Structure and performance of poly(vinylidene fluoride) membrane with temperature-sensitive poly(n-isopropylacrylamide) homopolymers in membrane pores

The poly(vinylidene fluoride) (PVDF)/poly(N-isopropylacrylamide) (PNIPAM) blend membranes with different PNIPAM contents are prepared by phase inversion of PNIPAM and PVDF in aqueous medium. The membranes are characterized by thermal gravimetric analyses, elemental analysis, Fourier transform infrared spectrometer, X-ray photoelectron spectroscopy, and scanning electron microscope photographs. The results indicate that PNIPAM chains are largely distributed in membrane pore other than membrane surface, and furthermore, with the increase of PNIPAM content, the porous size, porosity, and water flux through the membrane increase, the hydrophilicity and antiprotein fouling are enhanced. The blend membrane exhibits temperature-sensitive permeability to aqueous solutions, with the most drastic change being observed at the lower critical solution temperature (LCST) of PNIPAM (around 32 degrees C). Below the LCST, the blend membrane shows a high protein rejection and a low water flux; above the LCST, the blend membrane shows a low protein rejection and a high water flux. POLYM. COMPOS., 2013. (c) 2013 Society of Plastics Engineers