Rational design of static wetting on roughness-engineered heterogeneous surfaces
Martí Balaguer, Gerard (Universitat Autònoma de Barcelona. Departament de Química)
Serra-Peralta, Marc (Institut de Microelectrònica de Barcelona)
Rius, Gemma (Institut de Microelectrònica de Barcelona)

Data:	2024
Resum:	Surface roughness and chemical composition are crucial in controlling the static wetting properties of surfaces. Here, conventional surface structuring methods used in Si microfabrication are used as a reference to analyze the impact of precisely engineered surface roughness. The static wettability of rough chemically heterogeneous surfaces is experimentally studied through contact angle measurements and compared against computational simulations to categorize the wetting behavior of water droplets. Heterogeneous samples are observed to already show significant dependence on the surface fraction covered by each material. Furthermore, owing to the presence of a resist layer on top of the Si pillars, intermediate states between the Wenzel (W) and Cassie-Baxter (CB) models are observed. Consistent with these models, we find that local chemical modifications of microstructured surfaces are crucial for controlling their surface wettability properties. Additionally, a comparison of equivalent microstructures made of Si or polydimethylsiloxane (PDMS) reveals the quantitative impact of the hydrophilic/hydrophobic nature of the material on the evolution of the wetting properties with increasing roughness factors. While Si surfaces behave according to the W model, PDMS surfaces show intermediate wetting states at significantly lower roughness levels. Bubbles trapped beneath water droplets demonstrate the existence of intermediate states that cannot be defined by either the W or CB models. By combining experimental results with finite element simulations, we not only demonstrate wettability control through specific roughness and chemical modifications but also provide insight into how these parameters interact to accurately predict and adjust static wetting properties.
Ajuts:	Agencia Estatal de Investigación RyC-2026-21412 Agencia Estatal de Investigación CEX2023-001397-M Agencia Estatal de Investigación FPU019/04322
Nota:	Altres ajuts: acords transformatius de la UAB
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Microfabrication ; Etching ; Photolithography ; Finite-element analysis ; Liquid solid interfaces ; Hydrophobic effect
Publicat a:	Physics of fluids (Woodbury, N.Y. ), Vol. 36, Issue 12 (December 2024) , art. 127103, ISSN 1089-7666

DOI: 10.1063/5.0237554

12 p, 2.3 MB

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