Optical tweezers: wideband microrheology
Optical tweezers: wideband microrheology
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DOI：
10.1088/2040-8978/13/4/044022
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发表时间：
2011-04-01
影响因子：
2.1
通讯作者：
Tassieri, Manlio
中科院分区：
文献类型：
--
作者：
Preece, Daryl;Warren, Rebecca;Tassieri, Manlio
微流变学是流变学的一个分支，其原理与传统的体流变学相同，但其工作范围是微米尺度和微升体积。相反，当使用光镊来测量复杂流体的粘弹性时，结果要么限于材料的高频响应，丢弃与低频行为相关的重要信息，要么通过使用不同技术进行的低频测量来补充，通常不会在结果集之间呈现明显一致的重叠区域。我们提出了一个简单的实验程序进行微观流变测量在最宽的频率范围内可能与光镊。一个广义朗之万方程是用来与频率相关的模量的复杂流体的探针粒子的时间依赖性的轨迹，因为它翻转之间的两个光学陷阱，交替开关和关闭。
Microrheology is a branch of rheology having the same principles as conventional bulk rheology, but working on micron length scales and microlitre volumes.Optical tweezers have been successfully used with Newtonian fluids for rheological purposes such as determining fluid viscosity. Conversely, when optical tweezers are used to measure the viscoelastic properties of complex fluids the results are either limited to the material's high-frequency response, discarding important information related to the low-frequency behaviour, or they are supplemented by low-frequency measurements performed with different techniques, often without presenting an overlapping region of clear agreement between the sets of results. We present a simple experimental procedure to perform microrheological measurements over the widest frequency range possible with optical tweezers. A generalized Langevin equation is used to relate the frequency-dependent moduli of the complex fluid to the time-dependent trajectory of a probe particle as it flips between two optical traps that alternately switch on and off.