Local mechanical property of complex fluids studied by laser trap ac electorphoretic

本计画的目的是利用光镊捕捉奈米粒子的交流电泳迁移率来量测软物质的三维结构与局部力学响应。我们在商用荧光显微镜的基础上研制了双光束光镊，并成功地对软物质中的胶体粒子进行了纳米尺度的操作。捕获粒子的位置可以通过反射光的位置来检测。在该系统中，粒子的布朗运动被减小，测量精度得到了很大的提高，并可用于以下研究：（1）线镊法直接测量胶体相互作用，（2）直接测量无水溶剂中的胶体相互作用，（3）直接测量单个囊泡的粘弹性。

The aim of this project is to measure 3-dimensional structure and local mechanical response in soft matters by ac electrophoretic mobility of nano-sized particles trapped by optical tweezers. We have developed dual beam optical tweezers base on a commercial fluorescent microscope and succeeded in operating a colloidal particle in soft matter with nano-scales. The position of the trapped particle can be detected by the position of reflected light. In this system, Brownian motion of particles is reduced and the accuracy of measurement has been greatly improved.Moreover the following study is able to do with the developed system; (1)direct measurement of colloidal interaction by line tweezers, (2)direct measurement of colloidal interaction in nematic solvent, (3)direct measurement of viscoelasticity of a single vesicle.