4 edition of A study of advancing & receding contact angles and contact angle hysteresis found in the catalog.
A study of advancing & receding contact angles and contact angle hysteresis
C. N. Catherine Lam
Thesis (M.A.Sc.) -- University of Toronto, 2001.
|Series||Canadian theses = -- Thèses canadiennes|
|The Physical Object|
|Pagination||2 microfiches : negative. --|
Since contact angles are measured from captured images, they can be used for analysis of advancing, receding and most stable contact angles and contact angle hysteresis. Although measurement of adhesion forces is in its early stage, it has revealed several interesting findings, including the pinned to a solid surface with different advancing and receding con-tact angles due to the heterogeneity of microscopic adhesion forces, the morphology, and the material's elasticity. The pair of advancing and receding contact angles can be replaced by a sliding angle (the inclination angle of the plate) for characterization,44,45,58 which is
The effect of drop (bubble) size on advancing and receding contact angles for heterogeneous and rough solid surfaces as observed with sessile-drop and captive-bubble With the Attension Sigma force tensiometer, the Wilhelmy method can be used to define dynamic contact solid surface is attached to a balance hook and is immersed in a test liquid to calculate the advancing contact angle. The solid is then lifted from the test liquid and the receding angle can be ://
Nevertheless, to obtain these surface energies you must do the experiments and measure contact angle on the dry substrate and wetted one or take needed data from others’ experiments, e.g. from An Experimental Study of Contact Angle Hysteresis Extrand CW(1), Kumagai Y. Author information: (1)Fluoroware, Jonathan Boulevard North, Chaska, Minnesota, Advancing and receding contact angles of four organic liquids and water were measured on a variety of polymer surfaces and silicon wafers using an inclinable ://
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The difference between the advancing and receding contact angles is known as the contact angle hysteresis, θ hyst: (2) θ hyst =θ a −θ r Practically, all solid surfaces exhibit contact angle hysteresis and because of this hysteresis, the contact angle interpretation in terms of Young's :// Contact angle hysteresis is a difference between advancing and receding angles.
Contact angle hysteresis arises from the chemical and topographical heterogeneity of the surface, or swelling, rearrangement or alteration of the surface by the solvent. Contact angle hysteresis cannot be measured directly but through the measurement of advancing The hysteresis angles (Fig.
6a) of the films were calculated based on the contact angle test, using the difference between the advancing (maximum) and receding (minimal) contact :// The line energy associated with the triple phase contact line is a function of local surface defects (chemical and topographical); however, it can still be calculated from the advancing and receding contact angles to which those defects give rise.
In this study an expression for the line energy associated with the triple phase contact line is :// (v) Contact angle hysteresis: advancing Vs receding contact angle.
Contact angle measured for a liquid advancing across a surface exceeds that of one receding from the surface. Contact angle is generally attributed to surface roughness, surface heterogeneity, solution impurities adsorbing on the surface, or Unlike the previous one-cycle measurements that have been made in a number of studies, these cycling contact angle measurements provide more information on the mechanisms of contact angle hysteresis θ hyst.
Both the advancing contact angles θ a (except for the one measured from the first cycle) and the receding contact angles θ r obtained The hysteresis generally decreases with decreasing of the contact angles. The lowest water contact angle hysteresis H w was obtained for reference variant O—without sandblasting—where only degreasing treatment was used (H w = degrees).
After sandblasting the lowest water contact angle hysteresis H w was obtained in sandblasting variant D-G (H w = degrees) and in variants of The difference between the advancing and receding contact angles, i.e., the contact angle hysteresis, is of paramount importance in wetting and capillarity.
For example, it determines the magnitude of the external force that is required to make a drop slide on a solid :// hysteresis as the difference of the advancing contact angle and the receding contact angle for a contact line moving in an opposite direction at the same velocity.
As sketched in Fig. 2, one can see that this difference in fact consists of two parts. First, there is a jump in the contact angle at zero velocity. This jump, known as the contact Contact angle, θ (theta), is a quantitative measure of wetting of a solid by a liquid.
The contact angle is geometrically defined as the angle formed by a liquid at the three-phase boundary where a liquid, gas, and solid intersect.
There are three different forces acting on this three-phase contact point between solid, fluid and fluid. Contact angles can be divided into static, dynamic and Contact angle hysteresis is an important physical phenomenon.
It is omnipresent in nature and also plays a crucial role in various industrial processes. Despite its relevance, there is a lack of consensus on how to incorporate a description of contact angle hysteresis into physical models. To clarify this, starting from the basic definition of contact angle hysteresis, we introduce the Droplets sliding on surfaces always exhibit an advancing and a receding contact angle.
When exerting different driving forces on the droplet to force it to slide at different velocities, the droplet would alter its shape to adapt to the new motion. Hence, different advancing/receding contact angles are likely to be observed, leading to the multiple contact angle hysteresis on a given surface These surfaces have very large static advancing contact angles and little static contact angle hysteresis.
In this study, the dynamic advancing and dynamic receding contact angles on superhydrophobic surfaces were measured as a function of plate velocity and capillary :// Request PDF | Dynamic Cycling Contact Angle Measurements: Study of Advancing and Receding Contact Angles | Dynamic cycling contact angle (DCCA) measurements of surfaces have very large static advancing contact angles and little static contact angle hysteresis.
In this study, the dynamic advancing and dynamic receding contact angles on superhydrophobic surfaces were measured as a function of plate velocity and capillary number. The dynamic contact angles measured on a smooth In this work, the effects of surface texturing (pillar size, spacing, and height) on wettability, contact angle hysteresis, and “robustness” are investigated.
We study the static, advancing, and receding contact angles, as well as the sliding angles as a function of the solid area :// The difference between the advancing and receding angles is known as the dynamic contact angle hysteresis, '.
The size of the [ A, ] domain is usually attributed to the surface roughness of the solid substrate, and the Young angle lies somewhere within this domain (Van Mourik, ).
Contact angle hysteresis is useful for characterizing We study the interface dynamics and contact angle hysteresis in a two dimensional, chemically patterned channel described by the Cahn-Hilliard equation with a relaxation boundary :// /_A_new_model_for_contact_angle_hysteresis. Three types of experiments were used to study advancing and receding contact angles (and contact angle hysteresis), narnely the dynamic one-cycle contact angle (DOCA), the dynamic cycling contact angle (DCCA) and the dynamic one-cycle-soaking contact angle (DOSCA) :// In other words, contact angle hysteresis is observed because a threshold force is required to start a droplet sliding.
Once sliding, the droplet exhibits dynamic advancing and receding contact angles θ a and θ r, and force must be continually applied to maintain the sliding against the dynamic hysteresis.
To clarify further, contact angle. The advancing contact angle and the receding contact angles are all less than 90 0 (hydrophilicity), with the advancing contact angles on silver and silver oxide thin films similar to the static Contact Angles and Their Hysteresis as a Measure of Liquid−Solid Adhesion.
Langmuir20 (10), DOI: /la Dmitri Chvedov and, Alison Arnold. Effect of Surface Topography of a Rolled Sheet on Contact :// mental method, we have measured the dynamic advancing and receding contact angles and the resulting hysteresis of droplets under electrowetting-on-dielectric (EWOD).
Measurements were obtained over wide ranges of applied EWOD voltages, orelectrowettingnumbers(0eEw e), anddroplet sliding speeds,orcapillarynumbers( 10 5 eCae 10 3) Langmuir Nelson Dynamic CA hyst