Dielectrophoresis Of Tio < Sub > 2 < / Sub > Research On The Positioning And Preparation Of Inorganic Nanoparticles Such As Control

This paper summarizes development of the dielectrophoresis technology and its application in all fields. Furthermore, it introduces the progress and advantages of DEP technology in research for inorganic particles in detail. Moreover, it reports the methods of separation manipulation and preparation TiO2at the present time. Then the theory of DEP is elaborated.In the optimized dielectrophoresis macro-device, DEP responces and DEP trapping separation of the rare earth and other inorganic oxide particles are investigated. In addition, The influence of TiO2crystal growth is discussed by Combining sol-gel processing and colloidal chemistry method with dielectrophoresis for the first time.Then, dielectrophoresis micro-array electrode chips and a microscopic static state device are manufactured. Based on the above, the manipulation and position of inorganic oxide particle are studied.The results as follows are got by a series of experiments:1. Research of DEP trap of inorganic particles in macroscopic conditions(1) The phenomena of DEP:Negative DEP of hollow microsphere, La2O3, CeO2and Dy2O3particles is observed in the experiments.(2) Voltage: The nunber of inorganic particles trapped by DEP increased with increase of applied voltage.(3) DEP time:More inorganic particles are trapped to the electrodes by DEP with the increase of DEP time. (4) Velocity:The DEP capture effect is getting better when the the velocity is lower.(5)Concentration:The DEP capture effect is getting better when the initial concentration of suspension is higher.There are obvious dielectric response differences between different inorganic oxide particle.So It is possible to separate oxide particles by controlling the voltage, velocity and so on.2. Preparation of TiO2using DEP/sol-gel(1)Combining sol-gel processing with DEP for the first time, DEP may trigger the formation of TiO2crystals from gel.(2) The particle size of TiO2increases firstly, then decreases with the rise of voltage of direct current.(3)Particle size increases with the rise of the voltage at given frequency; and particle size decreases with the rise of the frequency when applying alternating current given voltage with.(4)The different proportion of crystalline are controlled through controlling some conditions.(5)In certain non-uniform electric field conditions, uniform particle size of TiO2can be prepared.3.Preparation of TiO2using DEP/sol(1)Combining sol processing with DEP for the first time, DEP may trigger the formation of TiO2crystals from sol. (2)The nanoTiO2which was prepared by DEP/sol method is mainly anatase crystal and contains a small amount of brookite.(3)Calcination can make the particle size of TiO2increase and all brookite disappear.(4)The particle size of TiO2before calcination increases firstly with the voltage rise, then decreases and at last the increases.The particle size of TiO2after calcination increases firstly with the voltage rise, then decreases. Maximum value of partical size is among2--3V. Therefore partical size of TiO2can be controlled by DEP technology.(5)DEP may trigger the TiO2crystal growth along the direction perpendicular to the electrode4.The research of DEP manipulation and position of inorganic particles at microscopic static state(1)Thedeveloped DEP array chips are suitable to investigate Dielectric corresponding. Negative DEP is observed both in the experiments of hollow microsphere and Silica microspheres. The experiments of Titanium dioxide take place positiveDEP.(2)The trap areas of oxide particles are changed when frequency changes.The positioning of oxide particles can be realized by changing the frequency. (3)DEP time has influence on enrichment effect of nano TiO2.The enrichment effect increases firstly and then decreases With the increase of electrophoretic time.(4)Electrode gap has influence on the positioning of oxide particles. When electrode distance increasing, hollow microsphere can be enriched between the electrode gaps.(5)The electrode shape has influence on the positioning of TiO2. In specific electrode shape, Connection of nanoTiO2is realized successfully between two electrode gaps.