基于动态光散射技术研究群体自驱动Janus颗粒的增强型布朗运动行为  

Enhanced Brownian motion of the group self-propellant Janus particles based on dynamic light scattering technique

作　　者：刘金豪 王雷磊 崔海航[1] 张鸿雁[1] 陈力[1] Jinhao Liu;Leilei Wang;Halhang Cui;Hongyan Zhang;Li Chen(School of Environment and Municipal Engineering,Xi＇an University of Architecture and Technology,Xi＇an 710055,China;Research Institute of Membrane Separation Technology of Shaanxi Province,Xi＇an 710055,China)

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]陕西省膜分离技术研究院,西安710055

出　　处：《科学通报》2018年第28期2994-3001,共8页Chinese Science Bulletin

基　　金：国家自然科学基金(11447133;11602187);陕西省教育厅专项科研计划(15JK1385);陕西省重点科技创新团队计划(2017KCT-19-01);西部绿色建筑国家重点实验室培育基地自主科研项目资助

摘　　要：自驱动Janus颗粒是两侧具有不同性质并可进行自驱运动的非均质颗粒的统称.本文以标称直径为1μm的Pt-SiO_2型自驱动Janus颗粒(以下简称Janus颗粒)为研究对象,利用动态光散射技术(dynamic light scattering, DLS)研究了其在纯水及不同浓度H2O2溶液中的运动行为.实验结果表明:群体Janus颗粒在H2O2溶液中的运动行为表现为增强型布朗运动.随着H_2O_2溶液浓度的增加,DLS测得群体Janus颗粒的有效扩散系数增大且都大于其在纯水中布朗运动时的扩散系数,且其弛豫时间逐渐减小.此外,根据DLS测得的自相关函数反演算推导得到了群体Janus颗粒在极短时间间隔内的均方位移.其结果表明:在相同观测时间间隔下,随着H_2O_2溶液浓度的增大,均方位移增加;在相同浓度的H_2O_2溶液中,随着观测时间间隔的增加,均方位移增加.最后,分析了单粒子追踪技术(single particle tracking,SPT)与DLS两种方法用于研究Janus颗粒运动行为的特点与区别,并指出观测时间间隔是影响DLS和SPT两种方法实验结果的关键因素.Janus particles collectively refer to the non-uniform particles with different properties on two sides. Due to their asym- metry, asymmetric physical or chemical reactions shall be performed by the functionalized Janus particles by using ＂fuel＂ in the environment, thereby forming the gradient fields of different physical quantities, such as concentration, electric field or light intensity on both sides of the particles, so the autonomous motion shall be carried on by using the asymmetrical momentum distribution formed by the gradient. At present, the main methods to study the self-propulsion of Janus particles include single particle tracking （SPT） and dynamic light scattering （DLS）. In this paper, the movement behavior of Pt-SiO2 Janus particles with a nominal diameter of 1 μm in pure water and in H2O2 solutions was analyzed, whose results were compared with that of the SPT. The experimental results show that the movement behavior of group Janus particles in H2O2 solution showed the enhanced Brownian motion. With the increase of the concentration of H2O2 solution, the effective diffusion coefficient of group Janus particles was increased by using the DLS method, which was less than the effective diffusion coefficient of single Janus particles measured by using the SPT method. In addition, in this paper, according to the inverse calculation of the self-correlation function measured by DLS, the mean square dis- placement of group Janus particles in the extremely short time interval was obtained. The results showed that at the same observation time interval, the mean square displacement shall be increased with the density enhancement of the H2O2 solutions, while in the H2O2 solutions with the same density, the mean square displacement shall be increased with the increase of the observation time interval. Finally, the characteristics and differences of SPT and DLS methods to study the Janus particle motion behavior were analyzed. It is shown that the observation interval is the key factor among the meas

关 键 词：Janus颗粒 有效扩散系数 动态光散射技术 增强型布朗运动 单粒子追踪法 

分 类 号：O552.1[理学—热学与物质分子运动论]