Droplets self-draining on the horizontal slippery surface for real-time anti-/de-icing

As global economic losses from ice storms exceed US $10 billion per year, the limitations of traditional mechanical and chemical de-icing—high energy demand (>5 kW m^-2) and environmental hazards—become more pronounced. Now, researchers from the School of Chemistry at Beihang University, led by Professor Liping Heng and Professor Lei Jiang, have presented a comprehensive study on a self-draining slippery surface (SDSS) that achieves real-time anti-icing on horizontal substrates under sunlight. This work offers valuable insights into next-generation icephobic technologies that overcome these limitations.

Why SDSS Matters
   • Energy Efficiency: SDSS converts 100 mW cm^-2 sunlight into 19.8 ± 2.2 °C surface heating and spontaneous electrostatic repulsion, eliminating external energy input.
   • In-Surface Actuation: By integrating photothermal, pyroelectric and oleogel functions, SDSS enables droplet self-expulsion, drastically reducing re-freezing risk.
   • Horizontal Anti-Icing: Mimicking natural self-cleaning, SDSS acts as an autonomous anti-icing skin ideal for aircraft, power lines and solar panels without tilt.

Innovative Design and Features
   • Tri-Layer Stack: A 50 μm PDMS oleogel slippery film, 500 μm lithium-niobate pyroelectric layer and 600 μm CNTs/PDMS photothermal layer synergistically deliver low-power operation.
   • Functional Materials: Transparent LN (88 % transmittance), high pyroelectric coefficient (~4 × 10^-5 C m^-2 K^-1) and ultra-low sliding angle (<5°) enable sunlight-driven charge transfer and droplet removal.
   • Universal Mechanism: Organic PVDF and inorganic PZT validate the thermo-electric coupling, proving broad material compatibility.

Applications and Future Outlook
   • Multi-Scenario Protection: SDSS clears 10 μL droplets within 8 min at −20 °C and survives 100 freeze–thaw cycles, enabling maintenance-free protection.
   • Tunable Surface Potential: Light intensity (0.5–2.0 kW m^-2) modulates potential from 0 to 12 kV, offering programmable droplet routing.
   • Autonomous Icephobic Neurons: SDSS responds to light, temperature and humidity, performing self-decision ice mitigation.
   • Challenges and Opportunities: Long-term lubricant retention, mechanical durability and scalable fabrication remain; future work targets flexible substrates and roll-to-roll processing.

This comprehensive study provides a roadmap for low-power icephobic surfaces in real-world anti-/de-icing systems, highlighting interdisciplinary research in interfacial science, photothermal materials and electrostatic engineering. Stay tuned for more groundbreaking work from Professor Liping Heng and Professor Lei Jiang at Beihang University!