Effect of N-isopropylacrylamide and graphene oxide on the microstructure and performance of thermo-responsive membranes by Ce (IV)-induced redox radical polymerization

In this study, a series of novel thermo-responsive materials were synthesized using polyvinylidene fluoride, N-isopropylacrylamide (NIPAM) and graphene oxide (GO) via Ce (IV)-induced redox radical polymerization name as PNG. Thermo-responsive membranes were prepared by non-solvent induced phase separation. The results demonstrated that the C O and N-H stretching absorption intensities increased with the addition of NIPAM. XPS analysis demonstrated that the PNG1 membrane exhibited abundant functional group structure under the dosage of NIPAM at 1 g. The finger-like porous structure of membrane became longer and wider with the addition of NIPAM at 1 g, leading to a maximum porosity of 45.5 %. The CA decreased from 62.4 ° to 49.0 ° at 35 °C under the adding dosage of NIPAM at 1 g. The temperature-sensitive of PNG1 membrane was 35 °C. In addition, The PNG1 membrane had the lower R ir and higher flux recover than the others under the BSA rejection. According to the XDLVO theory analysis, the total interaction energy for PNG1 membrane achieved the maximum absolute values of −33.850 mJ/m 2 and −19.956 mJ/m 2 than the others under the temperature at 25 °C and 35 °C. This interaction influenced the adsorption between the pollutant and membrane surface, resulting in reversible fouling.