Preparation of Modified Membrane Based on Covalent Grafting of Poly(N-isopropyl acrylamide) on PVDF Membrane Surface by Gamma-Ray Irradiation

Abstract This paper reports on the study that gamma-ray irradiation-induced polymerization of N-isopropyl acrylamide (NIPA) to form Poly(N-isopropyl acrylamide) (PNIPA), which was then grafted on the surface of polyvinylidene fluoride (PVDF) membrane to prepare modified PVDF-g-PNIPA membrane. We analyzed the influence of different irradiation doses and dose rates on the grafting rate of modified membranes, and the grafting rate increased with the irradiation dose under a certain irradiation dose. Through analysis of Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TGA), the efficient progress of the grafting reaction was confirmed. With the increase of the grafting rate, the pore size of the membrane surface decreased gradually, but the surface roughness of the membrane tended to increase through the analyse of scanning electron microscopy (SEM) and atomic force microscopy (AFM). Finally, a mechanistic explanation for the grafting of PNIPA on the surface of PVDF membranes based on these experimental results was proposed.