Effective Approach to Render Stable Dynamic Omniphobicity and Icephobicity to Ultrasmooth Metal Surfaces.

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Surface modification for liquid and solid repellency is less developed for metals compared to silicon or glass.
• Polymethylhydrosiloxane (PMHS) offers covalent immobilization on metals, creating omniphobic surfaces, but lacks hydrolytic stability.

Purpose of the Study:

• To enhance the hydrolytic stability of PMHS-coated metal surfaces.
• To improve the durability and performance of omniphobic coatings on various metals.

Main Methods:

• Covalent immobilization of PMHS on metal surfaces (Ti, Al, Cr, Ni, Cu).
• End-capping of residual Si-H groups in PMHS films using vinyl-terminated organosilanes (e.g., TMVS).
• Platinum-catalyzed hydrosilylation reaction for capping.

Main Results:

• TMVS-capped PMHS films exhibited significantly improved hydrolytic stability, retaining properties after 6 days of water submersion.
• Excellent dynamic dewetting behavior was maintained for water, toluene, n-hexadecane, and ethanol.
• The modified surfaces demonstrated effective anti-icing (icephobic) properties with low ice adhesion (<50 kPa) after 20 freeze-thaw cycles.

Conclusions:

• End-capping PMHS films with TMVS effectively enhances hydrolytic stability on metal surfaces.
• The improved coatings maintain excellent liquid repellency and exhibit useful ice-repellent characteristics.
• This method provides a durable and versatile surface modification strategy for various metals.