Anti-Icing Property of the Prepared Super-Hydrophobic Octadecyltrichlorosilane (OTS) Film by Phase Separation Method

2013 ◽  
Vol 663 ◽  
pp. 331-334
Author(s):  
Liang Ge ◽  
Jin Yuan Yao ◽  
Hong Wang ◽  
Gui Fu Ding
Keyword(s):  
Contact Angle ◽  
Phase Separation ◽  
Heterogeneous Nucleation ◽  
Hydrophobic Surface ◽  
Separation Method ◽  
Surface Wettability ◽  
Nucleation Theory ◽  
Ice Formation ◽  
Water Droplets ◽  
Hydrophobic Surfaces

In this paper, we prepared an octadecyltrichlorosilane(OTS) super-hydrophobic film using phase separation method to demonstrate the anti-icing property of super-hydrophobic surfaces. We investigated the super-hydrophobicity of the surface in -5°C environment, as well as the icing process of water droplets on the surface which proceeded at the temperature low to -15°C. We found that the prepared OTS film retained its super-hydrophobicity in the -5°C environment by the measurement of contact angle. It was observed that the icing progress of water droplets on the super-hydrophobic surface was greatly retarded. Based on the classical heterogeneous nucleation theory, it concluded that the ice formation is directly related to the surface wettability. This research would be beneficial to the preparation of anti-icing films.

scholarly journals Anti-Icing Property of Superhydrophobic Octadecyltrichlorosilane Film and Its Ice Adhesion Strength

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Liang Ge ◽  
Guifu Ding ◽  
Hong Wang ◽  
Jinyuan Yao ◽  
Ping Cheng ◽  
...  
Keyword(s):  
Contact Angle ◽  
Phase Separation ◽  
Adhesion Strength ◽  
Separation Method ◽  
Superhydrophobic Surfaces ◽  
Water Droplets ◽  
Ice Adhesion

An octadecyltrichlorosilane (OTS) superhydrophobic film using phase-separation method was prepared to demonstrate the anti-icing property of superhydrophobic surfaces. The superhydrophobicity of the film at −5∘Cwas investigated. It was found that the prepared OTS film retained its superhydrophobicity at −5∘Cby the measurement of contact angle and roll-off angle. The icing progress of water droplets on the surface at −15∘Cwas observed. It showed that the prepared OTS film can markedly retard the icing process of water droplets and dramatically decrease the ice adhesion strength compared with that of blank surface, which can be used as anti-icing surfaces.

scholarly journals Stretchable Hydrophobic Surfaces and Self-Cleaning Applications

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bekir Sami Yilbas ◽  
Ghassan Hassan ◽  
Hussain Al-Qahtani ◽  
Naser Al-Aqeeli ◽  
Abdullah Al-Sharafi ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Droplet ◽  
Dust Removal ◽  
Dust Particles ◽  
Mass Ratio ◽  
Water Droplets ◽  
Surface Wetting ◽  
Hydrophobic Surfaces ◽  
Removal Mechanisms ◽  
Nano Size

Abstract Hydrophobizing of stretchable elastomer surfaces is considered and the reversible behavior of the resulting surface wetting state is examined after stretching and relaxing the hydrophobized samples. The environmental dust are analyzed in terms of elemental constitutes and size, and the dust pinning on the hydrophobized surface is measured. The dust removal mechanisms, by the water droplets on the hydrophobized surface, are investigated. We demonstrated that deposition of functionalized nano-size silica units on the elastomer surface gives rise to hydrophobicity with 135° ± 3° contact angle and low hysteresis of 3° ± 1°. Stretching hydrophobized elastomer surface by 50% (length) reduces the contact angle to 122° ± 3° and enhances the hysteresis to 6° ± 1°. However, relaxing the stretched sample causes exchanging surface wetting state reversibly. Water droplet rolling and sliding can clean the dusty hydrophobized surface almost 95% (mass ratio of the dust particles removed). Droplet puddling causes striations like structures along the droplet path and close examination of the few residues of the dust reveals that the droplet takes away considerably large amount of dust from surface.

Effects of Titanium Surface Wettability on Osteoblast Behavior In Vitro

2020 ◽  
Vol 985 ◽  
pp. 64-68
Author(s):  
Kenta Nisogi ◽  
Satoshi Okano ◽  
Sengo Kobayashi ◽  
Kensuke Kuroda ◽  
Takeaki Okamoto
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Titanium Surface ◽  
Pure Titanium ◽  
Hydrophobic Surface ◽  
Surface Wettability ◽  
In Vitro Assays ◽  
Water Contact ◽  
Heat Treated

Surface wettability is thought to influence the osteoconductivity of bone-substituting materials; however, the effects of surface wettability on osteoblast behavior are not well understood. In this study, we prepared both an as-polished pure titanium with a water contact angle (WCA) of 57° and heat-treated pure titanium with more hydrophobic surface and WCAs of 68°-98°. The effects of the surface wettability of pure titanium on osteoblast behaviors were evaluated by in vitro assays. Compared with the as-polished titanium, the proliferation rate of osteoblast increased on heat-treated titanium. This suggested that surface wettability affects osteoblast behaviors, meaning osteoconductivity is influenced by surface wettability.

Contact Angle of Water Droplets in a High-Temperature, High-Pressure Environment

2004 ◽  
Author(s):  
Tsukasa Hayashi ◽  
Tatsuya Hazuku ◽  
Tomoji Takamasa ◽  
Kenrou Takamori
Keyword(s):  
Contact Angle ◽  
High Pressure ◽  
High Temperature ◽  
Contact Angles ◽  
Surface Wettability ◽  
Water Droplets ◽  
Straight Line ◽  
Angle Condition ◽  
High Pressure Environment ◽  
High Temperature High Pressure

This paper presents an experimental study of surface wettability on a stainless plate in a high-temperature, high-pressure environment. Using a pressure vessel, we measured contact angles of water droplets at temperatures from 20 to 300°C and a constant pressure of 15 MPa, as an indicator of macroscopic surface wettability. Measured contact angles decreased with temperature below 250°C, clustering around a straight line at temperatures below 120°C and around another line in the range from 120 to 250°C. At temperatures above 250°C, on the other hand, the contact angles remained constant, independent of temperature, and contrary to the existing theoretical model, no highly hydrophilic condition or null contact angle condition was achieved.

Superhydrophobic Surfaces Properties for Anti-Icing

2011 ◽  
Author(s):  
Mohammad Amin Sarshar ◽  
Christopher Swarctz ◽  
Scott Hunter ◽  
John Simpson ◽  
Chang-Hwan Choi
Keyword(s):  
Contact Angle ◽  
Wind Tunnel ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Superhydrophobic Surfaces ◽  
Ice Formation ◽  
Flow Conditions ◽  
Water Droplets ◽  
Dynamic Flow ◽  
Static Contact

In this paper, the iceophobic properties of superhydrophobic surfaces are compared to those of uncoated aluminum and steel plate surfaces as investigated under dynamic flow conditions by using a closed loop low-temperature wind tunnel. Superhydrophobic surfaces were prepared at the Oak Ridge National Laboratory by coating aluminum and steel plates with nano-structured hydrophobic particles. The contact angle and contact angle hysteresis measured for these surfaces ranged from 165–170° and 1–8°, respectively. The superhydrophobic plates along with uncoated control ones were exposed to an air flow of 12 m/s and 20°F with micron-sized water droplets in the icing wind tunnel and the ice formation and accretion were probed by using high speed cameras for 90 seconds. Results show that the developed superhydrophobic coatings significantly delay the ice formation and accretion even with the impingement of accelerated super-cooled water droplets, but there is a time scale for this phenomenon which has a clear relation with contact angle hysteresis of the samples. Among the different superhydrophobic coating samples, the plate having the lowest contact angle hysteresis showed the most pronounced iceophobic effects, while the correlation between static contact angles and the iceophobic effects was not evident. The results suggest that the key parameter for designing iceophobic surfaces is to retain a low contact angle hysteresis, rather than to have only a low contact angle, which can result in more efficient anti-icing properties in dynamic flow conditions.

Hydrophobicity of Surfaces Coated with Functionalized Titanium Dioxide Nanoparticles

2016 ◽  
Vol 705 ◽  
pp. 268-272 ◽  
Author(s):  
Paul Albert L. Sino ◽  
Marvin U. Herrera ◽  
Mary Donnabelle L. Balela
Keyword(s):  
Contact Angle ◽  
Silicon Carbide ◽  
Titanium Dioxide ◽  
Titanium Dioxide Nanoparticles ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Water Droplets ◽  
Hydrophobic Surfaces ◽  
Coated Surface ◽  
Self Cleaning

Hydrophobic surfaces are eyed for their self-cleaning ability because water droplets can roll on them (instead of clinging), thus the surface have capability to remove dirt. Hydrophobic surfaces were created by coating functionalized Titanium Dioxide-based paint. The paint was fabricated by reacting fluorosilane molecules in ethanol with titanium dioxide nanoparticles. Ethanol also serves as the volatile suspension medium that evaporates when the paint is coated on surfaces. The paint was coated on different surfaces by simple dipping. Contact angle of coated aluminum sheet, soda-lime glass, filter paper and silicon carbide polishing paper showed hydrophobicity. Water droplets are made to roll on coated soda-lime glass at angle of 0.057°. The ability of water droplets to roll highlights the coated surface self-cleaning potential.

scholarly journals Polyurethanes from modified castor oil and chitosan

2017 ◽  
Vol 50 (5) ◽  
pp. 419-434 ◽  
Author(s):  
Said Arévalo-Alquichire ◽  
Claudia Ramírez ◽  
Laura Andrade ◽  
Yomaira Uscategui ◽  
Luis E Diaz ◽  
...  
Keyword(s):  
Contact Angle ◽  
Phase Separation ◽  
Cell Viability ◽  
Castor Oil ◽  
Degradation Products ◽  
Hydrophobic Surface ◽  
In Vitro Degradation ◽  
Hydroxyl Value ◽  
Solid Polymers

Polyurethanes (PUs) from castor oil (CO), modified CO (MCO) by transesterification reaction, isophorone diisocyanate (IPDI) in an NCO/OH ratio equal to 1, and chitosan (CS) were synthesized to assess their potential as biomaterials. PUs were characterized by Fourier transform infrared spectroscopy, hydroxyl value (ASTM D1957), thermogravimetric analysis, Shore A hardness (ASTM D2240), and scanning electronic microscopy (SEM). Also, contact angle, water retention and in vitro degradation in PBS, and cell viability on fibroblast were performed. The hydroxyl value confirms CO modification, and IR analysis confirms urethane bond formation. The thermal assay does not show new degradation stages and polyol with a high functionality had better hardness performance due to the increase in cross-linking. The micrograph shows micro-phase separation of both polymers. The contact angle shows the hydrophobic surface with an angle over 65°, and the CS and polyol type do not affect swelling and in vitro degradation due to phase separation between both polymers. The cell viability was over 70% in all cases, and solid polymers and degradation products involve non-cytotoxic effects on the samples. The results suggest a potential for these formulations in the biomedical field.

Comparing Electrowettability and Surfactants As Tools for Wettability Enhancement on a Hydrophobic Surface

2019 ◽  
Author(s):  
Manojkumar Lokanathan ◽  
Himanshu Sharma ◽  
Mostafa Shabaka ◽  
Vaibhav Bahadur ◽  
Kishore Mohanty
Keyword(s):  
Contact Angle ◽  
Electric Fields ◽  
Energy Production ◽  
Electrical Potential ◽  
Hydrophobic Surface ◽  
Contact Angles ◽  
Wettability Alteration ◽  
Electrical Potential Difference ◽  
Water Droplets ◽  
Zwitterionic Surfactants

Abstract Wettability alteration has significant applications in microfluidics, energy production and process engineering. Surfactants have been widely used for wettability alteration on surfaces. More recently, electrowetting (EW) has emerged as a powerful microfluidic technique to dynamically alter wettability. EW relies on the application of an electrical potential difference across a dielectric layer on which the fluid rests. This work analyzes the extent of wettability enhancement of water droplets on a hydrophobic surface (in air) via the use of surfactants and EW. Nine surfactants were chosen from the categories of anionic, cationic and zwitterionic surfactants. The critical micelle concentration (CMC) of these surfactants, and the wettability of surfactant-infused water droplets was measured at post and pre-CMC concentrations. Next, experiments were conducted to quantify the wettability enhancement of water droplets (with surfactants) via EW. Many interesting insights on the interplay between surfactants and electric fields are uncovered in this work. As expected, adding surfactants enhances wettability up to the CMC. EW can further enhance wettability of surfactant solutions and further reduce the contact angle by as much as 30°. Interestingly, it is seen that the influence of EW in enabling CA reduction is reduced by the addition of surfactants at pre-CMC levels. Conversely, surfactants strengthen the influence of EW at higher concentrations. It is noted that the extent of wettability alteration via EW is limited by the phenomena of contact angle saturation, wherein the contact angle saturates beyond a certain voltage. Interestingly, it is seen that at post CMC concentrations, the saturation contact angles are independent of surfactant concentrations.

Temperature Dependence of the Contact Angle of Water on a Hydrophobic Surface at Pressurized Condition

2020 ◽  
Author(s):  
Jia-Wen Song ◽  
Meng-Chen Ma ◽  
Li-Wu Fan
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Temperature Dependence ◽  
Sessile Drop ◽  
Hydrophobic Surface ◽  
Contact Angles ◽  
Surface Wettability ◽  
Surface Thermodynamics ◽  
Temperature Spectrum ◽  
Phase Change Heat Transfer

Abstract It is of both practical and scientific significance to study the temperature dependence of contact angles, towards development of surface wettability manipulation techniques for enhanced phase change heat transfer as well as the theoretical estimation of solid interfacial energy. However, the variations of surface wettability of a hydrophobic solid with altering temperature remain unclear. In this work, in situ characterizations of the contact angle of water on Teflon (PTFE) surfaces as well as the surface tension of water over a temperature spectrum from ∼25 °C to 160 °C at pressurized condition (2 MPa) were conducted by employing the sessile drop and pendant drop methods, respectively. A nearly invariant trend of the contact angle of water was observed over the entire temperature range. Moreover, it was shown that the surface tension of water linearly declines with raising the temperature. Based on the theory of surface thermodynamics, the effects of temperature on the contact angles were analyzed with the variations of interfacial tensions.

Corrosion resistance and mechanism of micro-nano structure super-hydrophobic surface prepared by laser etching combined with coating process

2019 ◽  
Vol 66 (3) ◽  
pp. 264-273 ◽  
Author(s):  
Qianqian Zhang ◽  
Huichen Zhang
Keyword(s):  
Contact Angle ◽  
Corrosion Resistance ◽  
Magnesium Alloys ◽  
Hydrophobic Surface ◽  
Static Contact Angle ◽  
Laser Etching ◽  
Hydrophobic Surfaces ◽  
Nano Structure ◽  
Content Type ◽  
Static Contact

Purpose The purpose of this paper is to evaluate the effect of micro-nano mixed super-hydrophobic structure on corrosion resistance and mechanism of magnesium alloys. Design/methodology/approach A super-hydrophobic surface was fabricated on AZ91 and WE43 magnesium alloys by laser etching and micro-arc oxidation (MAO) with SiO2 nanoparticles coating and low surface energy material modification. The corrosion resistance properties of the prepared super-hydrophobic surfaces were studied based on polarization curves and immersion tests. Findings Compared with bare substrates, the corrosion resistance of super-hydrophobic surfaces was improved significantly. The corrosion resistance of super-hydrophobic surface is related to micro-nano composite structure, static contact angle and pretreatment method. The more uniform the microstructure and the larger the static contact angle, the better the corrosion resistance of the super-hydrophobic surface. The corrosion resistance of super-hydrophobic by MAO is better than that of laser machining. Corrosion of super-hydrophobic surface can be divided into air valley action, physical shielding, pretreatment layer action and substrate corrosion. Originality/value The super-hydrophobic coatings can reduce the contact of matrix with water so that a super-hydrophobic coating would be an effective way for magnesium alloy anti-corrosion. Therefore, the corrosion resistance properties and mechanism of the prepared super-hydrophobic magnesium alloys were investigated in detail.

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