Manipulation of Colloids by a Nonequilibrium Depletion Force in a Temperature Gradient
Manipulation of Colloids by a Nonequilibrium Depletion Force in a Temperature Gradient
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DOI：
10.1103/physrevlett.102.208301
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发表时间：
2009-05-22
影响因子：
8.6
通讯作者：
Sano, Masaki
中科院分区：
文献类型：
--
作者：
Jiang, Hong-Ren;Wada, Hirofumi;Sano, Masaki
实验研究了温度梯度下聚合物溶液中胶体的非平衡分布。聚焦激光引起的局部温度的轻微升高将胶体推向热区域，导致胶体的捕获，而不管其自身的热泳性质。的放大捕获的胶体密度与聚合物浓度的测量，并定量地解释了流体动力学理论。吸引力的起源是由聚合物的热泳作用维持的不均匀聚合物分布驱动的胶体迁移。这些结果显示了如何控制胶体的热泳性能。
The nonequilibrium distribution of colloids in a polymer solution under a temperature gradient is studied experimentally. A slight increase of local temperature by a focused laser drives the colloids towards the hot region, resulting in the trapping of the colloids irrespective of their own thermophoretic properties. An amplification of the trapped colloid density with the polymer concentration is measured, and is quantitatively explained by hydrodynamic theory. The origin of the attraction is a migration of colloids driven by a nonuniform polymer distribution sustained by the polymer's thermophoresis. These results show how to control the thermophoretic properties of colloids.