Fabrcation Of Slippery Liquid-infused Porous Surfaces And The Effect Of Interface Structure On The Slippery Behavior

The superhydrophobic surface based on lotus-effect has attracted widespread attention.However,to repel liquids,these surfaces rely on trapped air which is prone to escape under conditions involving high temperature,pressure,humidity,hydrodynamic shear and when exposed to low surface tension liquids.This results in an unavoidable failure of their liquid-repelling functionSlippery liquid infused porous surfaces(SLIPS)are new surfaces with self-cleaning based on Nepenthes-effect.These surfaces have a capability to repel various simple and complex liquids,such as,water,methanol,glycerol,saline solution and so on.They can also resist high pressure and quickly self-heal after physical damage.However,the effect of multiple phase structures on the motion of drops has not been thoroughly addressed.In the present work,liquid-infused porous surfaces were fabricated on porous anodic alumina templates(AAOs)with different geometrical structure parameters.The wetting ability of different liquids on this liquid-infused porous surface was studied.A relationship between the surface structure and wetting ability of liquid-infused AAOs was proposed based on the "Cassie-Baxter state".1H,1 H,2H,2H-perfluorodecyltriethoxysilane(PFD S)or methyltriethoxysilane(MTES)was grafted on the surface of AAO templates to obtain various hydrophobic surfaces.field-emission scanning electron microscope(SEM),energy dispersive spectrometer(EDS)and contact angle(CA)were used to characterize the surface structure,chemical composition and wetting ability of the surface.Results showed that AAOs have ordered structures withpore diameters 24.69±2.47 nm(A),44.00±4.00 nm(B),112.50±12.50 nm(C)and 327.87±9.81 nm(D),respectively.The bare AAOs suface were all hydrophilic before chemical modification,and the water contact angles(WCAs)were 28.4±0.3°,28.2±0.4°,28.8±0.4° and 39.5±0.5°,respectively.With the increase of pore diameters,the WCAs on the surfaces of AAOs modified with PFDS were 130.0±0.2°,133.3±0.2°,137.1±0.3° and 145.1±0.3°,respectively.WCAs on the surfaces of AAOs modified with MTES were 94.5±0.3°,110.8±0.3°,98.05±0.2° and 121.2±0.3°,respectively.Thus,a low surface energy can enhance the hydrophobicity of the surface.The nanopore diameter plays an important role for the apparent WCA on the hydrophobic nanoporous surface.When the pore diameter is small,the hydrophobicity was main contributedby PFDS and MTES.The smallest fraction of water-solid contact area at the base of the water droplet is important for a hydrophobic nanoporous surface.The infused polydimethylsiloxane AAOs with different viscosities(100 mPa.s/20 ? and 350 mPa.s/20 ?)by were obtained The structure of the surfaces was characterized by SEM.Silicone oil was filled into the AAOs,.The wettability of different liquids on silicone-infused AAOs was measured by CA.The relationship between the surface structure and wetting ability of liquid-infused AAOs was studied.The results showed that silicone-infused AAOs have a capability to repel not only water but also some liquids,such as,methanol,glycerol,and saline solution.The water sliding angle(WSA)values decrease with porosity increasing.The smallest WSA was 10.7°,while the largest was 51°.The static water contact angles on the silicone-infused AAOs surfaces were mainly dependent on the non-wetting ability of the lubricant retained in the pores.However,WSA were sensitive to the texture geometry and exhibited a strong negative linear correlation with the area ratio of the lubricant on the surface.A proposed equation containing a critical factor P(porosity)is a good model for the relationship between the WSA and texture geometry.This suggests that the water droplet slippery property can be altered by changing the porosity of the substrate for fabricating specific SLIPS.Moisture-curing polyurethanes with good properties are widely used in biology,medical,construction,automobile and other fields.But of the poor heat resistance of polyurethanelimited their applications.we used DMP-30??as a catalyst to synthesis isocyanurate modified polyurethanes.The synthesis process of MDI??was tracked byfourier transform infrared spectroscopy(FT-IR).The relationships between the area of the characteristic peak of NCO of FTIR and the mass fraction of NCO,the conversion of NCO and the reaction time were studied.The effect of the mixing methods of MDI polymerization products and polyurethanes,the degree of MDI polymerization and the mass fraction of MDI on the heat-resistantof polyurethane was also studied.The results showed that heat-resistance and the mechanical properties before and after aging at 180? ×30 min of polyurethane with isocyanurate ring were better than polyurethane prepolymers.