Durable and regenerative superhydrophobic surface using porous nanochannels

Despite substantial advancements in development of artificially engineered superhydrophobic surfaces, durability and regenerative aspect of such surfaces remain elusive. Harsh working condition, especially extreme exposure to water or humidity deteriorates plastron property of superhydrophobic surfaces rendering them inappropriate for prolonged under-water applications. We report a systematic approach for creating a durable superhydrophobic surface by first plasma-treating a fabricated porous nanochannel geometry on a silicon substrate followed by infusion-depletion of silicon oil and coating a layer of carbon derived from candle soot. The surface is capable of maintaining water contact angle (WCA) of nearly 160^° and roll off angle (ROA) less than 5^° after undergoing 20 different tests including mechanical (tap water jet up to 10.3ms^-1, tape peeling test up to 12 cycles), chemical (saline and solvents immersion), thermal (high temperature exposure and condensation heat transfer), self-cleaning tests, organic compatibility (honey, soy sauce, chocolate syrup, all-purpose flour) and superoleophilic test, thus exhibiting potential real-world applications. The surface retains stable plastron with negligible change in WCA and ROA even after being under 10cm of water for 30 days, similar to respiration plastrons seen on some aquatic insects. Regenerative capability of the surface is demonstrated by restoring its superhydrophobicity from a forced degraded state.