Fluoroalkyl end-capped acrylic acid oligomer [RF-(ACA)n-RF]/hexagonal boron nitride (h-BN) nanocomposites [RF-(ACA)n-RF/h-BN] were prepared by reaction of the corresponding oligomer with h-BN nanoparticles (mean diame...Fluoroalkyl end-capped acrylic acid oligomer [RF-(ACA)n-RF]/hexagonal boron nitride (h-BN) nanocomposites [RF-(ACA)n-RF/h-BN] were prepared by reaction of the corresponding oligomer with h-BN nanoparticles (mean diameter: 50 nm) under non-catalytic or alkaline conditions, respectively. Fluoroalkyl end-capped N,N-dimethylacrylamide oligomer/h-BN nanocomposites [RF-(DMAA)n-RF/h-BN] were also obtained under similar conditions. It was demonstrated that RF-(ACA)n-RF/h-BN nanocomposites, which were prepared under alkaline conditions, afforded a clear weight loss in proportion to the contents of the oligomer in the composites after calcination at 800°C;however, the non-catalytic conditions enabled the RF-(ACA)n-RF/h-BN nanocomposite to give no weight loss behavior corresponding to the contents of the oligomer even after calcination. In fact, it was demonstrated that the RF-(ACA)n-RF/h-BN nanocomposites possessing a clear weight loss property could afford the fluorescent peak around 370 nm related to h-BN in the composites;however, the same fluorescent intensity of this nanocomposite after calcination at 800°C as that of the original h-BN was observed, indicating that this nanocomposite could give a clear weigh loss behavior corresponding to the content of the oligomer during the calcination process. In contrast, the RF-(ACA)n-RF/h-BN nanocomposites possessing no weigh loss behavior were found to exhibit the similar fluorescent intensity before and even after calcination at 800°C, suggesting that the corresponding nanocomposites could provide no weight loss ability corresponding to the contents of the oligomer in the composites even after calcination. Similarly, RF-(DMAA)n-RF/h-BN nanocomposites, which were prepared under non-catalytic or alkaline conditions, were found to provide no weight loss corresponding to the contents of the oligomer even after calcination, respectively. These fluorinated h-BN nanocomposites were applied to the surface modification of PMMA [poly(methyl methacrylate)] to exhibit an oleophobic pr展开更多
The effects of boundary (liquid/solid) slip on hydrodynamics are well recognized.However,it is extremely difficult to quantify in-situ boundary slip in a lubrication contact.Therefore,an effective interfacial paramete...The effects of boundary (liquid/solid) slip on hydrodynamics are well recognized.However,it is extremely difficult to quantify in-situ boundary slip in a lubrication contact.Therefore,an effective interfacial parameter that is well correlated with the lubrication effect is of practical significance.This paper presents an examination of common interfacial parameters,including surface tension,contact angle,contact angle hysteresis,and a recently proposed spreading parameter.Specimen surfaces of different hydro/oleophobicity were prepared and characterized using the aforementioned interfacial parameters.These samples were further used as bearing surfaces in hydrodynamic lubrication tests.The correlations of these parameters with the measured lubricating film thickness were examined and compared.The key parameter closely related to the hydrodynamic effect was identified.展开更多
A functional fabric with hierarchical structure consisting of basalt fibre fabric as a substrate and polyvinyl alcohol as a coating was developed,aiming at providing a low cost and high-performance way to separate hig...A functional fabric with hierarchical structure consisting of basalt fibre fabric as a substrate and polyvinyl alcohol as a coating was developed,aiming at providing a low cost and high-performance way to separate highly emulsified oil in water.The coating functioned as a hydrophilic gate for the penetration of water in the emulsion,whereas the micro-channels formed in the fabric offered capillary force for the continuous flow of water.The synergy of these two materials led to the increase on the oil concentration in the liquid,which in turn enhanced the collision of emulsified oil droplets to aggregate into large ones in the emulsion and resulted separation from the water.Based on these findings,an aggregation-induced demulsification process was proposed to explain the above phenomenon,and the mechanism was confirmed by studying the distribution of oil droplets in emulsion with a controlled separation degree.展开更多
文摘Fluoroalkyl end-capped acrylic acid oligomer [RF-(ACA)n-RF]/hexagonal boron nitride (h-BN) nanocomposites [RF-(ACA)n-RF/h-BN] were prepared by reaction of the corresponding oligomer with h-BN nanoparticles (mean diameter: 50 nm) under non-catalytic or alkaline conditions, respectively. Fluoroalkyl end-capped N,N-dimethylacrylamide oligomer/h-BN nanocomposites [RF-(DMAA)n-RF/h-BN] were also obtained under similar conditions. It was demonstrated that RF-(ACA)n-RF/h-BN nanocomposites, which were prepared under alkaline conditions, afforded a clear weight loss in proportion to the contents of the oligomer in the composites after calcination at 800°C;however, the non-catalytic conditions enabled the RF-(ACA)n-RF/h-BN nanocomposite to give no weight loss behavior corresponding to the contents of the oligomer even after calcination. In fact, it was demonstrated that the RF-(ACA)n-RF/h-BN nanocomposites possessing a clear weight loss property could afford the fluorescent peak around 370 nm related to h-BN in the composites;however, the same fluorescent intensity of this nanocomposite after calcination at 800°C as that of the original h-BN was observed, indicating that this nanocomposite could give a clear weigh loss behavior corresponding to the content of the oligomer during the calcination process. In contrast, the RF-(ACA)n-RF/h-BN nanocomposites possessing no weigh loss behavior were found to exhibit the similar fluorescent intensity before and even after calcination at 800°C, suggesting that the corresponding nanocomposites could provide no weight loss ability corresponding to the contents of the oligomer in the composites even after calcination. Similarly, RF-(DMAA)n-RF/h-BN nanocomposites, which were prepared under non-catalytic or alkaline conditions, were found to provide no weight loss corresponding to the contents of the oligomer even after calcination, respectively. These fluorinated h-BN nanocomposites were applied to the surface modification of PMMA [poly(methyl methacrylate)] to exhibit an oleophobic pr
基金The work described in this paper was fully supported by the Research Grants Council of Hong Kong，Natural Science Foundation of China
文摘The effects of boundary (liquid/solid) slip on hydrodynamics are well recognized.However,it is extremely difficult to quantify in-situ boundary slip in a lubrication contact.Therefore,an effective interfacial parameter that is well correlated with the lubrication effect is of practical significance.This paper presents an examination of common interfacial parameters,including surface tension,contact angle,contact angle hysteresis,and a recently proposed spreading parameter.Specimen surfaces of different hydro/oleophobicity were prepared and characterized using the aforementioned interfacial parameters.These samples were further used as bearing surfaces in hydrodynamic lubrication tests.The correlations of these parameters with the measured lubricating film thickness were examined and compared.The key parameter closely related to the hydrodynamic effect was identified.
基金Western Light Foundation of Chinese Academy of Sciences,Grant/Award Numbers:2019-XBQNXZB-010,2019-JCTD-001Poverty Alleviation Program of CAS,Grant/Award Number:KFJ-FP-202103Program forAttracting High-Level Talents in Xingjiang Uyghur Autonomous Region。
文摘A functional fabric with hierarchical structure consisting of basalt fibre fabric as a substrate and polyvinyl alcohol as a coating was developed,aiming at providing a low cost and high-performance way to separate highly emulsified oil in water.The coating functioned as a hydrophilic gate for the penetration of water in the emulsion,whereas the micro-channels formed in the fabric offered capillary force for the continuous flow of water.The synergy of these two materials led to the increase on the oil concentration in the liquid,which in turn enhanced the collision of emulsified oil droplets to aggregate into large ones in the emulsion and resulted separation from the water.Based on these findings,an aggregation-induced demulsification process was proposed to explain the above phenomenon,and the mechanism was confirmed by studying the distribution of oil droplets in emulsion with a controlled separation degree.
