A micro-nano composite superhydrophobic surface with good frost suppression performance and durability

Original Manuscript Draft In this study, a type of micro-nano composite superhydrophobic surface with a micron-level blind hole structure was designed and fabricated. The fabricated composite superhydrophobic surface exhibits better frost suppression performance and durability than a nanoscale superhydrophobic surface. Compared with the nanoscale superhydrophobic surface, the appearance time of the initial frost crystals on the micro-nano composite superhydrophobic surface is extended by 34.7%. Further, the frost-layer growth and covering rates of the micro-nano composite superhrdrophobic surface are considerably reduced. During the defrosting process, the micro-nano composite superhydrophobic surface has fewer residual droplets than the nanoscale superhydrophobic surface. In addition, the micro-nano composite superhydrophobic surface shows the best performance in durability tests. The nanoscale superhydrophobic surface reaches the durability limit after 21 defrosting cycles and becomes a hydrophilic surface. Meanwhile, the composite superhydrophobic surface with a rolling angle of > 90(o) maintains durability until the 27th cycle.