Droplets on Micro Structured or Patterned Surfaces With Different Roughness Parameters

2010 ◽  
Author(s):  
Y. Y. Yan ◽  
Y. Q. Zu ◽  
C. Q. Tian ◽  
N. Gao
Keyword(s):  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Wetting Transition ◽  
Patterned Surfaces ◽  
Roughness Parameters ◽  
Surface Wetting ◽  
Wetting Properties ◽  
Proposed Model ◽  
Simulation Based ◽  
Boltzmann Method

Surface wetting properties play important roles in boiling and condensation. In this paper, the wetting behaviours of a single droplet on micro structured or patterned surfaces with different roughness parameters are investigated theoretically and numerically. A theoretical model is proposed to study wetting transitions. Comparison between results obtained by theoretical analysis with those of experiment indicates that the proposed model can give a better prediction of wetting transition. In addition, a numerical simulation based on lattice Boltzmann method (LBM) is performed to study surface wetting properties and also the evolution of droplet shapes, dynamic contact angle and corresponding velocity fields. In the simulation, the droplet size is comparable with the scale of micro posts on the surface.

scholarly journals Capillary transfer of soft films

2020 ◽  
Vol 117 (10) ◽  
pp. 5210-5216 ◽  
Author(s):  
Yue Zhang ◽  
Mengtian Yin ◽  
Yongmin Baek ◽  
Kyusang Lee ◽  
Giovanni Zangari ◽  
...  
Keyword(s):  
High Speed ◽  
Computational Analysis ◽  
Liquid Surface ◽  
Theoretical Models ◽  
Dynamic Contact ◽  
Surface Wetting ◽  
Motion Direction ◽  
Wetting Properties ◽  
Geometric Patterns ◽  
Solid Substrates

Existing transfer technologies in the construction of film-based electronics and devices are deeply established in the framework of native solid substrates. Here, we report a capillary approach that enables a fast, robust, and reliable transfer of soft films from liquid in a defect-free manner. This capillary transfer is underpinned by the transfer front of dynamic contact among receiver substrate, liquid, and film, and can be well controlled by a selectable motion direction of receiver substrates at a high speed. We demonstrate in extensive experiments, together with theoretical models and computational analysis, the robust capabilities of the capillary transfer using a versatile set of soft films with a broad material diversity of both film and liquid, surface-wetting properties, and complex geometric patterns of soft films onto various solid substrates in a deterministic manner.

scholarly journals Wetting and spreading of droplets on rough aluminum surfaces

2019 ◽  
Vol 196 ◽  
pp. 00024
Author(s):  
Anastasia Islamova ◽  
Konstantin Ponomarev
Keyword(s):  
Contact Angle ◽  
Aluminum Alloy ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Arithmetic Mean ◽  
Distilled Water ◽  
Roughness Parameters ◽  
Shadow Method ◽  
Profile Deviation ◽  
Aluminum Surfaces

The wetting and spreading of distilled water droplets on abrasion-treated aluminum alloy AlMg 6 surfaces were studied. Using the shadow method, the dependences of the dynamic contact angle and hysteresis on the arithmetic mean of the profile deviation were obtained. Based on the analysis of the height and hybrid 3D roughness parameters, a relationship between the texture and spreading of the droplet is established.

Surface Composition and Morphology of CTMP Fibers

Holzforschung ◽  
1999 ◽  
Vol 53 (2) ◽  
pp. 188-194 ◽  
Author(s):  
Linda Börås ◽  
Paul Gatenholm
Keyword(s):  
Contact Angle ◽  
Surface Composition ◽  
Bulk Composition ◽  
Dynamic Contact Angle ◽  
Fiber Surface ◽  
Dynamic Contact ◽  
Phase Imaging ◽  
Peroxide Bleaching ◽  
Wetting Properties ◽  
Experimental Findings

Summary The aim of this study was to investigate the surface composition and morphology of Chemithermomechanical pulp (CTMP) fibers from spruce. The fibers were exposed to a sequence of mild treatments such as washing, peroxide bleaching and extraction. The effects of treatments on fiber bulk composition and surface properties were investigated. All treatments did not significantly result in changes in total lignin and carbohydrate content. However, the extractives were stepwise removed. With the Electron Spectroscopy for Chemical Analysis (ESCA) technique, a gradual reduction of unoxidized carbon in the C1s resolved peak was shown, which was correlated to the removal of non-carbohydrates. Variations in surface topography among the analyzed samples were displayed with Atomic Force Microscopy (AFM) imaging of fibers in tapping mode. The wetting properties of all pulps were measured by Dynamic Contact Angle (DCA) on the single fibers. The advancing contact angle decreased and the hysteresis is also reduced, as a result of treatments. ESCA, AFM and contact angle analyses suggest that the extractives are distributed as globular particles at the fiber surface. Phase imaging AFM indicated the presence of lignin as irregular patches at the surface. A model of the CTMP fiber surface based on experimental findings in this work is proposed.

Investigation of behavior of the dynamic contact angle in a problem of convective flows

2017 ◽  
Vol 5 (4) ◽  
pp. 27-42
Author(s):  
O.N Goncharova ◽  
◽  
I.V. Marchuk ◽  
A.V. Zakurdaeva ◽  
◽  
...  
Keyword(s):  
Contact Angle ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Convective Flows

Effect on Sedimentation Characteristics of Bentonite Suspension at Different Conditions

2013 ◽  
Vol 333-335 ◽  
pp. 2004-2009
Author(s):  
Lin Ling Jiang ◽  
Wei Mo ◽  
Xiao Jing Yang ◽  
Tian Li Xue ◽  
Shao Jian Ma
Keyword(s):  
Contact Angle ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Sodium Pyrophosphate ◽  
Sedimentation Rates ◽  
Sedimentation Analysis ◽  
Ph Values ◽  
Bentonite Suspension ◽  
Sedimentation Time ◽  
Sedimentation Processes

To better understand the sedimentation processes of bentonite, the sedimentation characteristic of bentonite suspension was studied by using the sedimentation analysis module of Dynamic Contact Angle Meter and Tensiometer. The results indicated that sedimentation characteristics of bentonite suspension were affected by the concentration and pH values of the suspension together with the dosage of dispersants. The natural sedimentation rates of bentonite suspension declined firstly with prolonging the sedimentation time and soon stabilized after about 50s. The sedimentation weight of particles hardly changed when the concentration ranged from 0.5% to 5.0%, while it increased significantly when ranged from 5.0% to 10.0%. The sedimentation weight and rate were relatively bigger at 4.4, 11.8 than that of 6.0, 7.9, and the maximum values appeared at pH11.8. Adding sodium pyrophosphate could improve the dispersibility of bentonite suspension.

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