Hydrosilation-Cured Poly(dimethylsiloxane) Networks:  Intrinsic Contact Angles via Dynamic Contact Angle Analysis

2003 ◽  
Vol 36 (10) ◽  
pp. 3689-3694 ◽  
Author(s):  
Janelle M. Uilk ◽  
Ann E. Mera ◽  
Robert B. Fox ◽  
Kenneth J. Wynne
Keyword(s):  
Contact Angle ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Contact Angle Analysis

scholarly journals Numerical Bifurcation Analysis of a Film Flowing over a Patterned Surface through Enhanced Lubrication Theory

Fluids ◽  
2021 ◽  
Vol 6 (11) ◽  
pp. 405
Author(s):  
Nicola Suzzi ◽  
Giulio Croce
Keyword(s):  
Contact Angle ◽  
Bifurcation Analysis ◽  
Dynamic Contact Angle ◽  
Flow Characteristics ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Inclined Plate ◽  
Lubrication Equation ◽  
Static Contact ◽  
Numerical Bifurcation

The bifurcation analysis of a film falling down an hybrid surface is conducted via the numerical solution of the governing lubrication equation. Instability phenomena, that lead to film breakage and growth of fingers, are induced by multiple contamination spots. Contact angles up to 75∘ are investigated due to the full implementation of the free surface curvature, which replaces the small slope approximation, accurate for film slope lower than 30∘. The dynamic contact angle is first verified with the Hoffman–Voinov–Tanner law in case of a stable film down an inclined plate with uniform surface wettability. Then, contamination spots, characterized by an increased value of the static contact angle, are considered in order to induce film instability and several parametric computations are run, with different film patterns observed. The effects of the flow characteristics and of the hybrid pattern geometry are investigated and the corresponding bifurcation diagram with the number of observed rivulets is built. The long term evolution of induced film instabilities shows a complex behavior: different flow regimes can be observed at the same flow characteristics under slightly different hybrid configurations. This suggest the possibility of controlling the rivulet/film transition via a proper design of the surfaces, thus opening the way for relevant practical application.

Spreading-Droplet Simulation With Surface Tension Model Using Inter-Particle Force in Particle Method

2013 ◽  
Author(s):  
Eiji Ishii ◽  
Taisuke Sugii
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Dynamic Contact Angle ◽  
Particle Method ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Particle Methods ◽  
Static Contact ◽  
Particle Force ◽  
Surface Tension Model

Predicting the spreading behavior of droplets on a wall is important for designing micro/nano devices used for reagent dispensation in micro-electro-mechanical systems, printing processes of ink-jet printers, and condensation of droplets on a wall during spray forming in atomizers. Particle methods are useful for simulating the behavior of many droplets generated by micro/nano devices in practical computational time; the motion of each droplet is simulated using a group of particles, and no particles are assigned in the gas region if interactions between the droplets and gas are weak. Furthermore, liquid-gas interfaces obtained from the particle method remain sharp by using the Lagrangian description. However, conventional surface tension models used in the particle methods are used for predicting the static contact angle at a three-phase interface, not for predicting the dynamic contact angle. The dynamic contact angle defines the shape of a spreading droplet on a wall. We previously developed a surface tension model using inter-particle force in the particle method; the static contact angle of droplets on the wall was verified at various contact angles, and the heights of droplets agreed well with those obtained theoretically. In this study, we applied our surface tension model to the simulation of a spreading droplet on a wall. The simulated dynamic contact angles for some Weber numbers were compared with those measured by Šikalo et al, and they agreed well. Our surface tension model was useful for simulating droplet motion under static and dynamic conditions.

The influence of proteins on calcium phosphate deposition over titanium implants studied by dynamic contact angle analysis and XPS

1997 ◽  
Vol 10 (2) ◽  
pp. 95-104 ◽  
Author(s):  
Ana Paula Valagão Amadeu do Serro ◽  
Anabela Catarino Fernandes ◽  
Benilde de Jesus ◽  
Vieira Saramago
Keyword(s):  
Contact Angle ◽  
Calcium Phosphate ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Titanium Implants ◽  
Contact Angle Analysis

Measurements of the Contact Angles for Various Fluids Which Are Widely Used in the Oilfields to Improve Oil Recovery

2018 ◽  
Author(s):  
M. Elsharafi ◽  
K. Vidal ◽  
R. Thomas
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Interfacial Tension ◽  
Oil Recovery ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Rock Face ◽  
Angle Measurements ◽  
Contact Angle Measurements

Contact angle measurements are important to determine surface and interfacial tension between solids and fluids. A ‘water-wet’ condition on the rock face is necessary in order to extract oil. In this research, the objectives are to determine the wettability (water-wet or oil-wet), analyze how different brine concentrations will affect the wettability, and study the effect of the temperature on the dynamic contact angle measurements. This will be carried out by using the Cahn Dynamic Contact Angle. Analyzer DCA 315 to measure the contact angle between different fluids such as surfactant, alkaline, and mineral oil. This instrument is also used to measure the surface properties such as surface tension, contact angle, and interfacial tension of solid and liquid samples by using the Wilhelmy technique. The work used different surfactant and oil mixed with different alkaline concentrations. Varying alkaline concentrations from 20ml to 1ml were used, whilst keeping the surfactant concentration constant at 50ml.. It was observed that contact angle measurements and surface tension increase with increased alkaline concentrations. Therefore, we can deduce that they are directly proportional. We noticed that changing certain values on the software affected our results. It was found that after calculating the density and inputting it into the CAHN software, more accurate readings for the surface tension were obtained. We anticipate that the surfactant and alkaline can change the surface tension of the solid surface. In our research, surfactant is desirable as it maintains a high surface tension even when alkaline percentage is increased.

Effect of Plasticizer of Sizing Agent on the Surface of Carbon Fibers and Interface of its Composites

2011 ◽  
Vol 337 ◽  
pp. 10-15 ◽  
Author(s):  
Huan Xia Zhang ◽  
Amin Cao ◽  
Yong Kang Luo ◽  
Li Wei
Keyword(s):  
Contact Angle ◽  
Carbon Fibers ◽  
Photoelectron Spectroscopy ◽  
Interfacial Shear Strength ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Interfacial Shear ◽  
X Ray ◽  
Physical Changes ◽  
Contact Angle Analysis

In this work, carbon fibers were sized with different plasticizer of sizing agent in order to improve the performances of carbon fibers and the interface of carbon fibers composites. The chemical and physical changes induced by the treatments on carbon fibers surface are examined using dynamic contact angle analysis test(DCAT) , X-ray photoelectron spectroscopy (XPS). The interfacial shear strength (IFSS) of CF/EP composites are analysised by micro-droplet test. At the same time, the wear resistance was also studied in order to understand the effect of the plasticizer of sizing agent on the carbon fibers. The study shows that the 3# sized carbon fiber has the better wetting and surface energy. XPS results reveal that the 3# samples show a significant increase in oxygen-containing groups, such as–C–OH, -COOH, -C–O–C- and -COOR. 3#sizing agent also show better interface adhesion between fibers and matrix and has better wear resistant properties.

Improved interfacial and impact properties of carbon fiber/epoxy composites through grafting hyperbranched polyglycerols on a carbon fiber surface

e-Polymers ◽  
2014 ◽  
Vol 14 (2) ◽  
pp. 145-150 ◽  
Author(s):  
Kaiqiang Sui ◽  
Qingbo Zhang ◽  
Yingying Liu ◽  
Lei Tan ◽  
Li Liu
Keyword(s):  
Contact Angle ◽  
Shear Strength ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Dynamic Contact Angle ◽  
Fiber Surface ◽  
Dynamic Contact ◽  
Impact Properties ◽  
Carbon Fiber Surface ◽  
Contact Angle Analysis

AbstractGrafting hyperbranched polyglycerols onto a carbon fiber surface is done in an attempt to improve the interfacial and impact properties between carbon fiber and epoxy resin. Scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and dynamic contact angle analysis were performed to characterize the carbon fibers. The TGA result shows that the mass fraction of the hyperbranched polyglycerols grafted onto the carbon fibers surface was 9.03%. The SEM results indicate that the hyperbranched polyglycerols have been grafted onto the carbon surface and that the surface roughness of the carbon fiber significantly increased. The XPS result indicates that oxygen-containing functional groups obviously increased after modification. Dynamic contact angle analysis indicates that the surface energy of modified carbon fibers increased significantly compared with the untreated ones. Results of the mechanical property tests show that interfacial shear strength increased from 59.86 to 80.16 MPa, interlaminar shear strength increased from 57.57 to 73.49 MPa and impact strength simultaneously increased from 2.52 to 3.52 J.

Dynamic Contact Angle Analysis of Silicone Hydrogel Contact Lenses

2010 ◽  
Vol 26 (1) ◽  
pp. 85-99 ◽  
Author(s):  
Michael Leonard Read ◽  
Philip Bruce Morgan ◽  
Jeremiah Michael Kelly ◽  
Carole Maldonado-Codina
Keyword(s):  
Contact Angle ◽  
Contact Lenses ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Silicone Hydrogel ◽  
Contact Angle Analysis
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