| In recent years,the superhydrophobic surface developed by the "Lotus effect" has received more and more attention.This superhydrophobic surface has a large number of excellent application potentials such as self-cleaning,anti-corrosion and the like in an aqueous environment.However,since a surface is not only exposed to water-based substances,it may also be exposed to oily substances with relatively low surface tension,such as soybean oil,diesel oil,etc.These oily substances easily break the super-hydrophobic surface,limiting its self-cleaning and the application of such effects.Therefore,the superamphiphobic surface was proposed to solve these problems.Palygorskite(PAL)is a promising natural clay mineral for the preparation of bionic super anti-wetting coatings,a new application field of PAL.the suspensions were prepared by hydrolytic condensation of1 H,1H,2H,2H-perfluorodecyltriethoxysilane and tetraethoxysilane onto the modified PAL,ultrasonication and stirring were employed to disperse the suspension and promote the condensation,and spraying was employed to get the superamphiphobic coatings finally.The content and results were shown as the follows:(1)the effects of modification of PAL on superamphiphobicity and microstructure of the PAL@fluorinated polysiloxane(PAL@fluoro POS)superamphiphobic coatings were systematically studied.First,PAL was modified via acid activation,solid-state grinding and heat activation.Then,the PAL@fluoro POS coatings were prepared by hydrolytic condensation of1 H,1H,2H,2H-perfluorodecyltriethoxysilane and tetraethoxysilane onto the modified PAL,followed by spay-coating onto substrates.It was found that the microstructure of the coatings is controllable by acid activation and solid-state grinding.Acid activation with HCl at moderate conditions(2 M HCl,15 °C)and grinding for a proper time(10 min)are helpful to improve superamphiphobicity of the coatings by forming smaller protrusions and micropores on the surface of the coatings.On the contrary,heat activation results in decline of the superamphiphobicity,especially at high temperature.The achieved coatings show excellent superamphiphobicity,and are mechanically robust and thermally stable,which can withstandintensive water jetting at 100 k Pa for 20 min and 350 °C for 1 h.Moreover,the coatings can be applied onto various substrates like aluminum foil,PTFE plate,wood plate and polyester textile.We believe that the findings will promote the development of novel clay-based super anti-wetting coatings.(2)Colorful superhydrophobic and superamphiphobic coatings are receiving growing attention,but are very challenging to invent.Here,we report a general method for the preparation of mechanically robust and thermally stable colorful superamphiphobic coatings by the combination of Maya blue and bioinspiration.First,a composite of palygorskite(PAL)nanorods and iron oxide red(IOR)was prepared by solid-state grinding or hydrothermal reaction of PAL with Fe(III)salts,which was then modified by hydrolytic condensation of silanes to form a suspension.Subsequently,the superamphiphobic coatings were prepared by spray-coating the suspension onto substrates.The superamphiphobicity is dependent on the surface microstructure and chemical composition,which are controllable by the PAL/IOR concentration and the solid-state grinding time.The colorful coatings show excellent superamphiphobicity with high contact angles and low sliding angles for water and various organic liquids of low surface tension,e.g.,toluene and n-decane.The coatings also feature high mechanical,chemical and thermal stability up to 400 °C,which is superior to all the reported colorful super anti-wetting coatings.Moreover,superamphiphobic coatings of different colors can be prepared via the same procedure by using the other metal oxides instead of IOR.We believe that the colorful superamphiphobic coatings may find applications in many fields like anti-climbing of oils and restoration of cultural relics,as the coatings are applicable onto various substrates. |
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