Contact angle hysteresis, adhesion, and marine biofouling

Area of Science:

• Materials Science
• Surface Chemistry
• Marine Biology

Background:

• Marine biofouling poses significant challenges for submerged structures, necessitating advanced anti-fouling solutions.
• Developing coatings with controlled surface properties is crucial for effective marine biofouling release.
• Perfluoroalkyl groups are known for their unique surface properties, but their correlation with biofouling release needs further investigation.

Purpose of the Study:

• To investigate the adhesive and marine biofouling release properties of novel coatings.
• To explore the relationship between surface characteristics (contact angle, hysteresis, cross-linking) and coating performance.
• To identify optimized coating formulations for superior marine biofouling resistance.

Main Methods:

• Synthesized coatings by cross-linking specific acrylate and oxazoline copolymers at varying molar ratios.
• Characterized surfaces using X-ray photoelectron spectroscopy and contact angle measurements (static, advancing, receding).
• Assessed adhesion via peel tests and marine biofouling resistance through seawater immersion studies.

Main Results:

• Adhesive release properties did not correlate with surface energy or fluorine content.
• Adhesive properties correlated with water receding contact angles and contact angle hysteresis.
• Optimal coatings with high cross-link density and low contact angle hysteresis demonstrated unprecedented marine biofouling resistance.
• Water contact angle hysteresis showed a correlation with marine biofouling resistance.

Conclusions:

• Wetting hysteresis, rather than surface energy, is a key factor in achieving effective adhesive release from these coatings.
• Optimized perfluoroalkyl-containing coatings offer a promising strategy for combating marine biofouling.
• Contact angle hysteresis serves as a reliable indicator for predicting marine biofouling resistance.