磁珠@TiO2微米马达的正趋光性运动行为  

Positive phototaxis behavior of magnetic bead@TiO2 micromotors

作　　者：王玉宽 谢琦 许蕾蕾[1] 罗明 牟方志[1] WANG Yukuan;XIE Qi;XU Leilei;LUO Ming;MOU Fangzhi(State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,International School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学材料复合新技术国家重点实验室,材料科学与工程国际化示范学院,湖北武汉430070

出　　处：《中国粉体技术》2020年第4期9-14,共6页China Powder Science and Technology

基　　金：国家自然科学基金项目,编号:21875175,21975195,21705123;湖北省自然科学基金项目:编号:2019CFA048。

摘　　要：为了研究基于核壳结构磁珠@TiO2(MB@TiO2)微米马达的正趋光性运动行为,利用超声辅助溶胶凝胶法在磁珠表面包覆薄TiO2层,制备核壳结构的MB@TiO2微米马达;采用扫描电子显微镜、透射电子显微镜、光学显微镜对MB@TiO2微米马达的结构、形貌和运动性能进行表征。结果表明:MB@TiO2微米马达呈核壳结构,其受光面和背光面在紫外光照射下发生的非对称光催化反应,使水介质中的H2O2光催化分解产物,在微米马达两侧不均匀分布形成浓度梯度;由于H+产物浓度梯度产生指向光源的扩散泳力占主导作用,MB@TiO2微米马达呈现出朝向光源的正趋光性运动行为;正趋光性运动行为使得MB@TiO2微米马达可以克服重力轻易翻越障碍,实现在复杂地形环境中航行或在远离基板的体相水中运动;结合TiO2壳层的光催化活性和MB内核的磁响应性,MB@TiO2微米马达未来有望作为易磁分离的“游动”光催化剂应用于环境治理。In order to study the positive phototaxis behavior of core-shell structured magnetic bead@TiO2(MB@TiO2)micromotors,the surface of magnetic beads was coated with a thin TiO2 layer using ultrasonic-assisted sol-gel method to prepare core-shell structured [e-mail] structure,morphology,and motion behaviors of MB@TiO2micromotors were characterized by scanning electron microscope(SEM),transmission electron microscope(TEM),and optical microscope.The results show that the MB@TiO2 micromotors have a core-shell structure.The asymmetric photocatalytic reactions between the light-irradiated surface and the shadowed surface of the MB@TiO2 micromotors under ultraviolet light is used to make the photocatalytic products of hydrogen peroxide unevenly distribute on both sides of the micromotor to form a concentration gradient.The diffusiophoretic force produced by the H+concentration gradient pointing to the light source predominates,and thus the MB@TiO2 micromotors exhibit positive phototaxis toward the light source.Due to its positive phototaxis behavior,the MB@TiO2 micromotors can easily overcome gravity to climb obstacles and swim in complex terrain or bulk water far from the substrate.In addition,combining the photocatalytic activity of the TiO2 shell and the magnetic responseof the MB core,the MB@TiO2 micromotors are expected to be used as the“swimming”photocatalystsin environmental remediation witheasy magnetic separation in the future.

关 键 词：微纳米马达 磁珠 趋光性 光催化 

分 类 号：TB34[一般工业技术—材料科学与工程]