Controllable Underwater Weting Behavior On The Shape Memory Epoxy Resin Array

Wettability is an important physical property of solid surfaces which is controlled by both microstructure and chemical composition.So far,control of the surface wettability is mainly rely on changing surface microstructure or chemistry,to realize the coordination control of the two factors to obtain the surface with smart tunability in wettability,especially in the water phase,is still a problem.In this work,by combining the shape memory effect of the shape memory effect and the oxygen plasma treatment technology,we realized the synergetic regulation of the microstructure and chemical composition on the surface,and the intelligent degree of the wetting control in water was significantly improved.Firstly,a temperature-sensing shape memory epoxy microarray with different spacing of 10 ?m is prepared by template method.The shape memory performance and the variation of surface chemical composition of the prepared microarray were carried out.The experimental results show that the shape fixation rate and the response rate of the microarray are 97.67% and 97.62%,respectively,indicating excellent shape memory performances of the surface.After the oxygen plasma treatment,the percentage of oxygen atoms increased from 18.54% to 35.70%,indicating that the hydrophilic oxygen-containing groups were enriched on the surface.After heating in air,the surface oxygen content decreased to 17.24%,means that heating treatment can help recovery of the surface chemical composition.By making use of the shape memory property of the microarray and the controllable surface chemistry,we realized the reversible regulation of the underwater oil wettability.It is found that the oil contact angle on the surface underwater could be reversibly changed between 0° and 163° as the microstructure and chemical composition of the surface are changed.At the same time,the mechanism of microstructure change and surface chemical change of the materials prepared were also analyzed and studied.The results show that the dynamic controllable microstructure can endow the surface with different magnified effect on the wetting performance;and the reversible change of of surface chemistry would give the reversible change the undereater oleophobicity/oleophilicity on the surface.The smart controllability of the surface wettability in ascribed to the combining effect between the above two points.In order to realize the intelligent tunable wettability of gas in water on the solid surface,a microarray with a height of 30 ?m and an aspect ratio of 3:1 was prepared by the similar method.In order to solve the problem of decreasing the response rate of microarray caused by excessive aspect ratio,the ratio of benzenediamine and n-octylamine in the curing agent was changed to 2:3(molar ratio)to improve the modulus and the recovery rate reached 98.37%.It was found that the contact angle of the underwater gas on the surface of the material could be reversibly changed between the superaerophilicity(about 2°)and the superaerophobicity(about 150°)through reversibly changing the surface chemical composition and microstructure.Results indicate that excellent controllability of underwater gas wetting perfrmance can be achieved on our surface,which lays the foundation for the further study on the wettability regulation of the underwater air.