Relationships between Water's Structure and Solute Affinity at Polypeptoid Brush Surfaces

Area of Science:

• Materials Science
• Surface Chemistry
• Computational Chemistry

Background:

• Antifouling surfaces are crucial for preventing unwanted material adhesion.
• Zwitterionic functionalities are promising for creating highly effective antifouling surfaces.
• A fundamental understanding of hydration layer structure and its role in antifouling is lacking.

Purpose of the Study:

• To investigate the molecular mechanisms linking surface chemistry, hydration water structure, and solute affinity.
• To explore how zwitterionic surface chemistries achieve antifouling properties.
• To establish a relationship between hydration water structure and antifouling performance.

Main Methods:

• Molecular dynamics simulations were employed to study various polypeptoid-decorated surfaces.
• Free energy calculations were used to determine solute-surface affinities.
• Analysis of hydration water structure in response to different surface chemistries was performed.

Main Results:

• Zwitterionic surfaces exhibit solute-surface repulsion due to highly coordinated hydration water.
• Tetrahedral structuring of water around solutes is suppressed by zwitterionic surfaces.
• Uncharged surfaces, in contrast, show affinity for solutes, indicating a different hydration mechanism.

Conclusions:

• A molecular mechanism for zwitterionic antifouling is proposed, based on hydration water structuring.
• The findings provide insights into tuning surface chemistry for enhanced antifouling.
• This research has broader implications for the design of next-generation antifouling surfaces.