ZnO-TiO_(2)异质微米马达系统的光控重构变形行为

Light-controlled Reconfigurations of ZnO-TiO_(2) Heterogeneous Micromotor System

主要研究了ZnO-TiO_(2)异质微米马达系统的近红外光诱导对流原位定点构建方法和紫外光控重构变形行为。在近红外光诱导对流作用下,分散的TiO_(2)微米粒子于红外光斑中的ZnO微米针处原位聚集形成ZnO-TiO_(2)异质微米马达系统。当施加紫外斜光时,无规自驱动的ZnO微米针因其受光面发生光腐蚀反应释放离子产物(Zn^(2+))而产生基于电解质扩散泳的正趋光定向运动,TiO_(2)微米粒子因其受光面发生光催化H_(2)O_(2)分解反应释放出分子产物(O_(2))而产生基于非电解质扩散泳的负趋光性定向运动。因此,通过动态调节控制入射光的方向,可以实时控制强正趋光性ZnO微米马达的运动方向和运动轨迹,从而对弱负趋光性TiO_(2)集群进行复杂切割(如直线、圆形和多次切割),实现对分裂子群的大小、形态和数量以及整个系统重构变形的复杂操控。本研究将为微米马达集群的形态控制和智能多功能微米马达集群系统的构建提供新策略,推动其在动态微图案化和微纳米组装加工方面的应用。

We investigated in-situ construction of the ZnO-TiO_(2)heterogeneous micromotor system by the near-infrared(NIR)light-induced convections and its UV-controlled reconfigurations.Under the near-infrared light-induced convections,the dispersed TiO_(2)microparticles gather around the ZnO microneedle in the center of the NIR light spot to form a ZnO-TiO_(2)heterogeneous micromotor system.When oblique UV light is applied,the randomly self-propelled ZnO microneedle experiences photo-corrosions on the light-irradiated surface to release ionic products(Zn^(2+)),resulting in directional positive phototactic motion based on electrolyte diffusiophoresis.In contrast,due to the photocatalytic decomposition reaction of H_(2)O_(2)on the illuminated side,TiO_(2)microparticles release molecular products(O_(2))and produce directional negative phototactic motion based on non-electrolyte diffusiophoresis.Therefore,by dynamically adjusting the direction of the incident light,the motion directions and trajectories of ZnO micromotor with strong positive phototaxis can be controlled in real time,thus performing complex cutting(such as straight,circular,and multiple cutting)on the weak negative phototactic TiO_(2)swarm to achieve complex manipulation of split subgroups in the size,shape,and numbers,as well as system reconfigurations.This study will provide new strategies for the morphological control of micromotor swarms and the construction of intelligent multi-functional micromotor swarm systems,promoting their applications in dynamic micro-patterning and micro/nano assembly and fabrication.