The Fabrication Of Magnetically Responsive And Anisotropic Solid Slippery Surface And Their Applications In Droplet/Bubble Transportation

The transport of fluids is ubiquitous in nature and closely related to human production and life.In order to achieve smart control and directional transport of fluids,researchers have developed a series of biomimetic functional surfaces materials by learning from nature.These surfaces can realize intelligent control and directional transport of fluids to some extent.However,how to realize the intelligent control of liquid and gas on the same surface and how to achieve stably directional transport of fluids in a complex environment are still urgent issues to be solved.Therefore,in this thesis,we developed a magnetically responsive amphibious slippery gel surface and an anisotropic solid slippery surface for realizing the controllable motion of droplets/bubbles and directional transport of droplets.The controllable motion of bubbles in aqueous environment plays an important role in gas sweetening,mineral flotation and the collection of methane gas under seawater.In order to manipulate bubbles underwater and smartly control the motion of droplets in air and bubbles underwater on the same surface,an amphibious slippery surfaces were fabricated by using magnetically responsive soft poly(dimethylsiloxane)doped with iron powder,followed by infusion of silicone oil.The slippery gel surface showed outstanding stability both in air and underwater because the lubricant was firmly locked in the threedimensional gel network.The surface exhibited strong affinity toward bubbles underwater,which facilitated the controllable movement of bubbles.The sliding behavior of liquid droplets and bubbles can be smartly controlled by the external magnetic field,originating from the adjusting morphology of the slippery gel surface.The surface can be used as a microreactor for fixed-point chemical reaction and bubbles mixture,showing the potential applications in microfluidics,microreactors,directional liquid/bubble transport,and other related fields.The lubricants of the traditional slippery surfaces,which are mostly liquid state,are easy to migrate and loss during the process of use,and contaminate the nearby surfaces upon contacting with other surfaces.Additionally,the hydrophobic contaminants deposited on the traditional slippery surfaces are usually self-cleaned by using organic solvents,which increase the costs and are harmful to environment.Fortunately,the solid slippery surfaces show excellent stability.The lubricants cannot be lost and the nearby surfaces cannot be contaminated after contacting with other surfaces.Herein,Based on the coorperation of copy paper and paraffin wax,an anisotropic solid slippery surface with directional micro-grooves structure was fabricated from simple replica technique.The surface exhibited excellent stability and outstanding acid and alkali corrosion resistance.It is demonstrated that the surface has good anisotropic sliding behavior for liquid droplets with different surface tension.It also showed an excellent restoration capability upon physical damage and can be restored back to the initial state.More importantly,both of hydrophilic and hydrophobic contaminants deposited on the anisotropic solid slippery surface can be self-cleaned by using only water droplets,which reduced the environment pollution.This type of self-cleaning surface shows potential applications in the fields of directional liquid transport and microfluidics.