Colloidal attraction induced by a temperature gradient

Autor:	Di Leonardo, R., Ianni, F., Ruocco, G.
Rok vydání:	2008
Předmět:	Condensed Matter - Soft Condensed Matter Condensed Matter - Materials Science
Druh dokumentu:	Working Paper
Popis:	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. Comment: 4 pages, 4 figures
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/0811.3188 Zobrazit plný text záznamu View this record from Arxiv