Flow-controlled growth in Langmuir monolayers
نویسندگان
چکیده
We propose a hydrodynamic mechanism, based on the Marangoni flow, to describe growth instabilities of liquid-condensed islands in the supercooled liquid-expanded phase of two-dimensional Langmuir monolayers. This Marangoni instability is intrinsic to Langmuir monolayers and is not controlled by the expulsion of chemical impurities from the liquid-condensed phase. The hydrodynamic transport of the insoluble surfactants is shown to overwhelm passive diffusion and to provide a mechanism for fingering instabilities. The model can explain the observations by Brewster-angle microscopy of ramified liquidcondensed islands in monolayers that do not contain the fluorescent dye impurities, which are normally believed to be responsible for Langmuir-film growth instabilities. PACS. 05.70.Np Interface and surface thermodynamics – 68.18.Jk Phase transitions – 47.20.Dr Surfacetension-driven instability
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