Nanometer Tio2 Crystal Shape Control And Rare Earth Doping On The Properties Of Electrorheological Effect

Electrorheological fluid’s viscosity is changing rapidly in the process of asserting or removing external electricity field. This property has make electrorheological fluid become the one of the most noticeable smart materials. However, a normal electrorheological fluid often has the problems of low suspending stability, small system shear force, and long response time. Therefore, designing new electrorheological fluid system, which is anti-subsidence with an easily changing phase and high intensity response, is an indispensable path to promote the in-depth real application for electrorheological fluid.Titanium dioxide has the characteristics of high dielectric constant, low conductivity and easy to synthesis, attracting wide attention in the preparation of high performance electrorheological fluid. This paper did research on titanium dioxide electrorheological fluid, by preparing crystal controllable nano titanium dioxide through solvothermal method and through adding rare earth element to modify the performance hoping to further improve the response to electric field. We carefully studied the preparation conditions that can influence crystallite and shape of titanium dioxide, which includes the types of solvents, types and amounts of the added elements. Then coupling agent was used for surface modification and polymer nano-composition was also employed to polish and modify the composed titanium dioxide nano-particles for the purpose of electrorheological fluid’s better suspension stability. Based on this, the author symmetrically characterized the electrorheological fluid’s suspension stability and its electrorheological behavior, and established the relationship between the electrorheological fluid performance and the influencing factors (the crystal pattern and particle shapes, types and amounts of the added elements, and the method for particle surface modification). The main results and conclusions are shown as below:1. Nano titanium dioxide’s crystal pattern control and the added rare earth elements:Nano titanium dioxide power was successfully made using the solventthermal method and its crystal pattern was influenced by the solvent composition. When chloroform is used as solvent, the resulted titanium dioxide has the rutile shape. When the solvent is methanol, the shape is antase. And if the solvent is a mixture of ethanol and acetone, the products will be a mixture of rutile and antase shape. Although solvents temperature and reaction time do not have a significant influence over titanium dioxide power crystal composition, they have a higher influence on the particle size and shape. To be more specific, with the increasing of reaction temperature and reaction time, the particle size is also growing. With sol-gel method coupled with hydrothermal method to prepare the rare earth elements, the obtained titanium dioxide does not have a changing crystal pattern, instead it has a distorted crystal lattice.2. Nano titanium dioxide surface modification and electrorheological fluid preparation: silane coupling agent KH-570were used to make the surface modification for titanium dioxide. By asserting carbon-carbon double bond on the surface and then dispersing titanium dioxide in Vinyl silicone oil to have grafting reaction, dispersion ability in silane coupling agent was improved. When the modified rate is0.5, it has the best dispersion effects. In addition, nanocomposite with uniform surface to adsorb titanium dioxide is produced by the electrostatic force between the positive charge on the surface of the titanium dioxide particles and the negative charge on the surface of the composite.3. Nano titanium dioxide electrorheological property research:After the subsiding stability test, nano titanium dioxide whose surface was modified by coupling agent has grafting reaction in the Vinyl silicone oil dispersion solvent and developed the intertwined three-dimension mesh structure, which significantly improves the subsiding stability of electrorheological fluid as to the level of no subsiding even after long period settlement. The dielectric properties test shows that the types and amounts of rare earth element ions have significant influence over dielectric properties. The higher the content of dispersed nano particles, the higher the dielectric constant of the electrorheological fluid. With the overall effects of electrorheological fluid’s settlement performance improvement and adding the rare earth element ions to improve the nano particle’s dielectric performance, the nano titanium oxide electrorheological fluid’s electrorheological performance has significantly increased.