Droplet shape prediction on hierarchical and anisotropic microstructures

Jong, E. de (2013) Droplet shape prediction on hierarchical and anisotropic microstructures. Master's Thesis / Essay, Physics.

Preview	Text MasterThesisEdwinFinal.pdf - Published Version Download (2MB) | Preview
	Text DeJongAkkoordGiessen.pdf - Other Restricted to Registered users only Download (31kB)

Abstract

This master’s thesis covers two subjects in the theory on wetting. The basic theories are explained and through an introduction in contact angle calculations on microstructures, hierarchical structures are treated. An expression for the critical roughness for a droplet to be in the Cassie-Baxter state is found to be only dependent on one part of the microstructure unit cell. A generalization is made for additional hydrophobic states in hierarchical structures, resulting in state diagrams as a function of multi-level surface roughness. For two-level hierarchy, a critical four-state point is found for high nanolevel roughness and relatively low micro-level roughness. In the second part, a finite-element model is developed for microstructures that exhibit anisotropy. The droplet shape is then also anisotropic, and the droplets are being modeled based only on the assumption that every path from the center to the three-phase line is circular. For this, only the three-phase line has to be modeled. The model converges as expected, but the final droplet shapes are difficult to compare due to the lack of high-resolution material for comparison. The result heavily depends on the expression for the equilibrium contact angle, which is a function of the normal vector of the three-phase line. Quantities like length-over-width ratio and dependance of the droplet shape on the line tension are also computed and discussed.

Item Type:	Thesis (Master's Thesis / Essay)
Degree programme:	Physics
Thesis type:	Master's Thesis / Essay
Language:	English
Date Deposited:	15 Feb 2018 07:56
Last Modified:	15 Feb 2018 07:56
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/11593

Actions (login required)

View Item