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.
Results
Showing 1 to 20 of 28 for “"contact angle hysteresis"”.
-
Contact angle hysteresis and the energy principle
Experimental evidence suggests that contact angle hysteresis is related, in some cases, to surface roughness or heterogeneity on a microscopic scale. This work investigates the effect of periodic roughness or heterogeneity on quasi-static motion of a liquid/vapor/solid contact line. We determine …
-
Phase-Field Modeling of Oscillatory Wetting Phenomena with Contact Angle Hysteresis
… and Steen examines the connection between the contact line velocity and contact angle of liquid drops on an oscillating substrate that display contact angle hysteresis. Of particular interest in this experimental study is the analysis of the dependence of contact angle deviation on contact line …
-
Low-Gravity Sloshing in Spherical Tanks: Experimental Investigation Toward Numerical and Analytical Modeling
… pendulum model for simulating low-gravity free contact line fluid motion; and (iii) the development of numerical and analytical models for contact angle hysteresis. The experimental dataset, originating from the SILA (Sloshing Imaging and Load Analysis) payload, shows low- to large-amplitude …
-
Dropwise condensation on hydrophilic surfaces
… solid, hydrophilic surface (𝜃a = 38°) having low contact angle hysteresis (< 3°). We show that the distribution of droplet sizes for coalescing droplets agrees well with the classical distribution on hydrophobic surfaces. Our findings demonstrate that achieving stable dropwise condensation is not …
-
Bubble behavior in subcooled flow boiling on surfaces of variable wettability
… at departure to its upstream and downstream contact angles based on a rigid-body force balance between momentum and surface tension and assuming a skewed truncated spherical bubble shape. Both experimental and theoretical results predict that bubble width and height decrease with increasing …
-
Displacement of Fluid Droplets From Solid Surfaces
… Bond number B d and advancing and receding contact angles thetaA and thetaR. To determine the yield conditions, we conduct a computational study employing a spectral implementation of the boundary integral method for Stokes flow. In these computations, we develop a novel Newton iteration …
-
A study of bubble wetting on surfaces
… to other models. Dynamic and sessile bubble contact angles and droplet contact angles were measured on smooth acrylic, fluorosilanized silicon, glass, nylon, and silicon. These results were compared to the existing model, and the resulting error showed a strong correlation with a Pearson's …
-
Morphology-Property Relationships in Semicrystalline Aerogels of Poly(ether ether ketone)
… MW and increasing compressive modulus. Contact angle and contact angle hysteresis revealed that PEEK aerogels have a high contact angle, exceeding the conditions necessary to be classified as superhydrophobic materials. PEEK aerogel contact angle decreases with increasing density and a …
-
A liquid-in-glass thermometer with sub-microKelvin resolution, and its application for calorimetry
… level was read by a Michelson interferometer. Contact angle hysteresis was limited by a wetting film and the low meniscus velocity. The sub-microKelvin resolution achieved was the lowest known for any thermometer above cryogenic temperatures. The thermometer was modified for use as a batch …
-
Droplet behavior on superhydrophobic surfaces: Interfaces, interactions, and transport
… study of the transient response in terms of contact angle and contact radius of a sessile droplet on a smooth hydrophobic surface under electrical actuation is presented. A scaling analysis predicts the response time of a droplet during step actuation. It is shown that during time-varying …
-
Droplet manipulation on structured shape memory polymer surface
… two shapes under a water droplet overcomes contact angle hysteresis, resulting in driving a water droplet, when combined with the thermal Marangoni effect.
-
Influence of Surface Wettability on Drop Dynamics and Condensation
… specify the surface wettability: rest or static contact angle (_) and contact angle hysteresis (__). Partially non-wettable surfaces are characterized by static contact angles _ > 90° while partially wettable surfaces _ < 90°. Contact angle hysteresis, defined as the difference in dynamic …
-
The Design and Analysis of a Micro Squeeze Flow Rheometer
… carried out. The capillary effects, including contact angle hysteresis, and viscoelasticity associated with the liquid has been combined with the dynamics and electrical response of the rheometer itself to form a complete and consistent model. The validity of the model has been proven through …
-
Design and microfabrication of multifunctional bio-inspired surfaces
… this process manage to reach remarkably high contact angle and low contact angle hysteresis. Additionally, in this chapter we have introduced an analytical model to study the stability of Cassie-Baxter state over Wenzel state for these hierarchical surfaces. In chapter 4 the fabrication and …
-
Finite-element simulations of interfacial flows with moving contact lines
… framework for interfacial flows with moving contact lines. In our method, the contact line is advected naturally by the flow field. Contact angle hysteresis can be easily implemented without explicit calculation of the contact angle or the contact line velocity, and meshindependent results …
-
Parametric studies on dropwise condensation heat transfer
… behaviors and condensation heat transfer. Contact angle hysteresis (CAH) remains low at both high and low droplet contact angle, i.e. whether the surface is hydrophilic or hydrophobic. CAH increases with degree of wetting, but coating thermal conductance also increases. Details of drop …
-
Micro-textured surfaces for omniphobicity and drag-reduction
When a liquid droplet contacts a surface possessing the appropriate combination of surface texture and solid surface energy, the liquid may not penetrate into the surface texture. Instead, the droplet sits partially on air, forming a solid-liquid-air composite interface. Entrapped air pockets of …
-
Force and Energy Measurement of Bubble-Particle Detachment
… steps of the detachment process: Three-Phase-Contact pinning and three phase contact line sliding. The first step represents the energy barrier which must be overcome before detachment can begin. It is directly related to contact angle hysteresis. Detachment occurs during the second step, …
-
Cleaning and Dewatering Fine Coal using Hydrophobic Displacement
… be spontaneously displaced by any oil with a contact angle greater than ninety degrees in water. Based on these results, six methods of hydrophobic displacement were evaluated: hand shaking, screening, air classification, centrifugation, filtration, and displacement. In the first five methods …
-
Leveraging Capillarity
… energy cost with water, resulting in small contact areas with high advancing and receding contact angles and low contact angle hysteresis. This results in very low adhesion on the surfaces. Here we study the ability of superhydrophobic surfaces with their low adhesion to shed meltwater from …
Page 1 of 2