Preparation Of Titanium Oxide-based Nanocomposite Particles And Study On Its Electrorheological Properties

Electrorheological fluid(ER Fluid)is an emerging smart material composed of insulating liquid and dispersed phase particles.As a type of two-phase fluid,it has a unique ER effect.When an electric field is applied to the ER suspension,the disperse phase solid particles with chaotic distribution can be instantaneously polarized,so that the particles attract each other to form a neat chain structure,and this process is reversible.Because it can accurately affect the yield strength change through the change of the electric field,to achieve the state we need,it has broad development prospects in my country's aviation flight,machinery industry,braking equipment and other fields.In recent years,more and more types of materials have been used in electrorheological fields,such as metal oxides,conductive polymers,and inorganic semiconductors.Because TiO₂ has high dielectric constant,simple preparation,low cost,non-toxic and non-polluting and other advantages,so there is more research on it at present.However,through actual tests,it is found that the ER effect of TiO₂ is poor:the yield stress is low and cannot meet the needs of industrial production,it is easy to settle,and the performance is greatly affected by temperature.Therefore,we use TiO₂ as the substrate,composite other materials or change the morphology of TiO₂ to design and prepare electrorheological fluid to improve its ER performance.The following are the main experimental contents and results:(1)The hollow structure reduces the density while increasing the specific surface area of the particles,which can enhance its electrorheological properties to a certain extent.Using a mixed solution of ethanol and acetone as the solvent,the eggshell TiO₂hollow structure was synthesized by one-step template-free solvothermal method.By changing the reaction time variable and combining with SEM and TEM characterization methods,the eggshell TiO₂ hollow spheres were explored.Formation mechanism.Finally,the electrorheological fluid obtained by fully mixing eggshell TiO₂hollow spheres with silicone oil exhibits a strong electrorheological effect under the action of an electric field.(2)The double-layer hollow structure not only combines the strong polarization ability of the core-shell structure,but also contains the advantages of the hollow structure.Because of eggshell TiO₂ hollow spheres,a mixed solution of ethanol and deionized water is used as a solvent,and the eggshell TiO₂ hollow spheres are coated with silica by the St(?)ber hydrolysis method to achieve a double-layer hollow structure.The electrorheological test shows that the addition of silicon oxide greatly reduces the leakage current density and greatly improves the ER efficiency.(3)The combination of small-size silicon-titanium molecular sieve TS-1 and high-dielectric constant titanium oxide not only utilizes the unique morphology of TS-1 but also enhances its ER performance.First,use the nano-scale silicon-titanium molecular sieve(TS-1)prepared by the hydrothermal method as a template,use a mixed solution of ethanol and deionized water as the solvent,and continuously adjust the addition amount of tetrabutyl titanate(TBT)to change the titanium oxide The thickness of the coating layer finally obtains core-shell structure TS-1/titanium oxide nanocomposite particles with a suitable coating layer thickness.Disperse TS-1/TiO₂ core-shell structure nanocomposite particles in silicone oil,form an electrorheological fluid with a mass ratio of 10%after mixing,and conduct ER performance test on it.It is found that the effect of electric field makes the ER suspension show a strong Electrorheological property.The dielectric performance test proves that the improvement of the dielectric performance promotes the enhancement of the electrorheological performance.(4)The combination of rod-shaped C₃N₄ and TiO₂ nanoparticles enhances the anisotropy of the composite particles and at the same time increases their dielectric constant.Using urea and melamine as the solvent in deionized water,the columnar C₃N₄was successfully prepared by the solvothermal method,and then the TiO₂was loaded on the columnar C₃N₄ by the sol-gel method.The silicone oil is mixed with the prepared sample at a weight ratio of 10%to obtain an ER suspension.Through testing,it is found that the addition of TiO₂ increases the dielectric constant of the ER suspension compared to C₃N₄without TiO₂.The improvement in dielectric properties leads to enhanced electrorheological properties.