Alkali-responsive membrane prepared by grafting dimethylaminoethyl methacrylate onto ethylene vinyl alcohol copolymer membrane

An alkali-responsive membrane was prepared by grafting dimethylaminoethyl methacrylate (DMAEMA) onto ethylene vinyl alcohol copolymer (EVAL) membrane using ultraviolet (UV) irradiation graft polymerization. A subtranslucent state of EVAL membrane swelling in the DMAEMA solution was observed, and such a state enabled the passage of UV light through all the pores, inducing graft polymerization inside the pores and on the back. Attenuated total reflectance Fourier-transform infrared spectrometer (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscope (EDX) confirmed that the poly(DMAEMA)-grafted chains existed not only on the top surface, but also inside the pores and on the back. Atomic force microscopy (AFM) and nitrogen adsorption analysis confirmed that the grafted chains collapsed in air, and decreased the surface roughness, surface area, and pore size of the grafted membranes. Alkali-responsive properties of the poly(DMAEMA)-grafted EVAL membrane (i.e., contact angle, permeability, and selectivity) were observed in the pH range of 9-10. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41775.