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.

Balance of Polyacrylate-Fluorosilicone Block Copolymers as Icephobic Coatings

Polyacrylate-fluorosilicone block copolymers, namely, polyacrylate-b-polydimethylsiloxane and polyacrylate-bpolymethyltrifluoropropylsiloxane were synthesized for fabricating icephobic coatings. The surface morphology and chemical composition of the block copolymers were characterized by atomic force microscopy and X-ray photoelectron spectroscopy, suggesting that the fluorosilicone blocks aggregated on the top of the copolymer surfaces. Results of water contact angles and ice shear strength demonstrated a certain amount adding of methacryloisobutyl polyhedral oligomeric silsesquioxane could lead to the decrease of contact angle hysteresis and increase of surface roughness, consequently resulting in significant reduction of the ice adhesion strength. Therefore, the block copolymers with the combined advantages of silicone and fluoropolymers could be potentially applied as icephobic coatings.

Investigation of Heterogeneous Ice Nucleation on the Micro-Cubic Structure Superhydrophobic Surface for Enhancing Icing-Delay Performance

The aim of this study is to explore the heterogeneous ice nucleation behavior based on controllable micro-cubic array structure surfaces from the statistic perspective.To this end,we firstly constructed a group of micro-cubic array structures on silicon substrates by a selective plasma etching technique.After grafting low-free-energy substance,the as-constructed micro-cubic array structure surfaces exhibited higher non-wettability with the water contact angle being up to 150°.On this basis,500 cycles of freezing and melting processes were accurately recorded to analyze the instantaneous ice nucleation behavior according to the statistical results of freezing temperature.As a consequence,the statistical freezing temperature of the sample with micro-spacing distance of 40μm is as low as−17.13°C.This microstructure configuration(conforming to Cassie-Baxter wetting regime)not only could entrap more air pockets,but also achieved lower solid-liquid contact area,resulting in lower ice nucleation rate(~2–3 orders of magnitude less than that on the flat substrate).Furthermore,the gradually increasing micro-spacing distance to 60μm would induce the transition from CassieBaxter to Wenzel wetting state,leading to higher freezing probability and ice nucleation rate.The complete understanding on microstructure configuration improving the ice nucleation will lay the foundation stone for the microstructure design of ice-repellent materials.

Superior anti-icing strategy by combined sustainable liquid repellence and electro/photo-responsive thermogenesis of oil/MWNT composite

This paper introduces an effective anti-icing strategy that uses passive anti-icing property and active de-icing functions concurrently.These dual capabilities can alleviate the icing problem more effectively than either a passive or active function alone.The developed material is a slippery liquid-repellent elastic conductor(SLEC);it is an organogel that is composed of multi-walled carbon nanotubes,oil,and polydimethylsiloxane.The SLEC maintains passive water-droplet sliding ability even on wet surfaces that frequently occur in cold conditions(e.g.,during condensation and defrosting),suppresses ice nucleation,and shows ice adhesion strength as low as^20 kPa.The SLEC releases heat when it is subject to electrical or photonic stimulation,and can therefore it can prevent ice formation and melt ice that has already formed on a surface.This material has sustainable liquid repellence by syneresis and replenishment;this ability ensures long-lasting anti-icing property,and results in exceptional durability.This durability is stable against mechanical damage.The superior dual anti-icing capabilities together with the sustainable and stable liquid repellence should generate synergistic effects,and yield a powerful anti-icing tool that can broaden the range of icing applications.

Slippery Photothermal Trap for Outstanding Deicing Surfaces

Ice accumulation is a safety and operational threat in power lines,wind turbines,and transportations.Surfaces having both passive anti-icing and active deicing functionalities are very rare.Here,we report a self-cleaning slippery photothermal trap,which is icephobic passively and deice the surfaces actively by converting sun light to heat at the ice-substrate interface.The photothermal trap consists of three layers:a candle soot layer act as solar radiation absorber,a magnetic iron oxide Fe_(3)O_(4) nanoparticles layer act as heat spreader for lateral dispersal of sun light,and Room Temperature Vulcanized(RTV)insulation to reduce the transverse heat loss.Upon illumination under microsolar 300,the temperature of the surface increased by 40℃ within 200 s.The heat confinement at the magnetic Fe_(3)O_(4) na-noparticles layer leads to rapid increase of the surface temperature,ice start to melt and silicone lubricant facilitates the ice removal.The slippery photothermal trap removed the frozen droplet(10 fiL)within 40 s upon the illumination of sun light and the frozen droplet was completely converted into water after 7 min illumination of solar light at-20℃.The developed slippery photothermal trap also melted the fully frost covered layer within 100 s at-20℃ under sunlamp.The average defrosted length(25 mm)was also observed by irradiation of laser light for 45 s.The self-cleaning slippery photothermal coating showed outstanding deicing performance at subzero temperature for long term due to the infusion of silicone oil into the nanostructures and same chemical composition with binder.

Enhanced anti-icing properties of branched PDMS coatings with self-regulated surface patterns

Adverse impact of icing,on either infrastructures or facilities,is the great impulsion for seeking anti-icing coatings with high performance.In this work,durable icephobic coatings with self-regulated surface patterns were developed from branched polydimethylsiloxane(PDMS)co-crosslinked with fluorinated polyhedral oligomeric silsesquioxane(POSS)through a breath figure method.The prepared coatings with patterned microstructures on the surfaces exhibited excellent anti-icing performance ascribed to micro-crack generation between ice and coating surface under a small external force.The stable cross-linked network composed of branched PDMS and fluorinated POSS endowed the coatings with durability and abrasion resistance.Low ice shear strength was achieved at approximate 19.7±2.5 kPa on coating surface with self-regulated honeycomb pattern.After experiencing 30 icing/deicing cycles,the ice shear strength of the coating varied slightly.Additionally,owing to dedication of fluorinated POSS,the coating showed merely a little increase in ice shear strength after more than 1600 abrasion cycles,which was still in the icephobic range below 50 kPa.Hence,the prepared coatings with remarkably enhanced anti-icing performance and superior mechanical stability would be promising for the practical applications.

超耐用疏冰涂层的制备及性能研究

被动疏冰涂层作为一种新形防除冰方法,拥有环境友好、耗能低、经济等优势,因此在过去十几年来被广泛研究.但是,目前的主动疏冰涂层仍存在疏冰性与耐久性难以兼容的问题.本文设计了一种兼具高韧性、强基底粘附力和自愈合能力的透明疏冰涂层.涂层具有疏水性、光滑表面及低模量,保障了涂层的低冰粘附强度.通过引入类海绵结构,冰粘附强度可降低至26.7±1.1 kPa.涂层高分子网络的多重氢键赋予其高韧性、强基底粘附力和自愈合能力.因此,涂层在35次结冰/除冰循环和600次机械磨损之后能避免涂层剥离并保持疏冰性,且能愈合机械磨损恢复其疏冰性.另外,涂层在海水及近北极气候暴露8个月后仍能保持良好的疏冰性.该工作为耐久性疏冰涂层的设计提供了一种新思路.