The Ordered Structure Of The Surface Of The Membrane Was Induced By Solvent Evaporation

The membranes with ordered surface structure have important application potential in the fields of template materials,superhydrophobic medium and cell adhesion.How to form a controlled and ordered structure on the surface of membrane has attractedmuchconcern.In this paper,the forming mechanism and key factors of ordered structure on the surface of the membrane were studied systematically.The ordered structure on the membrane surface induced by the method of solvent evaporation,and combined with surface segregation and template effect.By optimizing and adjusting the process conditions,the membrane surface with regular patterns or ordered micropores was successful fabreicated,which is of great significance for enriching ordered membrane construction methods.In this paper,polystyrene(PS)and polymethylmethacrylate(PMMA)were used as the membrane materials,the patterned membranes with three-dimensional topography were successfully prepared on the surface of the membrane by methods of blending,and the surface segregation occurred during the membrane formation.The results showed that the compatibility of the polymers,polymer-to-polymer ratio and the volatility of dissolution play an important role on the pattern of membrane surface.At the same time,different influences are considered on the surface structure of the membrane,such as the ratio of the two polymers in the casting solution,the concentration of the casting solution,the membrane thickness and the temperature of the solvent evaporation.The structure and composition of the membrane surface were studied by means of SEM,IR,XPS,and discussed the evolving regulation of the structure on the membrane surface.The results show that the ratio of the two polymers has a great influence on the surface morphology of the membrane.When the casting solution is a single component,the membrane surface can't form a pattern structure.When the ratio of PS/PMMA is 6:1,the pattern structure of the membrane surface is the most regular and smaller size,in the range of 0.2-0.3?m;The pattern structure of the membrane surface is vary with the solvent evaporation temperature.The concentration of the polymer,thickness of the membrane and solvent evaporation temperature have great influence on the surface morphology of the membrane.When the concentration of the polymer is 10%,the film thickness is 0?mm and the solvent evaporation temperature was 30 ?,membranes with three-dimensional topography will be successfully prepared.XPS,EDS and contact angle analysis are used to analyze the surface and bottom surfaces of the memranes.It was found that there were more polystyrene on the positive surface of the membrane,and more the poly(methyl methacrylate)on the bottom surface.The results show that the surface segregation behavior of the membranes in the preparation of the membranes is proved.At the same time,the ordered structure were successfully prepared by adding template molecules,andpolystyrene(PS)and polysulfone(PSf)as the membrane materials in this paper.The structure and composition of the membrane surface were studied by means of scanning electron microscopy(SEM).The results showed that the micro-poreon the membrane surface was closely related to the template molecule content and the solvent volatility.The other factors are considered systemically to control the pattern of the membrane surface.The results showed that the most ordered structure are prepared on PS and PSf membrane when the template molecule content is 2.4%and 2%.The concentration of the polymer has influence on the membrane surface,the most ordered structure are prepared on PS and PSf membrane when the template molecule content is 10%and 7%.The pore structure of the membrane surface became more regular when inceasing the temperature of the solvent evaporation,the most uniform structure are formed at 50?.