Surface modification of PVDF membrane by radiation-induced admicellar polymerization of acrylamide in the presence of cationic surfactant

Abstract

This article discusses the admicellar polymerization induced by radiation on the poly(vinylidene fluoride) (PVDF) membrane. There are four major stages of admicellar polymerization, which are admicelle formation, adsolubilization, polymerization, and purification. The polymerization stage was realized by using cobalt-60 (Co-60) gamma ray and PVDF as a membrane in water treatment processes, but the use of the latter is restricted due to its inherent hydrophobicity, high fouling tendency, and lack of functional groups. Therefore, this study aims to improve the water flux and permeation efficiency of the PVDF membrane by incorporating complex coordination functional groups, such as amino and carboxyl groups. Acrylamide (AAm) was radiation-grafted onto PVDF membrane in the presence of cationic surfactant, inducing admicellar polymerization. The PAAm-grafted PVDF membrane was obtained by varying the monomer concentration and irradiation dose, while the degree of grafting was found to be proportional to the concentration of monomer and irradiation dose. The changes in properties of PVDF-g-PAAm were investigated by Fourier-transform infrared (FTIR) spectroscopy, thermogravimetry, atomic force microscopy (AFM), scanning electron microscopy (SEM), and contact angle measurement. As the amount of polyacrylamide grafted increased, the hydrophilicity introduced by AAm grafting improved in water flux.