Excellent Anti-Icing Abilities of Optimal Micropillar Arrays with Nanohairs

Anti-icing abilities are achieved on surfaces of micropillar arrays with nanohairs that are fabricated by methods of soft replication and crystal growth, i.e., different micropillar arrays with the similar nanohairs, different nanohairs with the same micropillar arrays. It is demonstrated that an optimal micropillar array with nanohairs contributes an excellent anti-icing or antifogging property at low temperature below zero. As a result, the longest icing delay time is achieved effectively up to ≈9839 s at -10 °C on the optimal surface. As for the optimal surface in humidity, the condensed droplets merge into each other, and meanwhile jump off easily. Accordingly, a largest dry area is up to ≈90.5% at -5 °C in ≈1020 s after breeze action. It is attributed to the stability of less liquid-solid fraction on an optimal surface under low temperature, in addition to cooperation between micropillar arrays and nanohairs in sizes. This finding provides an insight into the design of structure size on micro-nanostructured surface for anti-icing/antifogging ability effectively, which can be extended into the applications in some surfaces of systems, e.g., microdevices worked in cold or humid environment.