气泡推进型中空Janus微球运动特性的实验研究  

Experimental study on the characteristic motion of bubble propelled hollow Janus microspheres

作　　者：张静[1] 郑旭[2] 王雷磊 崔海航[1] 李战华[2] 

机构地区：[1]西安建筑科技大学环境与市政工程学院,西安710055 [2]中国科学院力学研究所,北京100190

出　　处：《实验流体力学》2017年第2期61-66,共6页Journal of Experiments in Fluid Mechanics

基　　金：国家自然科学基金(11572335;11272322;11672358);陕西省教育厅重点实验室项目(15JS045)

摘　　要：本文通过Pt-SiO_2型(铂-二氧化硅型)中空Janus微球在低浓度2%~4%H_2O_2溶液中的气泡驱动实验,观察到在每个气泡生长-溃灭周期内,Janus微球的运动呈现3个特征阶段,分别为自扩散泳、气泡生长和气泡溃灭。其中气泡溃灭阶段微球在射流驱动下的推进速度可达每秒几十毫米,比前2个阶段的平均速度大2~3个数量级。实验观察到气泡生长阶段其半径与时间存在Rb^t1/3和Rb^t1/2两种标度率。由于气泡在Janus微球催化剂表面(Pt侧)的生长点偏离对称轴位置,Janus微球的运动轨迹呈圆周形。随H_2O_2溶液浓度的增加,还可以进一步提高Janus微球的运动速度。此研究不仅定量分析了Janus微球的运动特性,而且为实际应用中提高Janus双面微马达的运动速度和能量利用率提供了参考依据。This paper studies the bubble propelled motion of Pt-SiO2 hollow Janus micro- spheres in H2O2solutions （concentrations between 2% to 4%）. Three typical stages have been observed in every period of the bubble growth-collapse, which are selLdiffusiophoresis, bubble growth and bubble collapse. At thebubble collapse stage, the speed propelled by a mierojet can reach tens of millimeter per second, and it is about 2 or 3 orders of magnitude higher than the speed in the other two stages. In the experiment, two scaling laws between the bubble radius and the elapsed time during the bubble growth stage are observed： Rb~ t1/3 and Rb~ t1/2 Because the bubble growing point at the Janus microsphere＇s Pt side deviates from the axisymmetric point, the trajectory of the Janus microsphere is nearly a circle. With the increase of the H2O2 concentra- tions, the speed of the Janus microspheres can be enhanced. This study not only quantifies the characteristic motion of Janus microspheres, but also provides valuable information for improving the speed and energy utilization of Janus micromotors in practical application.

关 键 词：中空Janus微球 气泡驱动 气泡溃灭 

分 类 号：O353.4[理学—流体力学] O353.5[理学—力学]