Ultralow-adhesion icephobic surfaces:Combining superhydrophobic and liquid-like properties in the same surface

As a ubiquitous natural phenomenon,ice/frost formation on solid surfaces have adverse effects on many commercial and residential activities.Icephobic surfaces feature low ice adhesion strengths(<100 kPa)can passively retard ice formation and ease ice removal.Superhydrophobic surfaces and liquid-lubricating surfaces are two prevailing categories of icephobic surfaces.However,their long-term stability is relatively poor,and the ice adhesion strengths are not low enough for passive removal of small ice crystals(e.g.,frosts)from the surfaces.Herein,we combine the superhydrophobic and liquid-like properties in one surface to obtain durable icephobic surfaces with extremely low ice adhesion strengths(about 0.035 kPa).Ices and frosts can be removed from the surface under the action of gravity or gas purge.These surfaces are prepared based on surface nanoconical structure and covalently-grafted liquid-like perfluorinated polyether(PFPE)coating,which show synergy effects on suppressing icing and frosting by promoting expulsion of subcooled condensate droplets from the nanotexture and decreasing ice adhesion strengths.The icephobic surfaces show significantly better durability compared to lubricant-impregnated textured surfaces.Our results provide a new avenue to design passive anti-icing/anti-frosting surfaces for a wide range of applications where surfaces are exposed to humid and low-temperature environments.

Whether and When Superhydrophobic/Superoleophobic Surfaces Are Fingerprint Repellent

Driven by the ever-increasing demand for fingerprint-resistant techniques in modern society,numerous researches have proposed to develop innovative antifingerprint coatings based on superhydrophobic/superoleophobic surface design.However,whether superhydrophobic/superoleophobic surfaces have favorable repellency to the microscopic fingerprint is in fact an open question.Here,we establish a reliable method that enables evaluating the antifingerprint capability of various surfaces in a quantitative way.We show that superhydrophobicity is irrelevant with fingerprint repellency.Regarding superoleophobic surfaces,two distinct wetting states of microscopic fingerprint residues,i.e.,the"repellent"and the“collapsed”states,are revealed.Only in the"repellent"state,in which the fingerprint residues remain atop surface textures upon being pressed,superoleophobic surfaces can bring about favorable antifingerprint repellency,which correlates positively with their receding contact angles.A finger-deformation-dependent intrusion mechanism is proposed to account for the formation of diferent fingerprint wetting states.Our findings offer important insights into the mechanism of fingerprint repellency and will help the design of high-performance antifingerprint surfaces for diverse applications.