Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 19 of 19 for “"Cassie-Baxter"”.
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Micro-textured surfaces for omniphobicity and drag-reduction
… The second part is an expansion of the classic Cassie-Baxter model that is widely used to predict the apparent contact angles on composite interfaces. A liquid droplet sitting on composite interfaces shows a range of apparent contact angles and corresponding contact angle hysteresis when the …
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A study of bubble wetting on surfaces
… leading to a prediction that a model based on a Cassie-Baxter analysis with knowledge of bubble wetting on a flat surface would be most accurate compared to other models. Dynamic and sessile bubble contact angles and droplet contact angles were measured on smooth acrylic, fluorosilanized silicon, …
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A study of static and dynamic robustness of hydro/omniphobic surfaces
Liquid droplets in the Cassie-Baxter state form liquid-air interfaces that are not flat but distorted due to pressure differences across the interfaces between the asperities. These distorted interfaces play an essential role in the transition from the composite Cassie-Baxter state to the …
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Droplet repellency of microfabricated surfaces in saturated environments
… scale pillar surfaces maintain the non-wetting Cassie-Baxter regime for drops of water over a range of saturation temperatures while micro scale waffles transition into a partially wetted state under the same conditions. Micro scale mushroom and waffle surfaces are able to maintain oleophobic …
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Contact Angle Of A Nano-Drop On A Heterogeneous Surface
… and contact angle on a homogeneous surface. Cassie and Baxter generalized this equation to heterogeneous surfaces implying that contact angle corresponds to the average properties of the surface under the drop. McCarthy and coworkers pointed out it is the nature of the substrate at droplet …
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Correlating feather structure, wettability, and robustness with ecological behavior of aquatic birds
… D*, and robustness factor, A*, according to the Cassie-Baxter relation for composite interfaces. This "effective microscopy" technique was successfully employed to assess the wettability and robustness of bird feather textures. The observable water-related behaviors of diving, wing-spreading, …
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Design and microfabrication of multifunctional bio-inspired surfaces
… an analytical model to study the stability of Cassie-Baxter state over Wenzel state for these hierarchical surfaces. In chapter 4 the fabrication and analysis of surfaces composed of controlled hierarchical levels, which combine sharkskin with single-level lotus leaf-inspired pillared …
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Hierarchical superhydrophobic aluminum surfaces for condensation applications
… were unable to achieve the proper Wenzel to Cassie-Baxter transition and produce a jumping behavior which is a necessary criterion for superhydrophobic condensation. However, the HCl etched aluminum surface was able to achieve heat transfer rates greater than the smooth, filmwise aluminum …
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Nuevos materiales de construcción ecosostenibles por su acción superhidrofugante
… a una rugosidad característica de un estado Cassie-Baxter) que dota a los materiales de propiedades auto-limpiantes. Sin embargo, los materiales superhidrofugantes presentan dos inconvenientes principales: (1) su baja durabilidad, y (2) su escasa resistencia a contaminantes de naturaleza …
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INFLUENCE OF STRUCTURAL AND CHEMICAL ASYMMETRY OF NANOSTRUCTURES ON THE KINETICS OF WETTING
… a form of wetting different from Wenzel and Cassie-Baxter states will arise. This form of wetting is commonly known as hemiwicking or 2D wicking, and involves a film of liquid wicking from the base of the droplet into the space between the nanostructures. The rate of imbibition of the wicking …
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Hairy interfaces
… on top of the hair after impact, similar to a Cassie-Baxter state. If the drop penetrates the hairy surface, the hairs can resist its spreading. Using this scenario as a reference case, we rationalize the role of the hairs in mitigating the inertia of the impacting drop through a balance of …
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Tailoring hydrodynamics of non-wetting droplets with nano-engineered surfaces
… is explored. The careful investigation of Cassie-Baxter to Wenzel transition of a pendant drop during the deposition explains that the rapid deceleration-induced water hammer pressure causes the transition. This new transition mechanism for large droplets enables a new wetting transition …
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Effects of micro- and nano-scale surface geometry on behaviors of live cells and liquid droplets
… surface. We observe that the well-known Cassie-Baxter and spherical cap models give poor estimates of characteristics such as contact angle and wet area and also fail to capture the complex liquid surface geometry when features have discrete size. Further exploring this theme, we consider …
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Microstructured materials synthesis via salt-assisted ultrasonic spray pyrolysis
… structured films are known to stabilize the Cassie-Baxter state and encourage superhydrophobic (or superhygrophobic) behavior. Very high surface area iron oxide microspheres can also easily be produced from USP. The crystallinity of the final product can be controlled by adjusting the …
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WETTING TRANSITIONS AT NANOSTRUCTURED SURFACES
… of a nanodroplet can be predicted by the local Cassie-Baxter mixing relation applied to the area within the interaction range from the drop’s perimeter, which, in turn, enables predictions of condensation and saturated vapor pressure above nanopatterned hydrophilic/hydrophobic surfaces. …
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Novels materials based on 2-dimensional arrays of metal nanoparticles and microparticles
… different levels of roughness required to form Cassie-Baxter superhydrophobic materials after modification with polyfluorothiols to lower the surface energy. In this thesis, the films were used as substrates for SERS detection following droplet evaporation from the surface but due to their …
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Physico-chemical hydrodynamics of droplets on textured surfaces with engineered micro/nanostructures
… pressure differences that cause failure of the Cassie- Baxter state that characterizes the super-repellent state for water and hexadecane droplets on the textured surfaces. In addition, dimensionless design parameters for quantifying the resistance to bending or buckling of the slender …
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Steady flow and stability analysis of a thin film over variable topography
The gravity-driven film flow over a flat inclined surface is a fundamental problem in fluid mechanics. This flow appears in many significant industrial, environmental and biomedical processes. Although this flow is a classic problem in fluid mechanics, nevertheless, in the real world, the …