2012/05/19 by Philippe Brunet, Brunet, Philippe
Engineering · Pharmacology, Toxicology and Pharmaceutics · Physics and Astronomy · #Advancements in Transdermal Drug Delivery #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Heat Transfer #Nanomaterials and Printing Technologies #Soft Condensed Matter (cond-mat.soft) #cond-mat.soft #physics.flu-dyn
paper · pdf · doi:10.48550/arxiv.1205.4366
9 pages
arxiv created 2012/05/19 · openalex publication_date 2012/05/19 · arxiv updated 2012/05/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the size and shape of the final deposit obtained when a drop with colloidal particles has dried on a super-hydrophobic surface made of micro-posts. As expected, most of the particles lie inside a circular area, which radius roughly corresponds to the Laplace pressure threshold for liquid impalement inside the structure (Cassie-Wenzel transition), inducing a coffee-stain deposit due to contact-line pinning. Less expected is the observation of tiny deposits on top of posts in the area external to the main ring, despite the low macroscopic liquid/solid friction. Experiments are carried out varying the concentration in particles and initial volume of drops, in order to determine the influence of these parameters on the size distribution of deposits. A microscopic insight of the tiny deposits is proposed, based on recent experiments of non-volatile liquid sliding drops.