scholarly journals Functional and versatile superhydrophobic coatings via stoichiometric silanization

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lishen Zhang ◽  
Alvin G. Zhou ◽  
Brigitta R. Sun ◽  
Kennedy S. Chen ◽  
Hua-Zhong Yu
Keyword(s):  
Real Life ◽  
Functional Materials ◽  
Single Step ◽  
Sliding Angle ◽  
Solid Materials ◽  
Water Contact ◽  
Superhydrophobic Coatings ◽  
Coating Mixture ◽  
Industrial Solvents ◽  
Nanoscale Roughness

AbstractSuperhydrophobic coatings have tremendous potential for applications in different fields and have been achieved commonly by increasing nanoscale roughness and lowering surface tension. Limited by the availability of either ideal nano-structural templates or simple fabrication procedures, the search of superhydrophobic coatings that are easy to manufacture and are robust in real-life applications remains challenging for both academia and industry. Herein, we report an unconventional protocol based on a single-step, stoichiometrically controlled reaction of long-chain organosilanes with water, which creates micro- to nano-scale hierarchical siloxane aggregates dispersible in industrial solvents (as the coating mixture). Excellent superhydrophobicity (ultrahigh water contact angle >170° and ultralow sliding angle <1°) has been attained on solid materials of various compositions and dimensions, by simply dipping into or spraying with the coating mixture. It has been demonstrated that these complete waterproof coatings hold excellent properties in terms of cost, scalability, robustness, and particularly the capability of encapsulating other functional materials (e.g. luminescent dyes).

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.

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.

scholarly journals Silica Based Superhydrophobic Nanocoatings for Natural Rubber Surfaces

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Veromee Kalpana Wimalasiri ◽  
Helapiyumi Uthpala Weerathunga ◽  
Nilwala Kottegoda ◽  
Veranja Karunaratne
Keyword(s):  
Natural Rubber ◽  
Imaging Techniques ◽  
Spray Coating ◽  
Surface Functional Groups ◽  
Sliding Angle ◽  
Water Contact ◽  
Force Microscopy ◽  
Superhydrophobic Coatings ◽  
Atomic Force ◽  
Coating Methods

Silica based nonfluorinated superhydrophobic coatings for natural rubber surfaces have been developed. The coating was synthesized using nanosilica dispersion and a polychloroprene type binder as a compatibilizer. This nanocoating of silica was applied on to the surface of finished natural rubber gloves, by spray coating or dipped coating methods. The nanocoating demonstrates a water contact angle of more than 150° and sliding angle of 7°. The morphological features of the coating have been studied using scanning electron microscopy and atomic force microscopy while Fourier transform infrared spectroscopy was used to understand the nature of surface functional groups. Both imaging techniques provided evidence for the presence of nanosized particles in the coating. Coated gloves demonstrated comparable mechanical properties and significantly better alcohol resistivity when compared to those of the uncoated gloves.

scholarly journals Stable and Durable Conductive Superhydrophobic Coatings Prepared by Double-Layer Spray Coating Method

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1506
Author(s):  
Xiang Liu ◽  
Kai Chen ◽  
Dekun Zhang ◽  
Zhiguang Guo
Keyword(s):  
Composite Coating ◽  
Double Layer ◽  
Low Cost ◽  
Spray Coating ◽  
Sliding Angle ◽  
Water Contact ◽  
Superhydrophobic Coatings ◽  
Coating Method ◽  
Specialty Fields ◽  
Application Fields

Herein, a low cost, durable, and stable conductive superhydrophobic composite coating (CSC coating) was fabricated on a Q345 steel surface by simple double-layer spray coating. The water contact angle (WCA) of the CSC coating was 160° and the sliding angle (SA) was 3°. In addition to its excellent conductivity (3.10 × 103 Ω), the fabricated composite coating had good durability and wear resistance. After 10 sand-washing cycles, the CSC coating surface still exhibited stable superhydrophobicity (149° WCA, 9.5° SA). At 200 g pressure, the surface of the optimized CSC coating still maintained fine superhydrophobicity (150° WCA, 9.2° SA) and conductivity (1.86 × 104 Ω) after 10 abrasion cycles. In addition, it also exhibited fine adhesion (0.307 MPa) between the composite coating and the substrate. This functional superhydrophobic surface can be applied in specialty fields with harsh conditions such as coal mining and petrochemical activities. This new coating may also expand the application fields of superhydrophobic surfaces and have broad practical application prospects.

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 A simple fabrication of superhydrophobic PVDF/SiO2 coatings and their anti-icing properties

2021 ◽  
Author(s):  
Xinyu Tan ◽  
Zhengtao Huang ◽  
Lihua Jiang ◽  
Ting Xiao ◽  
Yunkuan Wang ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Low Cost ◽  
Dip Coating ◽  
Large Temperature ◽  
Sliding Angle ◽  
Water Contact ◽  
Superhydrophobic Coatings ◽  
Coating Method ◽  
Large Water ◽  
Dip Coating Method

AbstractSuperhydrophobic coatings have been regarded as potential promising solutions to many problems, e.g., ice accumulation in the winter seasons. To be practically useful and economically attractive, it is necessary to fabricate such coatings using facile methods, i.e., with minimal steps and low cost. In this work, a polyvinylidene fluoride (PVDF)/SiO2 coating is successfully prepared with a simple dip coating method. It shows impressive superhydrophobic properties with a large water contact angle (WCA) of 159° and a small sliding angle (SA) of less than 3°. Meanwhile, its superhydrophobic properties are robust in a large temperature range of – 30 to 350 °C and in various environments. Moreover, it shows remarkable anti-icing properties by delaying the freezing time (4 times) and reducing (40%) the adhesion of the ice on the substrate. Therefore, this work has displayed a promising approach for fabricating superhydrophobic coatings towards anti-icing applications.

scholarly journals Hybrid Sol–Gel Superhydrophobic Coatings Based on Alkyl Silane-Modified Nanosilica

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 539
Author(s):  
Dafna Heiman-Burstein ◽  
Anna Dotan ◽  
Hanna Dodiuk ◽  
Samuel Kenig
Keyword(s):  
Contact Angle ◽  
Sol Gel ◽  
Alkyl Substituent ◽  
Hybrid Coatings ◽  
Sliding Angle ◽  
Random Surface ◽  
Water Contact ◽  
Superhydrophobic Coatings ◽  
Long Chain

Hybrid sol–gel superhydrophobic coatings based on alkyl silane-modified nanosilica were synthesized and studied. The hybrid coatings were synthesized using the classic Stöber process for producing hydrophilic silica nanoparticles (NPs) modified by the in-situ addition of long-chain alkyl silanes co-precursors in addition to the common tetraethyl orthosilicate (TEOS). It was demonstrated that the long-chain alkyl substituent silane induced a steric hindrance effect, slowing the alkylsilane self-condensation and allowing for the condensation of the TEOS to produce the silica NPs. Hence, following the formation of the silica NPs the alkylsilane reacted with the silica’s hydroxyls to yield hybrid alkyl-modified silica NPs having superhydrophobic (SH) attributes. The resulting SH coatings were characterized by contact angle goniometry, demonstrating a more than 150° water contact angle, a water sliding angle of less than 5°, and a transmittance of more than 90%. Confocal microscopy was used to analyze the micro random surface morphology of the SH surface and to indicate the parameters related to superhydrophobicity. It was found that a SH coating could be obtained when the alkyl length exceeded ten carbons, exhibiting a raspberry-like hierarchical morphology.

scholarly journals An advancement in the synthesis of unique soft magnetic CoCuFeNiZn high entropy alloy thin films

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chokkakula L. P. Pavithra ◽  
Reddy Kunda Siri Kiran Janardhana ◽  
Kolan Madhav Reddy ◽  
Chandrasekhar Murapaka ◽  
Joydip Joardar ◽  
...  
Keyword(s):  
Thin Films ◽  
Saturation Magnetization ◽  
Functional Materials ◽  
Single Step ◽  
High Entropy Alloy ◽  
High Saturation Magnetization ◽  
Soft Magnetic ◽  
High Entropy ◽  
High Saturation ◽  
Electrochemical Approach

AbstractDiscovery of advanced soft-magnetic high entropy alloy (HEA) thin films are highly pursued to obtain unidentified functional materials. The figure of merit in current nanocrystalline HEA thin films relies in integration of a simple single-step electrochemical approach with a complex HEA system containing multiple elements with dissimilar crystal structures and large variation of melting points. A new family of Cobalt–Copper–Iron–Nickel–Zinc (Co–Cu–Fe–Ni–Zn) HEA thin films are prepared through pulse electrodeposition in aqueous medium, hosts nanocrystalline features in the range of ~ 5–20 nm having FCC and BCC dual phases. The fabricated Co–Cu–Fe–Ni–Zn HEA thin films exhibited high saturation magnetization value of ~ 82 emu/g, relatively low coercivity value of 19.5 Oe and remanent magnetization of 1.17%. Irrespective of the alloying of diamagnetic Zn and Cu with ferromagnetic Fe, Co, Ni elements, the HEA thin film has resulted in relatively high saturation magnetization which can provide useful insights for its potential unexplored applications.

scholarly journals Unconventional Materials Processing Using Spark Plasma Sintering

Ceramics ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 20-40
Author(s):  
Ambreen Nisar ◽  
Cheng Zhang ◽  
Benjamin Boesl ◽  
Arvind Agarwal
Keyword(s):  
Spark Plasma Sintering ◽  
Real Life ◽  
Functional Materials ◽  
Research Field ◽  
Advanced Materials ◽  
Plasma Sintering ◽  
Challenges And Opportunities ◽  
Future Challenges ◽  
Gas Quenching ◽  
Spark Plasma

Spark plasma sintering (SPS) has gained recognition in the last 20 years for its rapid densification of hard-to-sinter conventional and advanced materials, including metals, ceramics, polymers, and composites. Herein, we describe the unconventional usages of the SPS technique developed in the field. The potential of various new modifications in the SPS technique, from pressureless to the integration of a novel gas quenching system to extrusion, has led to SPS’ evolution into a completely new manufacturing tool. The SPS technique’s modifications have broadened its usability from merely a densification tool to the fabrication of complex-shaped components, advanced functional materials, functionally gradient materials, interconnected materials, and porous filter materials for real-life applications. The broader application achieved by modification of the SPS technique can provide an alternative to conventional powder metallurgy methods as a scalable manufacturing process. The future challenges and opportunities in this emerging research field have also been identified and presented.

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