Two grafting methods, i.e. solution grafting and pre-adsorbing, are introduced to covalently immobilizehydrophilic polymers on segmented polyurethane (SPU) to modify its hydrophilicity and to improve its cell compatib...Two grafting methods, i.e. solution grafting and pre-adsorbing, are introduced to covalently immobilizehydrophilic polymers on segmented polyurethane (SPU) to modify its hydrophilicity and to improve its cell compatibility.Solution grafting results in higher degree of grafting and rougher surface morphology. Cell culture evaluation demonstratesthat the modified membranes thus obtained are disadvantageous to the endothelial cell (ECs) growth probably because thehydrophilic groups on the surface are over-crowded. However, pre-absorbing grafting generates lower degree of grafting,which is detected and confirmed by ATR-FTIR spectra and water conted angle. Scanning electron microscopic (SEM)measurement shows that the latter method produces a plane and smooth morphology, which is similar to the SPU controlsample controlled. When grafting with lower monomer concentration, ECs could grow on SPU-g-PHEA [poly(2-hydroxyethyl acrylate)], SPU-g-PAAm (polyacrylamide), SPU-g-PDMA [poly(2-(dimethylamino)ethyl methacrylate)] orquatemized SPU-g-PDMA surface with elongated cell shapes. Hence, the cell compatibility of SPU is improved and a usefulmethod to construct a cell compatible layer on the polymer surface has been developed.展开更多
The interaction between Sn and passivated stainless steel was evaluated through an easy chromaticity approach.The microstructure of Fe-Sn intermetallics(IMCs)was observed,and their growth was inspected at differenf ti...The interaction between Sn and passivated stainless steel was evaluated through an easy chromaticity approach.The microstructure of Fe-Sn intermetallics(IMCs)was observed,and their growth was inspected at differenf time after the in teract io n.The oxide film on stainless steel exposed in air locally delayed IMC growth,and the chemically passivated film protected stainless steel from Fe-Sn compound formation.To investigate the interaction mechanism,the integrity of passivated films grown on stainless steel was evaluated by chromogenic inspection.The interaction extern was related to colour measurement a*.Results indicated that the measured value of a*from the inspection decreased with the increasing exposure time,and a minimum a*value was found in chemically passivated samples.The tendency of the colour measureme was consistent with the effect of passive film on IMC growth.The in terfacial reaction of passivated stainless steel with Sn was illustrated based on the integrity of the passive films.展开更多
基金This project was supported by the National Natural Science Foundation of China (No. 59803006), the Major State Basic Research Program of China (G1999054305) and the Natural Science Foundation of Zhejiang Province.
文摘Two grafting methods, i.e. solution grafting and pre-adsorbing, are introduced to covalently immobilizehydrophilic polymers on segmented polyurethane (SPU) to modify its hydrophilicity and to improve its cell compatibility.Solution grafting results in higher degree of grafting and rougher surface morphology. Cell culture evaluation demonstratesthat the modified membranes thus obtained are disadvantageous to the endothelial cell (ECs) growth probably because thehydrophilic groups on the surface are over-crowded. However, pre-absorbing grafting generates lower degree of grafting,which is detected and confirmed by ATR-FTIR spectra and water conted angle. Scanning electron microscopic (SEM)measurement shows that the latter method produces a plane and smooth morphology, which is similar to the SPU controlsample controlled. When grafting with lower monomer concentration, ECs could grow on SPU-g-PHEA [poly(2-hydroxyethyl acrylate)], SPU-g-PAAm (polyacrylamide), SPU-g-PDMA [poly(2-(dimethylamino)ethyl methacrylate)] orquatemized SPU-g-PDMA surface with elongated cell shapes. Hence, the cell compatibility of SPU is improved and a usefulmethod to construct a cell compatible layer on the polymer surface has been developed.
基金the National Natural Science Foundation of China(NSFC No.51571051)Science and Technology Research Fund of Liaoning Province,Department of Education(Nos.L2016008,L2017LQN026)+1 种基金Doctor Research Startup Fund of Liaoning Province(No.201601336)Scientific Research Cultivation Fund of LSHU(No.2016PY-024).
文摘The interaction between Sn and passivated stainless steel was evaluated through an easy chromaticity approach.The microstructure of Fe-Sn intermetallics(IMCs)was observed,and their growth was inspected at differenf time after the in teract io n.The oxide film on stainless steel exposed in air locally delayed IMC growth,and the chemically passivated film protected stainless steel from Fe-Sn compound formation.To investigate the interaction mechanism,the integrity of passivated films grown on stainless steel was evaluated by chromogenic inspection.The interaction extern was related to colour measurement a*.Results indicated that the measured value of a*from the inspection decreased with the increasing exposure time,and a minimum a*value was found in chemically passivated samples.The tendency of the colour measureme was consistent with the effect of passive film on IMC growth.The in terfacial reaction of passivated stainless steel with Sn was illustrated based on the integrity of the passive films.
