes without polymersomes. In both cases NaCl rejection was not affected. X-ray photoelectron spectroscopy measurements confirmed incorporation of copolymers prepared with aquaporins into the active polyamide layer without affecting the thickness of the membrane's active layer and surface zeta-potential.