Solvent-induced immiscibility of polymer brushes eliminates dissipation channels

Area of Science:

• Surface Science
• Polymer Chemistry
• Tribology

Background:

• Polymer brushes offer low friction and wear, crucial for industrial uses.
• Interdigitation of opposing brushes can lead to significant damage.

Purpose of the Study:

• To investigate if immiscible polymer brush systems can form stable, low-friction interfaces.
• To explore the tribological potential of such systems.

Main Methods:

• Molecular dynamics simulations were employed to model brush interactions.
• Friction force microscopy experiments were conducted on hydrophilic and hydrophobic brushes in symmetric and asymmetric configurations.

Main Results:

• Simulations showed immiscible brushes form slick interfaces, eliminating interdigitation and reducing energy dissipation.
• Experimental results aligned with simulations, demonstrating friction reduction in both symmetric and asymmetric setups.
• The findings were validated for fully immersed contacts.

Conclusions:

• Immiscible polymer brush systems can slide at a fluid-fluid interface, maintaining load-bearing capacity.
• These systems present a promising solution for tribological applications requiring low friction and wear resistance.