[Surface modification of polyvinylidene fluoride (PVDF) membrane by using the zwitterionic substance]

Area of Science:

• Materials Science
• Polymer Chemistry
• Membrane Technology

Background:

• Poly(vinylidene fluoride) (PVDF) membranes often suffer from poor hydrophilicity and fouling.
• Enhancing membrane surface properties is crucial for efficient separation processes.

Purpose of the Study:

• To improve the hydrophilicity and antifouling capabilities of PVDF membranes.
• To graft poly(2-hydroxyethyl methacrylate) (poly(HEMA)) and a zwitterionic polymer onto PVDF membrane surfaces.

Main Methods:

• Atom transfer radical polymerization (ATRP) for initial poly(HEMA) grafting.
• Radical polymerization for subsequent grafting of poly(3-(methacryloylamino)propyl-dimethyl-(3-sulfopropyl) ammonium hydroxide) (poly(MPDSAH)).
• Characterization using ATR-FTIR, XPS, SEM, and contact angle measurements.

Main Results:

• Surface modification significantly increased hydrophilicity, evidenced by a decrease in water contact angle from 77.2° to 41.7°.
• Grafting density increased with time, leading to smaller pore sizes and reduced porosity.
• Antifouling performance improved, with reduced bovine serum albumin (BSA) adsorption and a flux recovery ratio up to 94.96% at a grafting density of 288.340 µg/cm².

Conclusions:

• The dual grafting strategy effectively enhances PVDF membrane performance.
• Optimal grafting time of 2 hours yielded a grafting density of 288.340 µg/cm², providing superior antifouling properties.
• Modified membranes show great potential for water treatment applications.