Study On Preparations And Motions Of Dual-Driven Micromotor

Micromotors are colloidal particles which can convert the energy in the surrounding environment into their own mechanical energy,thus realizing self-driving motions.In recent years,the research of micromotors has made great progress,and micromotors have shown a wide application prospect in the fields of biosensor,drug delivery,sewage treatment and so on.However,there are still many difficulties in preparing micromotors,such as complicated procedures,expensive equipment and low yield.In addition,the existing preparation methods can only synthesize the micromotors with a single driving mode,and there is still a lack of preparation of micromotors with multiple driving modes.These greatly hinder the further development of micromotors,and thereby it is urgent to develop new synthesis technology to achieve simple and effective preparation of micromotors..In this thesis,we propose a simple and effective method to prepare monodisperse organic-inorganic composite Janus micromotors.First,polymer(polystyrene,PS)particles are suspended in the mixture of the deionized water and the good solvent of polymer particles.According to the principle of "similar solubility",polymer particles will be softened by the solvent.The softened polymer particles and excess activated inorganic nanoparticles(such as AgCl,TiO2,ZnO,Fe2O3,etc.)are then mixed by a rotary incubator,which makes the polymer particles contact with the inorganic particles.Due to the wetting effect of the softened polymer,the organic and inorganic components fuse together to form micromotors,with the inorganic particles acting as motor engines.More importantly,by using this method,we can combine the magnetic response and chemical response to prepare the dual drive micromotor by replacing the common polymer particles with the magnetic polymer particles(Fe3O4 core-PS shell).Compared with other methods,our method has many advantages,such as simple procedures,low-cost equipment,scale up potential and more material options.In addition,we have developed another simple and universal method to prepare dual drive micromotors with both magnetic response and chemical stimulation response.First,the magnetic polystyrene particles(PS core,Fe3O4 shell)are treated with a good solvent of the polymer.Based on the principle of phase separation and the principle of surface energy minimization,the PS in the magnetic shell is extruded to form a bulge,thereby obtaining snowman-like particles.After that,NH2 functional group was modified on the surface of Fe3O4 nanoparticles by adding silane coupling agent,and then chloroplatinic acid was added to form a complex between platinum ion and amino group according to the rules of soft and hard acid-base and the principle of complex stability.Finally,the dual drive micromotor of Fe3O4/Pt Complex was obtained by reducing platinum ion.This method can be used to produce dual drive micromotors in a simple and low-cost way.In addition,on this basis,using the method of the first work,we can continue to deal with this dual drive micromotor,and obtain a variety of externally driven micromotors.