Cross-sectional tracking of particle motion in evaporating drops: flow fields and interfacial accumulation.

ABSTRACT: The lack of an effective technique for three-dimensional flow visualization has limited experimental exploration of the "coffee ring effect" to the two-dimensional, top-down viewpoint. In this report, high-speed, cross-sectional imaging of the flow fields was obtained using optical coherence tomography to track particle motion in an evaporating colloidal water drop. This approach enables z-dimensional mapping of primary and secondary flow fields and changes in these fields over time. These sectional images show that 1 μm diameter polystyrene particles have a highly nonuniform vertical distribution with particles accumulating at both the air-water interface and the water-glass interface during drop evaporation. Particle density and relative humidity are shown to influence interfacial entrap

SUBMITTER: Trantum JR 

PROVIDER: S-EPMC4915780 | biostudies-literature | 2013 May

REPOSITORIES: biostudies-literature