| After billions of years of evolution,animals and plants in nature through a series of wonderful evolution,in the interaction with the complex natural environment,have the ability to fully adapt to nature,so they can make the best response to the changes of the natural environment.The special ability of animal and plant surface comes from multi-level micro-nano tructure and chemical composition,and gets inspiration from nature and imitates it.Bionics arises at the historic moment under this background,and it is gradually becoming an interdisciplinary central scientific research field.In this paper,two kinds of Janus structures with different properties were prepared by combining laser micro-nano manufacturing technology and surface wettability principle of bionic manufacturing,so as to carry out the research and application of Janus structure in the field of underwater gas transport: first,two sides of Janus(superhydrophobic/superhydrophilic)aluminum foil with asymmetric wettability were obtained by means of laser micro / nano manufacturing and low surface energy reagent modification.Janus aluminum foil is placed in a self-made aerator to produce uniform ultra-fine bubbles for high-performance aeration,which can be used for wastewater treatment and water aeration.Secondly,the reverse buoyancy and positive buoyancy three-dimensional self-driven transport of underwater bubbles on its surface can be realized by processing Janus(hydrophobic/superhydrophobic)aluminum foil with conical structure.Finally,it is used as an electrode in the experiment of electrolytic salt water to achieve the purpose of in-situ generation,directional transport and collection of hydrogen and chlorine on the surface of Janus aluminum foil,which can be used for underwater multi-dimensional transportation and gas collection.The main contents of this paper are as follows:(1)This paper introduces the prototypes of different surface wettability in nature,the related mechanism of surface wettability,the source and existing preparation methods of Janus structure,the wide application of Janus structure,combined with the research basis of bubbles in the field of gas manipulation such as aeration and three-dimensional transport of underwater bubbles,and points out the significance and content of this research.(2)The characteristics of nanosecond laser processing system and micro-nano processing,the interaction between nanosecond laser and metal surface,and the effects of laser power and sweep spacing on the wettability of aluminum foil surface are introduced.The results show that the surface of the rough surface shows super-hydrophilic characteristics by increasing the laser power and reducing the sweep spacing,and after fluorination treatment,the superhydrophilic surface can be directly transformed into a super-hydrophobic surface.(3)Using nanosecond laser microstructure preparation and low surface energy reagent-assisted modification,Janus(superhydrophobic/superhydrophilic)aluminum foil with uniform micropore array was constructed.The hydrophilic surface of repelling gas is beneficial to reduce the bubble size and accelerate the separation of bubbles from the surface of aluminum foil.On the other hand,the hydrophobic surface prevents water from infiltrating into the aeration chamber and greatly reduces the mass transfer resistance.Uniform small bubble aeration for a long time is realized by adjusting the diameter and spacing of micropores.The results show that when the surface of aerated porous aluminum foil is hydrophilic,the pore diameter is smaller,and the pore spacing is larger than the bubble diameter,the smaller the bubble diameter is,the longer the retention time in aqueous solution is.Through the color experiment of smelling musk deer vanillol blue solution,it was proved that Janus(superhydrophilic/superhydrophobic)aluminum foil significantly increased the rate of gas dissolution.(4)Janus(hydrophobic/superhydrophobic)conical aluminum foil was prepared by nanosecond laser processing combined with low surface energy reagent modification.It is found that(hydrophobic/superhydrophobic)Janus conical aluminum foil has the ability of reverse buoyancy and buoyancy along the hydrophobic side to the superhydrophobic side.In addition,the transmission efficiency and bubble volume capacity of aluminum foil are higher by adjusting the aperture,taper and length of aluminum foil.The results show that the larger the pore diameter is,the faster the penetration velocity is in the direction of reverse and positive buoyancy.By reducing the angle of the cone angle and prolonging the length of the aluminum foil,the larger the holding volume of the bubble on the surface of the aluminum foil is.Finally,using Janus conical aluminum foil as electrode,through the construction of electrolytic salt water integrated system,the combined action of surface energy gradient and shape gradient can realize the integrated process of automatic generation,self-driving transmission and automatic collection of hydrogen and chlorine on both sides of aluminum foil.The research results of this paper are helpful to improve the further application of Janus structure in the field of underwater aeration and underwater gas self-driven three-dimensional transportation,and a new preparation method with low manufacturing cost,simple and controllable is adopted.Figure[48] table[1] reference[74]... |
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