The effect of the orientation and the height of periodic sub-micrometric texturing on dropwise condensation

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:526

Article

Pionnier, Nicolas¹  Vera, Julie¹  Contraires, Elise¹  Benayoun, Stephane¹  Berger, Remi²  Valette, Stephane¹ 

[1] Univ Lyon, Lab Tribol & Dynam Systemes, Ecole Cent Lyon, UMR 5513, F-69131 Ecully, France

[2] PSA Peugeot Citroen, E78943, Velizy Villacoublay, France

关键词: Dropwise condensation;    Oriented structures;    Ripples;    Wettabiliry;    Polycarbonate;   

DOI  :  10.1016/j.jcis.2018.04.043

来源: Elsevier

【 摘 要 】

Controlling condensation conditions by surface topography is of prime interest. The aim of this work is to investigate the behavior of water droplets condensing on oriented sub-micrometric structures representing ripples with wavelengths around 800 nm. Droplet behavior was studied on different ripples heights and on untextured surfaces. It was specifically looked at how the presence of ripples creates geometrical confinement, and how that influences the deformation and the orientation of single droplets. Results show that the condensed droplets follow the orientation of textured features, especially with high structures height (150 nm). This is shown by the decreasing of droplet roundness with ripples height. The relative number of circular droplets (roundness near to 1) is around 0.6 for 70 nm high ripples and decrease to around 0.2 for 150 nm high ripples. The corresponding relative number on untextured surface is around 0.5. A mechanism, based on droplets pinning and hysteresis, is proposed to explain the influence of the ripples orientation in a vertical plane, onto the droplet deformation during coalescence step. Finally, the presence of ripples is shown to barely impact breath figure dynamics. Number of droplets and mean droplet radius for the textured and untextured surfaces present a comparable evolution. (C) 2018 Elsevier Inc. All rights reserved.

【 授权许可】

Free