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

本项目的目的是通过光学镊子捕获的纳米颗粒的交流电泳迁移率来测量软物质中的三维结构和局部力学响应。我们在商用荧光显微镜的基础上研制了双光束光钳，并成功地对软物质中的胶体粒子进行了纳米级的操作。通过反射光的位置可以检测到被捕获粒子的位置。该系统减少了颗粒的布朗运动，大大提高了测量精度。此外，利用该系统还可以进行以下研究：(1)用线钳直接测量胶体相互作用；(2)直接测量向列相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.