Controlled defects to link wetting properties to surface heterogeneity

Frosted glass is a common, low cost material. Its roughness can be used to control how it is wet by water. In this paper, the wetting properties of silicone oil and water are investigated. For the oil, wetting is total since the oleophilic character of the glass is enhanced by its roughness. Due to the remarkable optical properties of frosted glass, the spreading of oil droplets on its surface was recorded over three months. Frosted glass is a parahydrophilic surface because of its large contact angle hysteresis (up to 80° ). The behaviour of oil and water droplets was compared on a long piece of inclined frosted glass. The trajectories (and the spreading) of the droplets were studied and phenomenological laws were deduced to describe the dependence of the droplet speed on the initial volume of the droplet and the angle of inclination. Such dependences of speed at long travel distances (100 times the capillary length) were deduced and rationalised with a simple model that takes into account the thickness of the wake. Moreover, we analysed the flow inside the wake of water droplets sliding on inclined frosted glass. Suggestions are given on how to exploit drainage of the water droplet wake and the high hysteresis of water within the framework of open microfluidics.

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Adhesion force and Nanotribological Characteristics of Chemical Vapor Deposited Fluorocarbon Films

MRS Proceedings ◽

10.1557/proc-782-a5.55 ◽

2003 ◽

Vol 782 ◽

Cited By ~ 1

Author(s):

Nam-Kyun Kim ◽

Tae-Gon Kim ◽

Jin-Goo Park ◽

Woon-Bae Kim ◽

Hyung- Jae Shin

Keyword(s):

Contact Angle ◽

Adhesion Force ◽

Contact Angle Hysteresis ◽

Chemical Vapor ◽

Surface Heterogeneity ◽

Contact Angles ◽

Fluorocarbon Films ◽

Chemical Vapor Deposited ◽

Infra Red ◽

Coated Surfaces

ABSTRACTIn this study, Adhesion force and Nanotribological Characteristics of fluorocarbon (FC) films on Al deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) were evaluated. The contact angle of FC thin films on Al was measured to be around 110°. The surface energy was calculated to be 15 dynes/cm from the measurements of contact angles of polar and nonpolar solutions on surfaces. The contact angle hysteresis, which is an indicator for the surface heterogeneity, was lower than 30°. The friction force of FC films coated surfaces was three times lower than bare Al. The adhesion force of bare Al was measured to be around 9.6nN. The presence of FC films on Al reduced it to below 4nN. Fourier transform infra-red (FTIR) spectra showed the presence of fluorocarbon groups such as –CFn- and =CF=CF2.

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Towards optimization of patterned superhydrophobic surfaces

Journal of The Royal Society Interface ◽

10.1098/rsif.2006.0211 ◽

2007 ◽

Vol 4 (15) ◽

pp. 643-648 ◽

Cited By ~ 102

Author(s):

Bharat Bhushan ◽

Michael Nosonovsky ◽

Yong Chae Jung

Keyword(s):

Contact Angle ◽

Contact Angle Hysteresis ◽

Hydrophobic Surface ◽

Dimensional Parameter ◽

Wetting Properties ◽

Spacing Factor ◽

Composite Interface ◽

Experimental Values ◽

Solid Liquid Interface ◽

Solid Liquid

Experimental and theoretical study of wetting properties of patterned Si surfaces with cylindrical flat-top pillars of various sizes and pitch distances is presented. The values of the contact angle (CA), contact angle hysteresis (CAH) and tilt angle (TA) are measured and compared with the theoretical values. Transition from the composite solid–liquid–air to the homogeneous solid–liquid interface is investigated. It is found that the wetting behaviour of a patterned hydrophobic surface depends upon a simple non-dimensional parameter, the spacing factor, equal to the pillar diameter divided by the pitch. The spacing factor controls the CA, CAH and TA in the composite interface regime, as well as destabilization and transition to the homogeneous interface. We show that the assumption that the CAH is a consequence of the adhesion hysteresis and surface roughness leads to the theoretical values of the CAH that are in a reasonably good agreement with the experimental values. By decreasing the spacing factor, the values of CA=170°, CAH=5° and TA=3° are achieved. However, with further decreasing of the spacing factor, the composite interface destabilizes.

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Influence of Abrasive Load on Wettability and Corrosion Inhibition of a Commercial Superhydrophobic Coating

Coatings ◽

10.3390/coatings10090887 ◽

2020 ◽

Vol 10 (9) ◽

pp. 887

Author(s):

Arjun Manoj ◽

Rahul Ramachandran ◽

Pradeep L. Menezes

Keyword(s):

Contact Angle ◽

Corrosion Inhibition ◽

Mechanical Stability ◽

Electrochemical Impedance ◽

Contact Angle Hysteresis ◽

Open Circuit ◽

Superhydrophobic Coating ◽

Corrosion Properties ◽

Wetting Properties ◽

Before And After

The poor mechanical stability of hydrophobic and superhydrophobic surfaces and coatings severely hinder their commercial and industrial applicability. In addition to being expensive and time-consuming to manufacture, the ability of these coatings to maintain their non-wetting properties after mechanical abrasion and wear is currently not well-understood. In this work, the influence of increasing abrasive loads on the roughness, wettability, and corrosion inhibition properties of a commercial superhydrophobic coating was studied. It was shown that the wetting and corrosion properties of the superhydrophobic coating was affected by the abrasive load. Increasing abrasive loads were applied using a tribometer and the electrochemical response was studied using open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy. The wetting and roughness behavior of the coating before and after the application of the abrasive load was characterized using contact angle, contact angle hysteresis, and optical profilometry. The protective properties of the superhydrophobic coating was observed to deteriorate as the abrasive load increased. Similarly, after a specific abrasive load, the coating transitioned from the Cassie-Baxter state of wetting into that of the Wenzel state.

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Wetting Properties of Polyetheretherketone Plasma Activated and Biocoated Surfaces

Colloids and Interfaces ◽

10.3390/colloids3010040 ◽

2019 ◽

Vol 3 (1) ◽

pp. 40 ◽

Cited By ~ 4

Author(s):

Kacper Przykaza ◽

Klaudia Woźniak ◽

Małgorzata Jurak ◽

Agnieszka Wiącek

Keyword(s):

Contact Angle ◽

Free Energy ◽

Surface Free Energy ◽

Contact Angle Hysteresis ◽

Biologically Active ◽

Adhesive Properties ◽

Surface Sterilization ◽

Wetting Properties ◽

Angle Measuring ◽

Modified Surface

Polyetheretherketone (PEEK) biomaterial is a polymer which has been widely used since the early 90s as a material for human bone implant preparations. Nowadays it is increasingly used due to its high biocompatibility and easily modeling, as well as better mechanical properties and price compared to counterparts made of titanium or platinum alloys. In this paper, air low-temperature and pressure plasma was used to enhance PEEK adhesive properties as well as surface sterilization. On the activated polymeric carrier, biologically-active substances have been deposited with the Langmuir-Blodgett technique. Thereafter, the surface was characterized using optical profilometry, and wettability was examined by contact angle measuring. Next, the contact angle hysteresis (CAH) model was used to calculate the surface free energy of the modified surface of PEEK. The variations of wettability and surface free energy were observed depending on the deposited monolayer type and its components.

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