title: Fixing colloidal motions at water/air interface with micrometer scale resolution.
abstract: Fast colloidal motions driven by surface tension gradient are created in a thin water layer. Unlike using solid boundaries to limit the colloidal flow, our work relaxes this condition by directly placing bulk fluid next to an open air environment. When the colloidal flow along the air/water interface is interfered with stationary objects, repetitive semicircular motions, that is, micro eddy, are frequently observed in domains as small as 2 μm. We assign the capillary convection between the liquid next to the air and that from the bulk as the driving force for the observed motions. Relationships among the maximum speed, temperature gradient, and thickness of the liquid layer are experimentally investigated and numerically analyzed. Our results could inspire future designs of micromechanical motors or fluidic mixing in a miniature device.
authors: Department of Mechanical and Materials Engineering, University of Nebraska, Lincoln, Nebraska 68588, United States.
authors: Ziguang
authors: Z
authors: Chen
authors: Lorin
authors: L
authors: Baird
authors: Li
authors: L
authors: Tan
mesh_terms: D000388:Air / Q000032:analysis*; D003102:Colloids; D013500:Surface Tension; D014867:Water / Q000737:chemistry*
chemical_list: D003102:Colloids; D014867:Water