Equilibrium Contact Angles of Liquid Droplets on Ideal Rough Solids

Langmuir ◽  
2011 ◽  
Vol 27 (24) ◽  
pp. 14910-14918 ◽  
Author(s):  
Hie Chan Kang ◽  
Anthony M. Jacobi
Keyword(s):  
Contact Angles ◽  
Liquid Droplets

Emission of Liquid Droplets From the Interface of Bidrops Pulled by a Ferrofluid in a Microchannel

2009 ◽  
Author(s):  
Yuichi Shibata ◽  
Kota Takamine ◽  
Masahiro Kawaji
Keyword(s):  
Liquid Droplet ◽  
Contact Angles ◽  
Liquid Interface ◽  
Liquid Droplets ◽  
Liquid Slug ◽  
Immiscible Liquids ◽  
Static Contact ◽  
Circular Microchannel ◽  
And Behavior ◽  
The Relationship

The field of microfluidics is developing with advances in biotechnology and μ-TAS technologies. In various devices, controlling the flow rate of liquid or gas accurately at micro or nanoliter volume levels is required. By using a ferrofluid, the flow of a liquid or gas in a microchannel can be controlled by the driving power exerted on the ferrofluid. In a previous study, an unsteady flow of a liquid slug caused by the driving force exerted by the ferrofluid was investigated in a 200μm circular microchannel. The velocity of the ferrofluid was found to be affected by the physical properties of the liquids being pulled, such as the dynamic and static contact angles, surface tension and kinematic viscosity of the liquid slugs. At sufficiently high velocities of the ferrofluid, emission of a liquid droplet from the liquid-liquid interface was observed. In the present study, combinations of various liquids with the ferrofluid were examined in two microchannels (130μm and 200μm diameter). The relationship between the emission of liquid droplets and interfacial fluctuation of the bidrops was investigated experimentally and analytically. The emission of liquid droplets from the interface and behavior of the interface were observed using liquids of different viscosities. The interfacial shape changed continuously until a liquid droplet was emitted from the interface of the immiscible liquids. When the ferrofluid velocity was increased, necking of the liquid-liquid interface occurred continuously and some liquid droplets were emitted from the interface. We could study the characteristics of emission of liquid droplets from the interfacial variation.

The Properties of Liquid Phase Embryos at the Intersections of Plane Solid Surfaces

1952 ◽  
Vol 5 (4) ◽  
pp. 618
Author(s):  
RG Wylie
Keyword(s):  
Contact Angle ◽  
Solid Surface ◽  
Contact Angles ◽  
Solid Surfaces ◽  
Boundary Line ◽  
Pure Liquid ◽  
Liquid Droplets ◽  
Free Energies ◽  
Different Types ◽  
Kinetics Of

In order to calculate the probabilities of nucleation of liquid droplets at different types of site on a solid surface, the properties of embryonic droplets which may exist in complete thermodynamic equilibrium at those sites must be known. The general properties of liquid embryos formed on a plane solid surface, or at lines or points of intersection of plane solid surfaces, are considered. It is shown that, although an edge free energy associated with the boundary line may substantially affect the properties -of embryos at small contact angles, the effect is probably not large, for embryos of the sizes of interest, when the contact angle is larger than about π/4. The areas, volumes, total surface free energies, and free energies of formation are found for embryos at these sites as functions of the contact angle, any edge free energies being neglected. The extension to the formation of bubbles at plane solid surfaces in a pure liquid is indicated. The results are applied in a following paper to the kinetics of condensation of a vapour at an imperfect crystalline surface.

Automated Drop-on-Fiber contact angle measurement using a microrobotic platform

2014 ◽  
Vol 29 (2) ◽  
pp. 225-231 ◽  
Author(s):  
Pooya Saketi ◽  
Juha Hirvonen ◽  
Yuli Lai ◽  
Christian Ganser ◽  
Christian Teichert ◽  
...  
Keyword(s):  
Contact Angle ◽  
Natural Fibers ◽  
Contact Angle Measurement ◽  
Contact Angles ◽  
Angle Measurement ◽  
Structural Factors ◽  
Fibrous Materials ◽  
Liquid Droplets ◽  
Fiber Volume ◽  
Pulp Paper

Abstract Measuring contact angles on single fibers enables the separation of structural factors from surface chemistry factors. Current Drop-on-Fiber (DOF) contact angle measurement methods for natural fibers generally, and for pulp/paper fibers specifically, present a number of challenges. These are manipulation and mounting of the microscale fibers, straightening natural fibers to produce repeatable axisymmetric droplet conformation, measuring the droplet volume excluding the fiber volume and also human errors due to manually performed tasks. This paper presents a novel method to measure contact angles in DOF systems and overcome the above mentioned challenges using microrobots. The proposed microrobotic platform is capable of handling natural and synthetic fibrous materials in microscale, and dispensing probe liquid droplets down to 12 nl. It measures contact angle values using computer vision and a droplet-profiledetection algorithm. It reports the contact angle values as a function of volume of the droplet. The paper validates the capabilities of the proposed platform by applying three commonly used probe liquids: deionized water, ethylene glycol and diiodomethane for measuring contact angles on glass and pulp fibers. Finally, the results are compared with a picoliter contact angle measurement approach.

Droplets Atop a Wrinkled Substrate

2010 ◽  
Vol 224 (11) ◽  
pp. 2459-2467 ◽  
Author(s):  
Y Zhang ◽  
H Fan ◽  
W Huang ◽  
Y Chen
Keyword(s):  
Surface Roughness ◽  
Thin Layer ◽  
Shape Memory Polymer ◽  
Contact Angles ◽  
Liquid Droplets ◽  
Patterned Substrates ◽  
Apparent Effect ◽  
Patterned Substrate ◽  
Static Contact ◽  
Substrate Surfaces

Liquid droplets atop both isotropically and anisotropically patterned substrate surfaces are investigated experimentally. The patterns are realized by means of elastic wrinkling/buckling of a thin layer of gold coated atop polystyrene shape memory polymer. Static contact angles are measured, and images showing the shapes of droplets are captured. The results obtained from isotropically patterned substrates suggest that surface roughness has no apparent effect on the static contact angles in this study. However, atop anisotropically patterned substrates, both the static contact angles and shapes of droplets vary with the direction of wrinkles and size of droplets.

scholarly journals Motion of liquid Droplets in gas channels in a SO2 Module

2021 ◽  
Author(s):  
Radu Cimpeanu ◽  
Yousef Daneshbod ◽  
Qingxia Li ◽  
Pejman Sanaei ◽  
Pavel Dubovski ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Porous Material ◽  
Thin Liquid Film ◽  
Travelling Wave ◽  
Contact Angles ◽  
Operating Conditions ◽  
Liquid Droplets ◽  
Single Droplet ◽  
Wave Type ◽  
Droplet Dynamics

Understanding of liquid droplets dynamics in gas channels is critical for improvement of performance and durability of the catalysts made of a dense porous material. This report describes a mathematical model for studying how different surface properties and operating conditions affect the dynamics of liquid droplets. We present multiple numerical simulations of a single droplet dynamics for different sizes of droplets and different choices of contact angles. We also study influence of an air flow to a thin liquid film and obtained travelling wave type solutions.

Spreading of Liquid Droplets on Cylindrical Surfaces: Accurate Determination of Contact Angle.

1989 ◽  
Vol 170 ◽  
Author(s):  
H. Daniel Wagner ◽  
E. Wiesel ◽  
H. E. Gallis
Keyword(s):  
Contact Angle ◽  
Liquid Droplet ◽  
Glass Fibers ◽  
Accurate Determination ◽  
High Strength ◽  
Contact Angles ◽  
Liquid Droplets ◽  
Liquid Polymers ◽  
Solid Liquid Interface ◽  
Solid Liquid

AbstractThe wetting of cylindrical monofilaments by liquid polymers is a problem of much scientific and technological importance. In particular, the characterization of the physicochemical nature of interfaces is a key problem in the field of advanced fibrous composites. The macroscopic regime contact angle, which reflects the energetics of wetting at the solid-liquid interface, is difficult to measure by usual methods in the case of very thin cylindrical fibers.In the present article a numerical method is proposed for the calculation of macroscopic regime contact angles from the shape of a liquid droplet spread onto a cylindrical monofilament. This method, which builds on earlier theoretical treatments by Yamaki and Katayama [1], and Carroll [2], very much improve the accuracy of the contact angle obtained. Experimental results with high-strength carbon, para-aramid, and glass fibers, are presented to demonstrate the high degree of accuracy of the method proposed.

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