Dynamic pressure‐driven covalent assembly of inner skin hollow fiber multilayer membrane

A covalent assembly was accomplished onto hollow fibers via a dynamic pressure‐driven layer‐by‐layer (LbL) technique. The covalent crosslinking multilayers were successfully formed onto the inner surfaces of hollow fiber porous substrates during the alternatively filtration of polyethyleneimine (PEI) and glutaraldehyde (GA) solutions. The formation of covalent bond between PEI and GA was confirmed using fourier transform infrared (FTIR) spectra. The thickness increment on a quartz slide clearly suggested the stepwise growth of multilayer at nanometer scale. The regular alternation of zeta potentials demonstrated that the successful formation of GA‐crosslinked PEI multilayers on the hollow fibers. The multilayer membranes showed excellent pervaporation performances for the dehydration of different solvent–water mixtures. The selectivity and permeability can be controlled by varying the PEI layer number. More importantly, the covalent assembled multilayer membrane rendered much higher stabilities compared with those from electrostatically LbL assembly, which offers much opportunity for practical applications. © 2010 American Institute of Chemical Engineers AIChE J, 2011