Plasma polymerized fluorocarbon （FC） films have been deposited on silicon substrates from dielectric barrier discharge （DBD） plasma of C4Fs at room temperature under a pressure of 25～125 Pa. The effects of the di...Plasma polymerized fluorocarbon （FC） films have been deposited on silicon substrates from dielectric barrier discharge （DBD） plasma of C4Fs at room temperature under a pressure of 25～125 Pa. The effects of the discharge pressure and frequency of power supply on the films have been systematically investigated. FC films with a less cross linked structure may be formed at a relatively high pressure. Increase in the frequency of power supply leads to a significant increase in the deposition rate. Static contact angle measurements show that deposited FC films have a stable, hydrophobic surface property. All deposited films show smooth surfaces with an atomic surface roughness. The relationship between plasma parameters and the properties of the deposited FC films are discussed.展开更多
Silane coupling reagent （3-mercaptopropyl trimethoxysilane （MPTS）） was prepared on silicon substrate to form two-dimensional Self-Assembled Monolayer （SAM） and the terminal -SH group in the film was in situ oxid...Silane coupling reagent （3-mercaptopropyl trimethoxysilane （MPTS）） was prepared on silicon substrate to form two-dimensional Self-Assembled Monolayer （SAM） and the terminal -SH group in the film was in situ oxidized to -SO3H group to endow the film with good chemisorption ability. Thus, lanthanum-based thin films were deposited on oxidized MPTS-SAM to form rare earth composite thin films （RE thin films）, making use of the chemisorption ability of the -SO3H group. Atomic Force Microscope （AFM）, X-ray Photoelectron Spectrometry （XPS）, and contact angle measurements were used to characterize the RE thin films. Adhesive force and friction force of the RE thin films and silicon substrate were measured under various applied normal loads and scanning speed of AFM tip. The results showed that the friction force increased with applied normal loads and scanning speed of AFM tip. To study the effect of capillary force, tests were performed in various relative humidities. The results showed that the adhesive force of silicon substrate increased with relative humidity and the adhesive force of RE thin films only increased slightly with relative humidity. Research showed that surfaces with higher hydrophobic property reveal lowered adhesive and friction forces.展开更多
The mechanism of activated carbon treatment with chromium-containing wastewater byX-ray photoelectron spectroscopy (XPS) and that of adsorption and reduction reaction of the acti-vated carbon with hexavalent chromium ...The mechanism of activated carbon treatment with chromium-containing wastewater byX-ray photoelectron spectroscopy (XPS) and that of adsorption and reduction reaction of the acti-vated carbon with hexavalent chromium solution are presented in this paper. The XPS results showthat at PH<1,the activated carbon does not adsorb any chromium ion,and the main reaction is re-duction process of Cr(VI), at 1<pH<6, both reduction process of Cr(VI) and adsorption process ofCr(VI) and Cr(III) occur on the carbon surface, at PH >6,the main process is adsorption of the car-bon to Cr(VI). The optimum range of treatment is at pH 3-6,in which removal efficiency ofadsorption and reduction is relatively high. It demonstrates that the reduction mechanism is aheterogeneous acid catalysis process.展开更多
基金National Natural Science Foundation of China(No.10405005)
文摘Plasma polymerized fluorocarbon （FC） films have been deposited on silicon substrates from dielectric barrier discharge （DBD） plasma of C4Fs at room temperature under a pressure of 25～125 Pa. The effects of the discharge pressure and frequency of power supply on the films have been systematically investigated. FC films with a less cross linked structure may be formed at a relatively high pressure. Increase in the frequency of power supply leads to a significant increase in the deposition rate. Static contact angle measurements show that deposited FC films have a stable, hydrophobic surface property. All deposited films show smooth surfaces with an atomic surface roughness. The relationship between plasma parameters and the properties of the deposited FC films are discussed.
基金Project supported by the National Natural Science Foundation of China (50475023)Nano Foundation of Shanghai Technology Committee (0252nm014)State Key Laboratory Fund (0403) in State Key Laboratory of Solid Lubrication
文摘Silane coupling reagent （3-mercaptopropyl trimethoxysilane （MPTS）） was prepared on silicon substrate to form two-dimensional Self-Assembled Monolayer （SAM） and the terminal -SH group in the film was in situ oxidized to -SO3H group to endow the film with good chemisorption ability. Thus, lanthanum-based thin films were deposited on oxidized MPTS-SAM to form rare earth composite thin films （RE thin films）, making use of the chemisorption ability of the -SO3H group. Atomic Force Microscope （AFM）, X-ray Photoelectron Spectrometry （XPS）, and contact angle measurements were used to characterize the RE thin films. Adhesive force and friction force of the RE thin films and silicon substrate were measured under various applied normal loads and scanning speed of AFM tip. The results showed that the friction force increased with applied normal loads and scanning speed of AFM tip. To study the effect of capillary force, tests were performed in various relative humidities. The results showed that the adhesive force of silicon substrate increased with relative humidity and the adhesive force of RE thin films only increased slightly with relative humidity. Research showed that surfaces with higher hydrophobic property reveal lowered adhesive and friction forces.
文摘The mechanism of activated carbon treatment with chromium-containing wastewater byX-ray photoelectron spectroscopy (XPS) and that of adsorption and reduction reaction of the acti-vated carbon with hexavalent chromium solution are presented in this paper. The XPS results showthat at PH<1,the activated carbon does not adsorb any chromium ion,and the main reaction is re-duction process of Cr(VI), at 1<pH<6, both reduction process of Cr(VI) and adsorption process ofCr(VI) and Cr(III) occur on the carbon surface, at PH >6,the main process is adsorption of the car-bon to Cr(VI). The optimum range of treatment is at pH 3-6,in which removal efficiency ofadsorption and reduction is relatively high. It demonstrates that the reduction mechanism is aheterogeneous acid catalysis process.
