Ceramic capillary membrane has received much attention due to its relatively high pack density and favorable mechanical strength.However,it is difficult to prepare capillary membrane on its thin support by a dip-coati...Ceramic capillary membrane has received much attention due to its relatively high pack density and favorable mechanical strength.However,it is difficult to prepare capillary membrane on its thin support by a dip-coating method.In this study,alumina microfiltration membranes were prepared on the inner surface of alumina capillary support(outer diameter 4 mm,inner diameter 2.5 mm)by a dip-coating method.Scanning electron microscopy(SEM)observation,gas bubble pressure(GBP)method and membrane permeation test were carried out to evaluate membrane performance.Two major effects in preparation of crack-free membrane,capillary filtration and film-coating,upon the thin support were studied.The as-prepared crack-free membrane presents a narrow pore size distribution,a mean pore size of about 0.6μm and a high pure water flux of 86000 L·m -2 ·h -1 ·MPa.It is proved that the membrane thickness should be sufficiently large to overcome the defects of support surface,but it is only one of the prerequisites for the formation of crack-free membrane.Furthermore,it is demonstrated that the capillary filtration effect is greatly restricted for thin capillary support with the dip-coating method and the film-coating effect plays a crucial role in the formation of crack-free membrane.展开更多
With properties of complete degradation and favorable mechanical behavior, Mg and its alloys are regarded as the next generation medical metal materials. However, fast degradation and poor surface biocompatibility hin...With properties of complete degradation and favorable mechanical behavior, Mg and its alloys are regarded as the next generation medical metal materials. However, fast degradation and poor surface biocompatibility hinder their clinical applications. Inspired by the ＂petal effect＂, we successfully constructed a superhydrophobic and highly adhesive coating on pure Mg via a simple hydrothermal treatment in a solution containing sodium oleate. The superhydrophobicity of the fabricated coating results from its flake-like micro-nanostructure and the low-surface-energy oleate group. Water droplet on the superhydrophobic coating cannot roll off even when the sample is turned upside down, owing to the sealed air-pockets and the van der Waals’ attraction at the solidliquid interface, indicating a highly adhesive force. The chemical and mechanical stability of the superhydrophobic coating were measured. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements suggest enhanced corrosion resistance of the as-prepared sample.Furthermore, cell cytotoxicity, migration and adhesion data of human umbilical vein endothelial cells（HUVECs） reveal an improved cytocompatibility of the modified surface. Finally,hemolysis assay and platelet adhesion assay suggest an improved hemocompatibility. It is believed that the facile and low-cost method can expand the new application of superhydrophobic surface with highly adhesive on Mg in biomedical fields.展开更多
基金Supported by the National High Technology Research and Development Program of China （2007AA030303）, the National Basic Research Program of China （2009CB623400） and the National Natural Science Foundation of China （20776067）.
文摘Ceramic capillary membrane has received much attention due to its relatively high pack density and favorable mechanical strength.However,it is difficult to prepare capillary membrane on its thin support by a dip-coating method.In this study,alumina microfiltration membranes were prepared on the inner surface of alumina capillary support(outer diameter 4 mm,inner diameter 2.5 mm)by a dip-coating method.Scanning electron microscopy(SEM)observation,gas bubble pressure(GBP)method and membrane permeation test were carried out to evaluate membrane performance.Two major effects in preparation of crack-free membrane,capillary filtration and film-coating,upon the thin support were studied.The as-prepared crack-free membrane presents a narrow pore size distribution,a mean pore size of about 0.6μm and a high pure water flux of 86000 L·m -2 ·h -1 ·MPa.It is proved that the membrane thickness should be sufficiently large to overcome the defects of support surface,but it is only one of the prerequisites for the formation of crack-free membrane.Furthermore,it is demonstrated that the capillary filtration effect is greatly restricted for thin capillary support with the dip-coating method and the film-coating effect plays a crucial role in the formation of crack-free membrane.
基金financially supported by the Distinguished Young Scholars of China(51525207)the National Natural Science Foundation of China(31570973)+1 种基金the National Key Research and Development Program of China(2016YFC1100604)Shanghai Committee of Science and Technology,China(15441904900)
文摘With properties of complete degradation and favorable mechanical behavior, Mg and its alloys are regarded as the next generation medical metal materials. However, fast degradation and poor surface biocompatibility hinder their clinical applications. Inspired by the ＂petal effect＂, we successfully constructed a superhydrophobic and highly adhesive coating on pure Mg via a simple hydrothermal treatment in a solution containing sodium oleate. The superhydrophobicity of the fabricated coating results from its flake-like micro-nanostructure and the low-surface-energy oleate group. Water droplet on the superhydrophobic coating cannot roll off even when the sample is turned upside down, owing to the sealed air-pockets and the van der Waals’ attraction at the solidliquid interface, indicating a highly adhesive force. The chemical and mechanical stability of the superhydrophobic coating were measured. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements suggest enhanced corrosion resistance of the as-prepared sample.Furthermore, cell cytotoxicity, migration and adhesion data of human umbilical vein endothelial cells（HUVECs） reveal an improved cytocompatibility of the modified surface. Finally,hemolysis assay and platelet adhesion assay suggest an improved hemocompatibility. It is believed that the facile and low-cost method can expand the new application of superhydrophobic surface with highly adhesive on Mg in biomedical fields.
