scholarly journals Fabrication of Superhydrophobic Nanocomposite Coatings Using Polytetrafluoroethylene and Silica Nanoparticles

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Bharathibai J. Basu ◽  
V. Dinesh Kumar
Keyword(s):  
Cost Effective ◽  
High Water ◽  
Nanocomposite Coatings ◽  
Sliding Angle ◽  
Electron Microscopic ◽  
Water Contact ◽  
Superhydrophobic Coatings ◽  
Low Surface Energy ◽  
Hydrophobically Modified ◽  
Superhydrophobic Property

Superhydrophobic nanocomposite coatings were fabricated by incorporating hydrophobically modified silica (HMS) nanoparticles in polytetrafluoroethylene (PTFE) emulsion. Hydrophobicity of the coating was dependent on the concentration of HMS. Coatings containing optimum amounts of PTFE and HMS exhibited superhydrophobic property with high water contact angle (WCA) of 165∘ and low sliding angle <2∘. Scanning electron microscopic (SEM) studies have shown a binary surface topography composed of microbumps and nanoscale granules. The synergistic effect of the micro-nano-binary structure and low surface energy of PTFE was responsible for the superhydrophobicity of the coating. The method is simple and cost-effective and can be used for preparing self-cleaning superhydrophobic coatings on large areas of different kinds of substrates like glass, metal, and composites.

scholarly journals Improving the Hydrophobicity of ZnO by PTFE Incorporation

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Meenu Srivastava ◽  
Bharathi Bai J. Basu ◽  
K. S. Rajam
Keyword(s):  
Thermal Treatment ◽  
Stearic Acid ◽  
Superhydrophobic Surface ◽  
Cost Effective ◽  
Electrical Energy ◽  
High Water ◽  
Superhydrophobic Coating ◽  
Water Contact ◽  
Low Surface Energy ◽  
Effective Manner

The objective of the present study is to obtain a zinc oxide- (ZnO-) based superhydrophobic surface in a simple and cost-effective manner. Chemical immersion deposition being simple and economical has been adopted to develop modified ZnO coating on glass substrate. Several modifications of ZnO like treatment with alkanoic acid (stearic acid) and fluoroalkylsilane to tune the surface wettability (hydrophobicity) were attempted. The effect of thermal treatment on the hydrophobic performance was also studied. It was observed that thermal treatment at 70°C for 16 hrs followed by immersion in stearic acid resulted in high water contact angle (WCA), that is, a superhydrophobic surface. Thus, a modified ZnO superhydrophobic surface involves the consumption of large amount of electrical energy and time. Hence, the alternate involved the incorporation of low surface energy fluoropolymer polytetrafluoroethylene (PTFE) in the ZnO coating. The immersion deposited ZnO-PTFE composite coating on modification with either stearic acid or fluoroalkylsilane resulted in a better superhydrophobic surface. The coatings were characterized using Scanning Electron Microscope (SEM) for the surface morphology. It was found that microstructure of the coating was influenced by the additives employed. A flower-like morphology comprising of needle-like structure arranged in a radial manner was exhibited by the superhydrophobic coating.

scholarly journals Synthesis and Properties of Electrodeposited Ni–Co/WS2 Nanocomposite Coatings

Coatings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 148 ◽  
Author(s):  
Yang He ◽  
Shuncai Wang ◽  
Wanting Sun ◽  
Philippa Reed ◽  
Frank Walsh
Keyword(s):  
Friction Coefficient ◽  
High Water ◽  
Nanocomposite Coatings ◽  
Low Friction ◽  
One Pot ◽  
Water Contact ◽  
Good Oxidation Resistance ◽  
Low Surface Energy ◽  
Coated Surfaces

Ni–Co coatings have gained widespread attention due to their potential in replacing hard chromium deposits (which have traditionally utilized toxic and corrosive chromic acid baths). A major challenge is to lower the high coefficient of friction of coated surfaces against steel, under dry sliding conditions. In this research, low friction Ni–Co/WS2 nanocomposite coatings have been prepared by a convenient, one-pot electrodeposition from aqueous Ni–Co plating baths containing WS2 particles. The embedment of the WS2 lubricants is found to reduce the friction coefficient of coating significantly, and an ultra-low friction coefficient of 0.16 is obtained for the coating having a WS2 content of 7.1 wt.%. Morphology and composition characterization of wear tracks reveal that the formation of a WS2-rich lubricating tribofilm on the contact surfaces is beneficial to a low friction coefficient and good oxidation resistance. The wettability of electrodeposited coatings was also investigated. Compared to pure Ni-Co coating, the Ni–Co/7.1 wt.% WS2 coating has an excellent hydrophobicity with a high water contact angle (WCA) of 157°, due to a rough surface with dual scale protrusions and the low surface energy of WS2.

scholarly journals Superhydrophobic Self-Assembled Silane Monolayers on Hierarchical 6082 Aluminum Alloy for Anti-Corrosion Applications

2020 ◽  
Vol 10 (8) ◽  
pp. 2656 ◽  
Author(s):  
Amani Khaskhoussi ◽  
Luigi Calabrese ◽  
Edoardo Proverbio
Keyword(s):  
Aluminum Alloy ◽  
Surface Energy ◽  
High Water ◽  
Dip Coating ◽  
Aluminum Surface ◽  
Sliding Angle ◽  
Water Contact ◽  
Electrochemical Tests ◽  
Self Assembled ◽  
6082 Aluminum Alloy

In this work, a two-stage methodology to design super-hydrophobic surfaces was proposed. The first step consists of creating a rough nano/micro-structure and the second step consists of reducing the surface energy using octadecyltrimethoxysilane. The surface roughening was realized by three different short-term pretreatments: (i) Boiling water, (ii) HNO3/HCl etching, or (iii) HF/HCl etching. Then, the surface energy was reduced by dip-coating in diluted solution of octadecyltrimethoxysilane to allow the formation of self-assembled silane monolayers on a 6082-T6 aluminum alloy surface. Super-hydrophobic aluminum surfaces were investigated by SEM-EDS, FTIR, profilometry, and contact and sliding angles measurements. The resulting surface morphologies by the three approaches were structured by a dual hierarchical nano/micro-roughness. The surface wettability varied with the applied roughening pretreatment. In particular, an extremely high water contact angle (around 180°) and low sliding angle (0°) were evidenced for the HF/HCl-etched silanized surface. The results of electrochemical tests demonstrate a remarkable enhancement of the aluminum alloy corrosion resistance through the proposed superhydrophobic surface modifications. Thus, the obtained results evidenced that the anti-wetting behavior of the aluminum surface can be optimized by coupling an appropriate roughening pretreatment with a self-assembled silane monolayer deposition (to reduce surface energy) for anticorrosion application.

Preparation and Properties Fluoralkylpolysiloxane Modified Polyurethane Films

2009 ◽  
Vol 620-622 ◽  
pp. 741-744 ◽  
Author(s):  
Rui Weng ◽  
Chong Rui Wang ◽  
Lian Meng Zhang ◽  
Shui Ping Wang
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Silicone Oil ◽  
Soft Segment ◽  
High Water ◽  
Water Contact ◽  
Sulfuryl Fluoride ◽  
Low Surface Energy ◽  
End Capping ◽  
Amino Silicone

Fluoralkylpolysiloxane modified Polyurethane (FSPU) films with high water contact angle (CA) were prepared. fluoralkylpolysiloxane was obtained using perfluoro octyl sulfuryl fluoride and terminal amino-silicone oil as reactants. Then, the isocyanate end capped PU prepolymer was synthesized by reacting isocyanate with a soft segment mixed by active amino-end-capping fluoralkylpolysiloxane and polyether glycol. The fluoralkylpolysiloxane modified PU films were obtained after the PU prepolymer was cured by 3,3 '- dichloro -4,4' – amino - diphenyl methane (MOCA). The results showed that the modified polyurethane with 10% (mass fraction) PFATPS had a good compatibility, low surface energy, surface water contact angle and surface oil contact angle was improved by 49° and 37° respectively, and heat resistance, water resistance was apparently improved.

Fabrication and Characterization of a Superhydrophobic Low-Density Polyethylene Film

2012 ◽  
Vol 557-559 ◽  
pp. 1834-1837
Author(s):  
Jun Liang Wu ◽  
Hui Ping Zhang ◽  
Xu Nan Wang
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Energy Materials ◽  
Water Contact ◽  
Simple Method ◽  
Ldpe Film ◽  
Low Surface Energy ◽  
Special Surface ◽  
Superhydrophobic Property

A superhydrophobic LDPE film was obtained by a simple method in atmosphere without addition of low-surface-energy materials. The water contact angle of the superhydrophobic LDPE film are 155±1.9º. SEM shows that compared with common smooth LDPE film, a porous structure was obviously observed on the superhydrophobic LDPE film. Such a special surface microstructure may result in the superhydrophobic property. The effect of drying temperature and concentration on water contact angle were studied.

Organic-inorganic composite nanocoatings with superhydrophobicity and thermal stability

2018 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
A. Syafiq ◽  
A.K. Pandey ◽  
Vengadaesvaran Balakrishnan ◽  
Syed Shahabuddin ◽  
Nasrudin Abd Rahim
Keyword(s):  
Thermal Stability ◽  
Surface Roughness ◽  
Glass Substrate ◽  
Alkyl Chain ◽  
Sol Gel ◽  
High Thermal Stability ◽  
Sliding Angle ◽  
Water Contact ◽  
Content Type ◽  
Superhydrophobic Coatings

Purpose This paper aims to investigate the thermal stability and hydrophobicity of difference alkyl chain of silanes with silicon (Si) micro- and nanoparticles. Design/methodology/approach Sol-gel methods have been used to design superhydrophobic glass substrates through surface modification by using low-surface-energy Isooctyl trimethoxysilane (ITMS) and Ethyl trimethoxysilane (ETMS) solution. Hierarchical double-rough scale solid surface was built by Si micro- and nanoparticles to enhance the surface roughness. The prepared sol was applied onto glass substrate using dip-coating method and was dried at control temperature of 400°C inside the tube furnace. Findings The glass substrate achieved the water contact angle as high as 154 ± 2° and 150.4 ± 2° for Si/ITMS and Si/ETMS films, respectively. The Si/ITMS and Si/ETMS also were equipped with low sliding angle as low as 3° and 5°, respectively. The Si micro- and nanoparticles in the coating system have created nanopillars between them, which will suspend the water droplets. Both superhydrophobic coatings have showed good stability against high temperature up to 200°C as there are no changes in WCA shown by both coatings. Si/ITMS film sustains its superhydrophobicity after impacting with further temperature up to 400°C and turns hydrophobic state at 450°C. Research limitations/implications Findings will be useful to develop superhydrophobic coatings with high thermal stability. Practical implications Sol method provides a suitable medium for the combination of organic-inorganic network to achieve high hydrophobicity with optimum surface roughness. Originality/value Application of different alkyl chain groups of silane resin blending with micro- and nanoparticles of Si pigments develops superhydrophobic coatings with high thermal stability.

Micro-Nanostructured Silicone Rubber Surfaces Using Compression Molding

2018 ◽  
Vol 941 ◽  
pp. 1802-1807 ◽  
Author(s):  
Khosrow Maghsoudi ◽  
Gelareh Momen ◽  
Reza Jafari ◽  
Masoud Farzaneh ◽  
Tony Carreira
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Silicone Rubber ◽  
Surface Characterization ◽  
Contact Angle Hysteresis ◽  
Compression Molding ◽  
Sliding Angle ◽  
Water Contact ◽  
Superhydrophobic Property ◽  
Aluminum Surfaces

A facile method is introduced for production of micro-nanostructured silicone rubber surfaces by means of direct replication using a compression molding system. The fabricated samples possessing surface roughness display water contact angle of more than 160o and contact angle hysteresis (CAH) and sliding angle of less than 5o. Such low surface wettability of silicone specimens verifies the induced superhydrophobic property. Chemically etched aluminum surfaces could work excellently as templates whose patterns were replicated on the rubber surfaces successfully. Various etching conditions were examined. Surface characterization techniques revealed the presence of micro-nanostructures on the produced silicone surfaces.

scholarly journals High Stability Performance of Superhydrophobic Modified Fluorinated Graphene Films on Copper Alloy Substrates

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Rafik Abbas ◽  
N. Elkhoshkhany ◽  
Ahmed Hefnawy ◽  
Shaker Ebrahim ◽  
Aya Rahal
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Sliding Angle ◽  
Water Contact ◽  
Stability Performance ◽  
Graphene Films ◽  
Superhydrophobic Property ◽  
Self Cleaning ◽  
Fluorinated Graphene ◽  
Highly Hydrophobic

A stable self-cleaning superhydrophobic modified fluorinated graphene surface with micro/nanostructure was successfully fabricated on copper substrates via drop coating process. Irregularly stacked island-like multilayered fluorinated graphene nanoflakes comprised the microstructure. The fabricated films exhibited outstanding superhydrophobic property with a water contact angle 167° and water sliding angle lower than 4°. The developed superhydrophobic surface showed excellent corrosion resistance with insignificant decrease of water contact angle 166° in 3.5 wt.% NaCl solution. This stable highly hydrophobic performance of the fluorinated graphene films could be useful in self-cleaning, antifogging, corrosion resistive coatings and microfluidic devices.

scholarly journals Functional Superhydrophobic Coating Systems for Possible Corrosion Mitigation

2020 ◽  
Vol 14 (2) ◽  
pp. 148-158 ◽  
Author(s):  
Sarah F. Jurak ◽  
◽  
Emil F. Jurak ◽  
Md. Nizam Uddin ◽  
Ramazan Asmatulu
Keyword(s):  
Sol Gel ◽  
Chemical Vapor ◽  
Layer By Layer ◽  
Superhydrophobic Coating ◽  
Sliding Angle ◽  
One Pot ◽  
Water Contact ◽  
Superhydrophobic Coatings ◽  
Run Off ◽  
Self Cleaning

Because of their repellent, corrosion-mitigating, anti-icing, and self-cleaning properties, superhydrophobic coatings have numerous applications from windshields to textiles. A superhydrophobic coating is defined as one having a water contact angle (WCA) greater than 150° with a surface sliding angle less than 10°, and very low hysteresis between the advancing and receding angles. Its surface exhibits the so-called “lotus leaf effect,” whereby water bounces and balls up on contact. Here, water droplets run off readily, taking along dirt and dust for a self-cleaning effect that keeps the surface dry. The chemical composition of a surface affects the WCA, which can rise to 120°, but to achieve a WCA greater than 150°, which is considered superhydrophobic, an additional micro- and nanostructural component is needed. This functional hierarchical micro- and nanomorphology is exhibited in nature by plants and insects. A superhydrophobic coating on metallic substrates promises to provide corrosion mitigation by blocking oxygen and electrolytes, which are needed for the initiation of corrosion at the surface and interface. The methods used for preparing functional superhydrophobic coatings include sol-gel processing, layer-by-layer assembly, etching, lithography, chemical and electrochemical depositions, chemical vapor deposition, electrospinning, hydrothermal synthesis, and one-pot reactions. In this work, some research studies conducted to develop robust and durable superhydrophobic coatings are discussed in detail and analyzed for possible corrosion mitigation on the surfaces of metals and alloys. Scientists, engineers, students, and other participants in automotive, aircraft, energy, defense, electronics, and other industries will benefit greatly from this work.

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