Estudo da molhabilidade e superrepelência em duas dimensões usando modelo de Potts

• Ano de defesa: 2018
• Autor(a) principal: Lopes, Daisiane Molinos
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Santa Maria; Brasil; Física; UFSM; Programa de Pós-Graduação em Física; Centro de Ciências Naturais e Exatas
• Palavras-chave em Português: Transição; Cassie-Baxter; Wenzel; Superhidrofobicidade; Transition; Superhydrophobic; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: http://repositorio.ufsm.br/handle/1/15111

Our study to investigate the wettability of flat and structured surfaces in pillars based on two- dimensional simulations, using the Potts cellular model (CPM). We can find a superhydropic character on the surface when they presented: (I) High value of the contact angle (θ > 150°) formed between the liquid and the surface and (II)low hysteresis of the contact angle (Δθ< 10°). The drop on a surface may have two states of wettability: Cassie- Baxter, the liquid remains on the pillars surface, known as heterogeneous state or "fakir", and Wenzel, the liquid enters the cavities of the surface and is called state homogeneous. These studies show that between these two states there is an energy barrier that, when overcome, causes the transition of states. In our previous works, we also presented a model of at surface with a hydrophobic character, in order to obtain a surface with superhypophobic behavior (minimum contact between the drop and the surface). We studied which parameters can intensify this behavior and facilitate a possible transition. Thus, our structure of the surface with pillars and we vary the distance between them (b) and their height (h) to determine the transition zone of states. From the transition diagram, it was possible to analyze the behavior of parameters, such as contact angle, hysteresis and solid contact fraction in the regions near and far from the transition and also. We analyze how the parameters of the Potts model interfere in the wettability. In this study of the transition of states, we compared our model with the molecular dynamics model and therefore, having our results consistent with the experimental results found in the literature. Finally, we analyze how the reentrancy on the pillars influence the transition line.