Study On Silica Based Core-shell Nanocomposite Electrorheological Materials

Electrorheological(ER)materials,as a new type of intelligent material with fast response to electric field,have shown great application prospect in electric control devices and received more and more attention and applications in recent years.Electrorheological fluids usually consist of insulating carriers and polarizable particles,which are randomly dispersed and exhibit liquid-like properties when no electric field is applied.When the electric field is applied,the liquid like in the ER fluid is rapidly converted to solid like,forming a chain or column structure along the direction of the electric field.When the electric field is removed,the above process is reversible,so it has extensive practical significance in the research of shock absorption structure and braking.Among many inorganic materials,silica(SiO₂)has the advantages of simple synthesis method,uniform morphology and size and easy adjustment and control.It has been widely used in the field of Electrorheological.However,SiO₂ itself has defects such as low dielectric constant,low polarization ability and weak conductivity.As an ER material alone,it will lead to low shear stress and can't improve the ER effect.Therefore,based on silica,this paper uses silica as a shell through the core-shell structure to improve the ER efficiency of the composite.The following are the experimental contents and results:1:Firstly,the hollow tubular H₂Ti₂O₅nanoparticles were prepared by hydrothermal method.Taking H₂Ti₂O₅ nanotubes as template,SiO₂ was coated on the H₂Ti₂O₅ nanotubes during the preparation process by controlled hydrolysis method to form H₂Ti₂O₅@SiO₂ core-shell nanoparticles.The core-shell structure reduces the leakage current density of H₂Ti₂O₅ nanotubes and improves the interparticle interface polarization ability.The one-dimensional hollow structure also greatly improves the electrorheological properties.By adjusting the amount of reactants and reaction time to control the morphology and size,the electrorheological properties are greatly improved,the ER efficiency can reach 160.8.2:Based on the binary combination,a ternary complex core-shell structure was designed.Honeycomb-shaped H₂Ti₂O₅@MoS₂ composite particles were prepared by hydrothermal method,and then SiO₂ was coated on the surface of H₂Ti₂O₅@MoS₂composite particles by controlled hydrolysis method.The special two-dimensional honeycomb structure of H₂Ti₂O₅@MoS₂ provided a large number of growth sites for the SiO₂ shell,which made it easier to be coated.Due to the unique structure of H₂Ti₂O₅nano whiskers,the advantages of MoS₂'s multilayer structure and SiO₂-controlled conductivity,as well as the core-shell structure,H₂Ti₂O₅@MoS₂@SiO₂ ER studies show excellent performance,the ER efficiency can reach 103.4.3:Polyaniline@molybdenum disulfide composite nanoparticles with special morphology were prepared by two-step method.Firstly,polyaniline nanoparticles were prepared and collected under the condition of ice bath in the wet state.Then,molybdenum disulfide was coated on the surface of polyaniline precursor by hydrothermal method to form PANI@MoS₂ composite particles.The composite material combines the core-shell structure and the porous properties of two-dimensional material.The suspension with nano-particles as the dispersed phase has good suspension stability.Nanoparticles were modified by surfactants to become very effective ER suspensions.In addition,we measured the electrorheological properties of PANI@MoS₂ composite particle nanocomposites under different electric field intensity in controlled shear rate(CSR)mode,and found that there is a good ER effect,and the ER efficiency can reach 82.0.