scholarly journals Capillary Forces between Concave Gripper and Spherical Particle for Micro-Objects Gripping

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 285
Author(s):  
Zenghua Fan ◽  
Zixiao Liu ◽  
Congcong Huang ◽  
Wei Zhang ◽  
Zhe Lv ◽  
...  
Keyword(s):  
Spherical Particle ◽  
Liquid Bridge ◽  
Capillary Force ◽  
Numerical Procedure ◽  
Capillary Forces ◽  
Radius Ratio ◽  
Solid Surfaces ◽  
Capillary Bridge ◽  
Half Filling ◽  
Significant Attention

The capillary action between two solid surfaces has drawn significant attention in micro-objects manipulation. The axisymmetric capillary bridges and capillary forces between a spherical concave gripper and a spherical particle are investigated in the present study. A numerical procedure based on a shooting method, which consists of double iterative loops, was employed to obtain the capillary bridge profile and bring the capillary force subject to a constant volume condition. Capillary bridge rupture was characterized using the parameters of the neck radius, pressure difference, half-filling angle, and capillary force. The effects of various parameters, such as the contact angle of the spherical concave gripper, the radius ratio, and the liquid bridge volume on the dimensionless capillary force, are discussed. The results show that the radius ratio has a significant influence on the dimensionless capillary force for the dimensionless liquid bridge volumes of 0.01, 0.05, and 0.1 when the radius ratio value is smaller than 10. The effectiveness of the theorical approach was verified using simulation model and experiments.

Squeeze Effects in a Flat Liquid Bridge Between Parallel Solid Surfaces

2006 ◽  
Vol 128 (3) ◽  
pp. 575-584 ◽  
Author(s):  
Marie-Hélène Meurisse ◽  
Michel Querry
Keyword(s):  
Analytical Model ◽  
Liquid Bridge ◽  
External Load ◽  
Normal Force ◽  
Capillary Forces ◽  
Solid Surfaces ◽  
Capillary Suction ◽  
Capillary Effects ◽  
Liquid Lubricant ◽  
Normal Forces

When a liquid lubricant film fractionates into disjointed liquid bridges, or a unique liquid bridge forms between solid surfaces, capillary forces strongly influence the action of the fluid on the solid surfaces. This paper presents a theoretical analytical model to calculate the normal forces on the solid surfaces when squeezing a flat liquid bridge. The model takes into account hydrodynamic and capillary effects and the evolution of the geometry of the liquid bridge with time. It is shown that the global normal force reverses during the squeezing motion except in the case of perfect nonwetting; it is attractive at the beginning of the squeezing motion, and becomes repulsive at small gaps. When the external load is constant, capillary suction tends to accelerate the decrease in gap dramatically.

Effect of Contact Angle Hysteresis on Liquid Bridge while Sphere Particles are in Relative Movement

2013 ◽  
Vol 634-638 ◽  
pp. 2945-2948
Author(s):  
Song Yang ◽  
Jun Hua Wu ◽  
Xin Wang
Keyword(s):  
Contact Angle ◽  
Liquid Bridge ◽  
Capillary Force ◽  
Contact Angle Hysteresis ◽  
Capillary Forces ◽  
Hysteresis Effect ◽  
Liquid Volume ◽  
Liquid Bridges ◽  
Relative Movement ◽  
Important Impact

Hysteresis effect of contact angle has an important impact on liquid bridges between sphere particles. This effect is not limited to increasing liquid volume of fixed particles. The hysteresis effect of contact angle is expressed by fixed liquid volume while the two sphere particles are in relative movement. The hysteresis effect of contact angle on the liquid bridge is also significant. In this paper, the hysteresis effect of contact angle on capillary forces of liquid bridges is analyzed when the two sphere particles are in relative movement. Results indicate that contact angle hysteresis effects on capillary force are significant.

Exact Solution for Capillary Bridges Properties by Shooting Method

2017 ◽  
Vol 72 (4) ◽  
pp. 315-320 ◽  
Author(s):  
Li Qiang-Nian ◽  
Zhang Jia-Qi ◽  
Zhou Feng-Xi
Keyword(s):  
Exact Solution ◽  
Liquid Bridge ◽  
Capillary Force ◽  
Shooting Method ◽  
Moving Boundary ◽  
Contact Angles ◽  
Spherical Particles ◽  
Capillary Bridge ◽  
Capillary Suction ◽  
Wet Particles

AbstractThe investigation of liquid bridge force acting between wet particles has great significance in many fields. In this article, the exact solution of capillary force between two unequal-sized spherical particles is investigated. Firstly, The Young-Laplace equation with moving boundary is converted into a set of ordinary differential equations with two fix point boundary using variable substitution technique, in which the gravity effects have been neglected. The geometry of the liquid bridge between two particles is solved by shooting method. After that, the gorge method is applied to calculate the capillary-bridge force that is consists of contributions from the capillary suction and surface tension. Finally, the effect of various parameters including distance between two spheres, radii of spheres, and contact angles on the capillary force are investigated. It is shown that the presented approach is an efficient and accurate algorithm for capillary force between two particles in complex situations.

A Scheme of Micromanipulation using a Liquid Bridge

2003 ◽  
Vol 782 ◽  
Author(s):  
Kenichi J. Obata ◽  
Shigeki Saito ◽  
Kunio Takahashi
Keyword(s):  
Stability Analysis ◽  
Liquid Bridge ◽  
Capillary Force ◽  
Capillary Forces ◽  
Target Object ◽  
Liquid Volume ◽  
Target Point ◽  
The Stability

ABSTRACTThis paper presents a scheme of micromanipulation with a liquid bridge and an analysis of the capillary forces involved. The following procedure is considered in this article: (a) PICK UP: a probe, with liquid in the tip, approaches the target object. (b) A liquid bridge forms between the object and the tip of the probe. (c) The object is picked up by means of the capillary force of the liquid bridge. (d) TRANSPORT: The probe ascends, moves to the target point, and descends towards a substrate. (e) PLACEMENT: At a given height, a second liquid bridge made from a drop previously applied at the target point on the substrate, forms between the object and the substrate. (f) The probe ascends and the probe-object bridge collapses.The collapse can be predicted through the stability analysis of the bridge and its condition can be controlled by the regulation of the liquid volume. The liquid volumes required for the manipulation, in the first and second liquid bridge, are calculated in this paper.

The profile of a capillary liquid bridge between solid surfaces

2010 ◽  
Vol 78 (3) ◽  
pp. 277-286 ◽  
Author(s):  
J. W. van Honschoten ◽  
N. R. Tas ◽  
M. Elwenspoek
Keyword(s):  
Liquid Bridge ◽  
Solid Surfaces ◽  
Capillary Liquid

The Capillary Force Between an AFM Tip and a Surface at Different Humidity

2008 ◽  
Author(s):  
Sheng Chau Chen ◽  
Jen Fin Lin
Keyword(s):  
Relative Humidity ◽  
Capillary Force ◽  
Present Model ◽  
Hydrophobic Surface ◽  
Contact Angles ◽  
Solid Surfaces ◽  
Hydrophilic Surface ◽  
Solid Bodies ◽  
Force Equilibrium ◽  
Good Agreement

In the present study, the meniscus profiles of water bridges formed at different relative humidity are determined using the geometric relationships including the Kelvin equation and the force equilibrium formula established for the meniscus. The pull-off forces predicted by the present model show good agreement with the experimental results reported in the literatures. When the contact angles at two solid bodies are equal, the pull-off force is slightly elevated by an increase of the relative humidity of air, and is significantly elevated by an increase of the asperity radius. Furthermore, two hydrophobic surfaces with equally large contact angles lower the pull-off force. If a difference exists between the contact angles of two solid surfaces, the asperity with a hydrophilic surface incorporating with a smooth flat plate with a hydrophobic surface reduces the pull-off force.

Capillary Forces between Two Spheres with a Fixed Volume Liquid Bridge:  Theory and Experiment

Langmuir ◽  
2005 ◽  
Vol 21 (24) ◽  
pp. 10992-10997 ◽  
Author(s):  
Yakov I. Rabinovich ◽  
Madhavan S. Esayanur ◽  
Brij M. Moudgil
Keyword(s):  
Liquid Bridge ◽  
Capillary Forces ◽  
Fixed Volume ◽  
Theory And Experiment

The Mechanism and Feasibility of Self-Assembly with Capillary Force

2007 ◽  
Vol 339 ◽  
pp. 234-239 ◽  
Author(s):  
D.P. Zhao ◽  
D. Wu ◽  
K. Chen
Keyword(s):  
Self Assembly ◽  
Binding Sites ◽  
Capillary Force ◽  
Capillary Forces ◽  
Interfacial Free Energy ◽  
The Self ◽  
Material System ◽  
Self Assembling ◽  
Hydrophilic Material ◽  
Micro Parts

This paper introduces a fluidic technique based on patterned shapes of hydrophobic self-assembly monolayers (SAMs) and capillary forces to self-assemble micro-parts onto substrates. Self-assembly is defined as a spontaneous process that occurs in a statistical, non-guided fashion. More specifically, the fluidic self-assembly with capillary force is driven by the gradient in interfacial free energy when a micro-part approaches a substrate binding site. In this paper, the mechanism of self-assembly with capillary forces is proposed. The hydrophobic-hydrophilic material system between the binding sites and micro-parts is then simulated. Finally, the surface energy of a self-assembling system in the liquid phase under different conditions is calculated. The results show that shift, twist, lift and tilts displacements are detected to be rather uncritical and the system turns out to be rather stiff with respect to such displacements. The theoretical result is supported by the experiments and gives quantitive explanations why and how the capillary force works in the self-assembly process.

An analytical theory for the capillary bridge force between spheres

2016 ◽  
Vol 812 ◽  
pp. 129-151 ◽  
Author(s):  
N. P. Kruyt ◽  
O. Millet
Keyword(s):  
Laplace Equation ◽  
Capillary Force ◽  
Numerical Solutions ◽  
Analytical Theory ◽  
Phase Contact ◽  
Capillary Bridge ◽  
Contact Circle ◽  
Three Phase ◽  
Meridional Profile ◽  
Rupture Criterion

An analytical theory has been developed for properties of a steady, axisymmetric liquid–gas capillary bridge that is present between two identical, perfectly wettable, rigid spheres. In this theory the meridional profile of the capillary bridge surface is represented by a part of an ellipse. Parameters in this geometrical description are determined from the boundary conditions at the three-phase contact circle at the sphere and at the neck (i.e. in the middle between the two spheres) and by the condition that the mean curvature be equal at the three-phase contact circle and at the neck. Thus, the current theory takes into account properties of the governing Young–Laplace equation, contrary to the often-used toroidal approximation. Expressions have been developed analytically that give the geometrical parameters of the elliptical meridional profile as a function of the capillary bridge volume and the separation between the spheres. A rupture criterion has been obtained analytically that provides the maximum separation between the spheres as a function of the capillary bridge volume. This rupture criterion agrees well with a rupture criterion from the literature that is based on many numerical solutions of the Young–Laplace equation. An expression has been formulated analytically for the capillary force as a function of the capillary bridge volume and the separation between the spheres. The theoretical predictions for the capillary force agree well with the capillary forces obtained from the numerical solutions of the Young–Laplace equation and with those according to a comprehensive fit from the literature (that is based on many numerical solutions of the Young–Laplace equation), especially for smaller capillary bridge volumes.

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