In situ viscometry by optical trapping interferometry
In situ viscometry by optical trapping interferometry
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DOI：
10.1063/1.3020713
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发表时间：
2008-11-03
影响因子：
4
通讯作者：
Jeney, Sylvia
中科院分区：
文献类型：
--
作者：
Guzman, Camilo;Flyvbjerg, Henrik;Jeney, Sylvia
我们通过跟踪受到小振荡流影响的光学捕获微球的热波动来演示定量原位粘度测量。测量到的球体位置的功率谱密度在流动的驱动频率处显示出特征峰，当以相同频率下的热功率谱密度单位测量时，该特征峰与粘度成简单比例。测量结果在不同的水-甘油混合物以及甘油梯度中进行了验证，其中不使用溶液的先验知识来确定甘油浓度。
We demonstrate quantitative in situ viscosity measurements by tracking the thermal fluctuations of an optically trapped microsphere subjected to a small oscillatory flow. The measured power spectral density of the sphere's positions displays a characteristic peak at the driving frequency of the flow, which is simply proportional to the viscosity, when measured in units of the thermal power spectral density at the same frequency. Measurements are validated on different water-glycerol mixtures, as well as in a glycerol gradient, where no a priori knowledge of the solution is used to determine the glycerol concentration.