Water Drop Evaporation on Mushroom-like Superhydrophobic Surfaces: Temperature Effects

Author(s)

do Nascimento, Rodney Marcelo ^{[1, 2]} ; Cottin-Bizonne, Cecile ^[1] ; Pirat, Christophe ^[1] ; Ramos, Stella M. M. ^[1]

Affiliation

^[1] Univ Lyon 1, UMRS306, Inst Lumiere Mat, F-69622 Villeurbanne - France

^[2] Univ Sao Paulo, Sao Carlos Inst Phys, POB 369, BR-13566590 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Langmuir; v. 32, n. 8, p. 2005-2009, MAR 1 2016.
• Web of Science Citations: 16

Abstract

We report on experiments of drop evaporation on heated superhydrophobic surfaces decorated with micrometer-sized mushroom-like pillars. We analyze the influence of two parameters on the evaporation dynamics: the solid-liquid fraction and the substrate temperature, ranging between 30 and 80 degrees C. In the different configurations investigated, the drop evaporation appears to be controlled by the contact line dynamics (pinned or moving). The experimental results show that (i) in the pinned regime, the depinning angles increase with decreasing contact fraction and the substrate heating promotes the contact line depinning and (ii) in the moving regime, the droplet motion is described by periodic stick slip events and contact-angle oscillations. These features are highly smoothed at the highest temperatures, with two possible mechanisms suggested to explain such a behavior, a reduction in the elasticity of the triple line and a decrease in the depinning energy barriers. For all surfaces, the observed remarkable stability of the ``fakir{''} state to the temperature is attributed to the re-entrant micropillar curvature that prevents surface imbibition. (AU)

• FAPESP's process: 13/21970-8 - Development of biomaterial from the incorporation of calcium phosphates in latex structures to order application as controlled release device
• Grantee: Rodney Marcelo do Nascimento
• Support Opportunities: Scholarships in Brazil - Post-Doctoral