A novel super-hydrophobic stearic acid(STA)film with a water contact angle of 166° was prepared by chemical adsorption on aluminum wafer coated with polyethyleneimine(PEI)film. The micro-tribological behavior of ...A novel super-hydrophobic stearic acid(STA)film with a water contact angle of 166° was prepared by chemical adsorption on aluminum wafer coated with polyethyleneimine(PEI)film. The micro-tribological behavior of the super-hydrophobic STA monolayer was compared with that of the polished and PEI-coated Al surfaces.The effect of relative humidity on the adhesion and friction was investigated as well.It was found that the STA monolayer showed decreased friction,while the adhesive force was greatly decreased by increasing the surface roughness of the Al wafer to reduce the contact area between the atomic force microscope(AFM)tip and the sample surface to be tested.Thus the friction and adhesion of the Al wafer was effectively decreased by generating the STA monolayer, which indicated that it could be feasible and rational to prepare a surface with good adhesion resistance and lubricity by properly controlling the surface morphology and the chemical composition.Both the adhesion and friction decreased as the relative humidity was lowered from 65% to 10%,though the decrease extent became insignificant for the STA monolayer.展开更多
To enhance durability and adhesion of superhydrophobic surface,an integrated superhydrophobic calcium myristate(Ca[CH3(CH2)12COO]2)coating with excellent corrosion resistance was fabricated on AZ31 magnesium(Mg)alloy ...To enhance durability and adhesion of superhydrophobic surface,an integrated superhydrophobic calcium myristate(Ca[CH3(CH2)12COO]2)coating with excellent corrosion resistance was fabricated on AZ31 magnesium(Mg)alloy via one-step electrodeposition process.Field-emission scanning electron microscopy,Fourier transform infrared spectrometry and X-ray photoelectron spectroscopy as well as X-ray diff raction were employed to investigate the surface characteristics(morphology,composition and structure)of the coatings.Hydrophobicity of the coating was evaluated by means of contact and sliding angles.Additionally,potentiodynamic polarization,electrochemical impedance spectroscopy and hydrogen evolution tests were conducted to characterize the corrosion resistance.Results indicated that the coating exhibited super-hydrophobicity with large static water contact angle(CA)and small sliding angle of 155.2°±1.5°and 6.0°±0.5°,respectively,owing to spherical rough structure and low surface energy(7.01 mJ m^(-2)).The average hydrogen evolution rate(HERa)and corrosion current density(icorr)of the coated sample were 5.3μL cm^(-2)h^(-1) and 5.60×10^(-9)A cm^(-2),about one and four orders of magnitude lower than that of AZ31 substrate,respectively,implying the excellent corrosion resistance.The CA of the coating remained 155.6°±0.9°after soaking for 13 days,showing the super-hydrophobicity and stability of the coating.Simultaneously,the large critical load(5004 mN)for the coating designated the outstanding adhesion to the substrate by nano-scratch test.展开更多
基金The project supported by the National Natural Science Foundation of China (50375151,50323007,10225209)the Chinese Academy of Sciences (KJCX-SW-L2)
文摘A novel super-hydrophobic stearic acid(STA)film with a water contact angle of 166° was prepared by chemical adsorption on aluminum wafer coated with polyethyleneimine(PEI)film. The micro-tribological behavior of the super-hydrophobic STA monolayer was compared with that of the polished and PEI-coated Al surfaces.The effect of relative humidity on the adhesion and friction was investigated as well.It was found that the STA monolayer showed decreased friction,while the adhesive force was greatly decreased by increasing the surface roughness of the Al wafer to reduce the contact area between the atomic force microscope(AFM)tip and the sample surface to be tested.Thus the friction and adhesion of the Al wafer was effectively decreased by generating the STA monolayer, which indicated that it could be feasible and rational to prepare a surface with good adhesion resistance and lubricity by properly controlling the surface morphology and the chemical composition.Both the adhesion and friction decreased as the relative humidity was lowered from 65% to 10%,though the decrease extent became insignificant for the STA monolayer.
基金supported by the National Natural Science Foundation of China(No.52071191)the Scientific Research Foundation of Shandong University of Science and Technology Research Fund(No.2014TDJH104)。
文摘To enhance durability and adhesion of superhydrophobic surface,an integrated superhydrophobic calcium myristate(Ca[CH3(CH2)12COO]2)coating with excellent corrosion resistance was fabricated on AZ31 magnesium(Mg)alloy via one-step electrodeposition process.Field-emission scanning electron microscopy,Fourier transform infrared spectrometry and X-ray photoelectron spectroscopy as well as X-ray diff raction were employed to investigate the surface characteristics(morphology,composition and structure)of the coatings.Hydrophobicity of the coating was evaluated by means of contact and sliding angles.Additionally,potentiodynamic polarization,electrochemical impedance spectroscopy and hydrogen evolution tests were conducted to characterize the corrosion resistance.Results indicated that the coating exhibited super-hydrophobicity with large static water contact angle(CA)and small sliding angle of 155.2°±1.5°and 6.0°±0.5°,respectively,owing to spherical rough structure and low surface energy(7.01 mJ m^(-2)).The average hydrogen evolution rate(HERa)and corrosion current density(icorr)of the coated sample were 5.3μL cm^(-2)h^(-1) and 5.60×10^(-9)A cm^(-2),about one and four orders of magnitude lower than that of AZ31 substrate,respectively,implying the excellent corrosion resistance.The CA of the coating remained 155.6°±0.9°after soaking for 13 days,showing the super-hydrophobicity and stability of the coating.Simultaneously,the large critical load(5004 mN)for the coating designated the outstanding adhesion to the substrate by nano-scratch test.
