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Nonmonotonic contactless manipulation of binary droplets via sensing of localized vapor sources on pristine substrates

Droplet motion on surfaces influences phenomena as diverse as microfluidic liquid handling, printing technology, and energy harvesting. Typically, droplets are set in motion by inducing energy gradients on a substrate or flow on their free surface. Current configurations for controllable droplet man...

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Detalles Bibliográficos
Autores principales: Malinowski, Robert, Parkin, Ivan P., Volpe, Giorgio
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Association for the Advancement of Science 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7556999/
https://www.ncbi.nlm.nih.gov/pubmed/32998894
http://dx.doi.org/10.1126/sciadv.aba3636
Descripción
Sumario:Droplet motion on surfaces influences phenomena as diverse as microfluidic liquid handling, printing technology, and energy harvesting. Typically, droplets are set in motion by inducing energy gradients on a substrate or flow on their free surface. Current configurations for controllable droplet manipulation have limited applicability as they rely on carefully tailored wettability gradients and/or bespoke substrates. Here, we demonstrate the nonmonotonic contactless long-range manipulation of binary droplets on pristine substrates due to the sensing of localized water vapor sources. The droplet-source system presents an unexpected off-centered equilibrium position. We capture the underlying mechanism behind this symmetry breaking with a simplified model based on the full two-dimensional functional form of the surface tension gradient induced by the source on the droplet’s free surface. This insight on the transport mechanism enables us to demonstrate its versatility for applications by printing, aligning, and reacting materials controllably in space and time on pristine substrates.