Fabrication And Properties Of Special Wettability Materials Based On Stainless Steel

Wettability is one of the important properties of a solid surface,which is mainly determined by the microscopic geometry and chemical composition of the solid surface.Stainless steel is a common metal material that is widely used in everyday life and industrial applications.This dissertation is based on stainless steel and is devoted to the development of the preparation method of special wettability materials with simple process,low cost and excellent performance,and further studies on its related performance.It provides innovative ideas and experimental guidance for the preparation and application of advanced special wettability materials based on stainless steel.The main works are shown as follows:（1）A facile cycle-etching approach is used to fabricate micro/nano-scale binary structures on 304 stainless steel surfaces.The effect of the times of cycle-etching on the morphology and roughness of samples is investigated.After PDES modification,the wettability of samples is characterized and found that the stainless steel surface obtained by the third cycle-etching becomes super-repellent toward water and peanut oil.Since SS-E₃-M surface without the last ultrasonic etching to remove unstable nano-flowers on the surface,as a result,we employ the SS-E₃-C-M surface as the target sample.The Potentiodynamic polarization curves and electrochemical impedance spectroscopy（EIS）show that the superamphiphobic SS-E₃-C-M surface has excellent corrosion resistance.（2）One-step chemical etching method is used to fabricate uniformly distributed micro/nano-scale pits on 316L stainless steel mesh surfaces by changing the etching time.After stearic acid modification,superhydrophobic/superoleophilic stainless steel mesh surface is obtained with a water contact angle（WCA）of 162°,a water sliding angle（WSA）of 0°and an oil contact angle（OCA）of 0°.The surface morphology,composition and wettability of the original stainless steel mesh and superhydrophobic/superoleophilic stainless steel mesh are characterized,which shows that the chemical etching and stearic acid modification play an important role in preparing superhydrophobic/superoleophilic stainless steel mesh.The superhydrophobic/superoleophilic stainless steel mesh is investigated for corrosion resistance and its application in oil-water separation.The experimental results show that the superhydrophobic/superoleophilic stainless steel mesh has good corrosion resistance,wide applicability to oil-water separation and excellent recyclability.（3）One-step vapor deposition of polydimethylsiloxane is used to fabricate two types of meshesbychangingthetemperatureofvapordeposition.Weemploy superhydrophobic/superoleophilic M-350 in air and superhydrophilic M-500 in air as the target samples to be analyzed,respectively.The morphology,composition and wettability of M-350 and M-500 are characterized to illustrate the effects of different vapor deposition temperatures on the morphology and composition of the surfaces,as well as the crucial role of surface morphology and composition in the preparation of stainless steel meshes with different wettability.The contact angle test reveals that M-350 has underoil superhydrophobicity and M-500 has underwater superoleophobicity.Oil-water separation experiments show that we can selectively use the underoil superhydrophobic M-350 and the underwater superoleophobic M-500 to separate oil-water mixtures according to the density of the oil and water.These two types of meshes have wide applicability to oil-water separation and excellent recyclability,and still take effects under severe environmental situation.