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arXiv 0811.3188cond-mat.softcond-mat.mtrl-sci
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温度梯度引起的胶体引力

Colloidal attraction induced by a temperature gradient

R. Di Leonardo, F. Ianni, G. Ruocco

摘要:

胶体晶体在光子晶体技术等应用研究和统计力学的基础研究中具有极其重要的意义。长程吸引相互作用,如毛细作用力,可以驱动这种介观有序结构的自发组装。然而,长程引力在胶体界是非常罕见的。在这里,我们报告了一种新的强大的和远程的吸引力诱导的热梯度存在的墙壁。打开和关闭热梯度,我们可以快速和可逆地形成稳定的六方二维晶体。我们发现,所观察到的吸引力是流体动力学的性质,并产生热诱导颗粒表面上的滑移流。我们使用光镊直接测量力法,并将其与基于Marangoni力驱动的Stokes流的分析预测进行比较。

英文摘要:

Colloidal crystals are of extreme importance for applied research, such as photonic crystals technology, and for fundamental studies in statistical mechanics. Long range attractive interactions, such as capillary forces, can drive the spontaneous assembly of such mesoscopic ordered structures. However long range attractive forces are very rare in the colloidal realm. Here we report a novel strong and long ranged attraction induced by a thermal gradient in the presence of a wall. Switching on and off the thermal gradient we can rapidly and reversibly form stable hexagonal 2D crystals. We show that the observed attraction is hydrodynamic in nature and arises from thermal induced slip flow on particle surfaces. We used optical tweezers to directly measure the force law and compare it to an analytic prediction based on Stokes flow driven by Marangoni forces.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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