Thermo-responsive separation membrane with smart anti-fouling and self-cleaning properties

Smart responsive materials have been attracting increasing interests in membrane separation field. Herein, we reported a new thermo-responsive membrane with interesting anti-fouling and self-cleaning properties. N-isopropylacrylamide grafted silica nanoparticles (SiO₂-PNIPAm) were synthesized via atom transfer radical polymerization (ATRP) and the obtained SiO₂-PNIPAm was incorporated into the polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane via blending method. The physicochemical properties of various modified membranes were thoroughly characterized. The SiO₂-PNIPAm incorporation can readily improve membrane hydrophilicity and the water permeation of PVDF membrane. The water flux cycling tests of PVDF/SiO₂-PNIPAm membranes were conducted by switching temperatures between 25 °C and 37 °C, demonstrating the unique thermo-responsible flux variation and excellent stability. The developed PVDF/SiO₂-PNIPAm membranes showed the enhanced flux recovery rate (FRR) and the decreased values in irreversible fouling ratios compared with that of pristine PVDF membrane. The continuous increase of the Bovine serum albumin (BSA) adsorption–desorption ratio indicated the exceptional self-cleaning property of PVDF/SiO₂-PNIPAm membranes with temperature switching around the lower critical solution temperature (LCST). Therefore, our thermo-responsive membrane with the anti-fouling and self-cleaning abilities has great potentials for membrane water treatment and can inspire the rapid development of smart materials towards environmental applications.