微波辅助合成微纳米多级结构二氧化钛颗粒及其电流变性能

The traditional approaches to prepare multilevel micro/nanostructured particles have two obvious drawbacks, which are troublesome multistep procedure and long reaction time in preparation. Microwave-assisted synthesis is generally much faster than the conventional way. In this project, we used microwave-assisted methods to prepare multilevel micro/nanostructured TiO2 and TiO2 composite particles for electrorheological materials. The influences of different reaction conditions including the power of microwave, the radiation time, the reaction temperature, stirring rate, polarization of solvent and the ability of reactants to absorb microwave on the morphology and interior structure of hierarchical microsphere are studied systematically. The growth mechanism of micro/nanostructured particles in the microwave field and the techniques to prepare micro/nanostructured particles with interior structure controllable by microwave-assisted methods are explored. Inorganic ER materials based on doped TiO2 particles of micron size showed excellent ER activities. In this project, the ER effect, dielectric properties, and sedimentation of the multilevel micro/nanostructured TiO2 composite ER fluids are investigated. Especially, we investigated the contribution of multilevel micro/nanostructure to anti-sedimentation, interfacial polarization and particle-particle interaction of the electrorheological fluids. Based on the experimental results, micro/nanostructured TiO2 composite particles with special interior structure are designed to reduce their density and the attractive force between them. The anti-sedimentation TiO2 composite particles with excellent ER activities are designed and synthesized by microwave-assisted methods. The problem of sedimentation of inorganic ER fluids based on particles of micron size will be eliminated.

本项目针对传统化学方法制备微纳米多级结构材料的工序多、耗时长的问题，基于微波效应能够大幅加快反应速率的特点，拟通过微波辅助合成法制备微纳米多级结构TiO2及其复合颗粒。通过研究微波功率、反应温度、辐射时间、搅拌速度、反应物的吸波性能、溶剂极性等多个参数对颗粒微观形貌与结构的影响，探索微波效应对微观结构的影响机制，掌握精确可控、高效快速的微纳多级结构无机颗粒的微波辅助合成技术。TiO2基复合颗粒是一类重要的无机电流变材料，本项目拟研究微纳多级结构TiO2基复合颗粒电流变液的抗沉降稳定性、介电性能及电流变效应，探索微纳多级结构对颗粒的悬浮稳定性、颗粒极化和颗粒间相互作用的影响规律，通过在微观尺度上控制材料结构来降低颗粒表观密度、改善颗粒间的相互作用，有针对性地设计特定结构的微纳米颗粒，制备出抗沉降且电流变性能优良的微纳多级结构TiO2基电流变材料，从而解决传统无机电流变液易沉降的难题。

二氧化钛是一种性能优良的半导体材料，微波合成法是一种以快速、高效、节能、环保为显著特点的新型合成方法。本项目针对传统化学方法制备晶态的微纳米二氧化钛及稀土掺杂氧化钛复合颗粒的工序多、耗时长、需高温处理等问题，研究了快速制备不同形貌、不同晶型的二氧化钛以及稀土掺杂二氧化钛的微波合成工艺，并测试了颗粒的电流变性能。取得的主要研究成果有：. 1）研究了溶剂、反应物、微波功率、反应温度、辐射时间等多个参数对产物的晶型、粒径、微观形貌与结构的影响规律，探索出锐钛矿型二氧化钛微球、金红石型海胆状二氧化钛颗粒及混合晶型二氧化钛微纳米多级结构颗粒的新微波合成工艺。. 2）设计了铈（Ce）、钐(Sm)、铥(Tm)、铽(Tb)等不同稀土元素掺杂的二氧化钛微球的微波合成工艺，成功地实现采用微波法快速合成粒径、掺杂浓度可调控的稀土掺杂二氧化钛微球。. 3）研究了几种典型的微波合成二氧化钛颗粒的电流变性能，证实其与传统化学法制得的颗粒的电流变效应相一致。. 本项目探索出快速、高效、可控地制备不同晶型与形貌的氧化钛及稀土掺杂氧化钛微纳米颗粒新工艺，为无机电流变液材料及其他新型材料的研究提供了可靠的材料制备方法。作为第一标注发表SCI论文2篇论文，与其他项目合作发表第二标注SCI论文2篇；项目组成员参加国内会议2人次；依托该项目培养硕士研究生3名，合作培养博士研究生3名。