Polyion multilayers with precise surface charge control for antifouling.

Area of Science:

• Materials Science
• Surface Chemistry
• Biomaterials Engineering

Background:

• Controlling surface properties is crucial for developing advanced materials.
• Electrostatic layer-by-layer (LbL) assembly offers a versatile method for fabricating thin films.
• Tuning surface charge is key for applications like antifouling coatings.

Purpose of the Study:

• To establish a molecular fabrication approach for precise control over surface zeta potentials of LbL-assembled polymer films.
• To achieve tunable surface isoelectric points (IEP) in the pH range of 6-10.
• To investigate the antifouling performance of these tailored surfaces against marine organisms and bacteria.

Main Methods:

• Utilized electrostatic layer-by-layer (LbL) assembly with poly(acrylic acid) (PAA) and poly(diallyldimethylammonium chloride) (PDADMAC).
• Incorporated a weak polycation, polyethylenimine (PEI), as the top layer for surface charge manipulation.
• Controlled surface charge by adjusting the ionization degree of weak polyelectrolytes and the amount of deposited polyelectrolyte in the final layers.

Main Results:

• Achieved precise control over surface zeta potentials and IEPs in the pH range of 6-10.
• Demonstrated that negatively charged LbL films attracted more barnacle cyprids (Amphibalanus amphitrite).
• Observed increased bacterial adhesion (Pseudomonas, E. coli, S. aureus) on positively charged LbL films, likely due to bacterial cell wall properties.

Conclusions:

• The developed LbL fabrication protocol allows for fine-tuning of surface charge and IEPs.
• Surface charge plays a significant role in the settlement of barnacle cyprids and bacterial adhesion.
• This method enables the optimization of antifouling performance by tailoring surface properties to specific environmental pH and fouling organisms.