Icephobic Surfaces Induced by Interfacial Nonfrozen Water.

Area of Science:

• Materials Science
• Surface Chemistry
• Tribology

Background:

• Smooth, hydrophobic surfaces exhibit low ice adhesion, approaching a limit of ~150 kPa defined by the water receding contact angle.
• Overcoming this limit is crucial for applications requiring effective ice shedding and reduced ice adhesion.

Purpose of the Study:

• To design and investigate novel self-lubricating icephobic coatings.
• To achieve ice adhesion strengths substantially lower than previously reported limits.
• To elucidate the molecular mechanisms responsible for reduced ice adhesion.

Main Methods:

• Development of icephobic coatings by blending polydimethylsiloxane (PDMS)-poly(ethylene glycol) (PEG) amphiphilic copolymers into a polymer matrix.
• Measurement of ice adhesion strength.
• Confirmation of non-frozen water molecules at the ice-solid interface using solid-state nuclear magnetic resonance (NMR) spectroscopy.

Main Results:

• The developed self-lubricating coatings achieved low ice adhesion strength values of approximately 50 kPa.
• These values are substantially lower than the ~150 kPa limit observed on smooth, hydrophobic surfaces.
• Solid-state NMR confirmed the presence of a non-frozen, liquid-like water layer at the ice-coating interface.

Conclusions:

• Self-lubricating icephobic coatings based on PDMS-PEG copolymers effectively reduce ice adhesion strength.
• The PEG component facilitates hydrogen bonding with water, creating a non-freezing interfacial layer that acts as a lubricant.
• This approach offers a promising strategy for surpassing existing limitations in ice adhesion reduction.