Entropic attraction and repulsion in binary colloids probed with a line optical tweezer
Entropic attraction and repulsion in binary colloids probed with a line optical tweezer
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DOI：
10.1103/physrevlett.82.4352
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发表时间：
1999-05-24
影响因子：
8.6
通讯作者：
Yodh, AG
中科院分区：
文献类型：
--
作者：
Crocker, JC;Matteo, JA;Yodh, AG
使用线扫描光学镊子直接测量了两个微米大小的胶体球体在由小得多的胶体球体组成的流体中产生的长程熵力。这项新技术使我们能够测量具有亚k(B)T能量和15 nm空间分辨率的势的泛函形式。在最低的小球浓度下，电势是单调吸引的，而在较高的浓度下，由于小球的液体结构，观察到了振荡电势。令人惊讶的是，在较高的浓度下，大球体很少聚集在一起，这表明了一种仅使用熵来稳定悬浮液的新方法。[S0031-9007(99)09246-7]。
The long-range entropic forces that arise between two micrometer-sized colloidal spheres in a fluid of much smaller colloidal spheres were directly measured using a line-scanned optical tweezer. This new technique allowed us to measure the functional form of the potential with sub-k(B)T energy and 15 nm spatial resolution. At the lowest small sphere concentrations, the potential was monotonically attractive, while at higher concentrations an oscillatory potential was observed, due to the liquid structure of the small spheres. Surprisingly, the large spheres came together only rarely at the higher concentrations, suggesting a new means for stabilizing suspensions using entropy alone. [S0031-9007(99)09246-7].