A Versatile Method for Creating Ultrathin Films of Polyzwitterions with Antifouling Properties

Area of Science:

• Materials Science
• Polymer Chemistry
• Surface Science

Background:

• Protein repellent (antifouling) properties of polymeric films are typically attributed to steric hindrance from adsorbed polymers.
• Previous studies suggested antifouling properties are independent of polymer hydrophilicity for uncharged polymers.

Purpose of the Study:

• To test the hypothesis that antifouling properties are independent of hydrophilicity for charged polymers.
• To develop a grafting method for creating ultrathin polyzwitterion films on solid surfaces.

Main Methods:

• Synthesized poly[1-(3-sulfopropyl-1)-2-vinylpyridinium betaine] (P2VPPS) via free-radical polymerization.
• Immobilized P2VPPS onto quartz or Si/SiO_x substrates using a photoreactive benzophenone derivative cross-linker and silane anchor.
• Utilized 365 nm UV curing for creating ultrathin films (<10 nm dry thickness).

Main Results:

• Developed a grafting method yielding hydrophilic ultrathin polyzwitterion films that rearrange in water.
• Evaluated antifouling performance against *Pseudomonas aeruginosa* strain PAO1.
• Achieved significantly reduced bacterial attachment: ~0% for drop-casted and ~5% for spin-coated films after 4 hours on quartz substrates.

Conclusions:

• The developed grafting method successfully generates ultrathin polyzwitterion films with potent antifouling properties.
• The study extends the understanding of antifouling mechanisms to charged polymer systems.
• These ultrathin polyzwitterion films show promise for creating surfaces resistant to biofouling.