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.

Study on self-cleaning performance and hydrophobicity of TiO2/silane coatings

2018 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
A. Syafiq ◽  
A.K. Pandey ◽  
Vengadaesvaran Balakrishnan ◽  
Nasrudin Abd Rahim
Keyword(s):  
Glass Substrate ◽  
Substrate Surface ◽  
Phase Interface ◽  
Dip Coating ◽  
Vacuum Furnace ◽  
Coating Film ◽  
Sliding Angle ◽  
Water Contact ◽  
Content Type ◽  
Self Cleaning

PurposeThe paper aims to investigate the effect of Degussa P-25 Titanium Dioxide (TiO2) nanoparticles on hydrophobicity and self-cleaning ability as a single organic coating on glass substrate.Design/methodology/approachTwo methods have been used to enhance the hydrophobicity on glass substrates, namely, surface modification by using low surface energy isooctyltrimethoxysilane (ITMS) solution and construction of rough surface morphology using Degussa P-25 TiO2nanoparticles with simple bottom-up approach. The prepared sol was applied onto glass substrate using dip-coating technique and stoved in the vacuum furnace 350°C.FindingsThe ITMS coating with nano TiO2pigment has modified the glass substrate surface by achieving the water contact angle as high as 169° ± 2° and low sliding angle of 0° with simple and low-cost operation. The solid and air phase interface has created excellent anti-dirt and self-cleaning properties against dilute ketchup solution, mud and silicon powder.Research limitations/implicationsFindings will be useful in the development of self-cleaning and anti-dirt coating for photovoltaic panels.Practical implicationsSol method provides the suitable medium for the combination of organic–inorganic network to achieve high superhydrophobicity and optimum self-cleaning ability.Originality/valueApplication of blended organic–inorganic sol as self-cleaning and anti-dirt coating film.

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 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.

Room Temperature Processed Hard Easy Clean Coating Using Ammonia Treatment

2010 ◽  
Vol 447-448 ◽  
pp. 740-744 ◽  
Author(s):  
Xiao Zhang ◽  
Min Qian ◽  
Yu Chan Liu ◽  
Hong Xie
Keyword(s):  
Room Temperature ◽  
Water Drop ◽  
Sol Gel ◽  
High Hardness ◽  
Hard Coatings ◽  
Sliding Angle ◽  
Water Contact ◽  
Pencil Hardness ◽  
Glass Substrates ◽  
Plastic Surface

In this paper we report the fabrication of hydrophobic hard coatings using sol-gel processing and cured at room temperature by an ammonia-assisted process. The coating thickness can be tuned from several hundreds of nanometer to several microns. These coatings show both high transparency (better than PMMA or glass substrates) and high hardness (pencil hardness 2H-4H on PMMA). The coatings are very smooth with surface roughness Ra less than 2 nm for coatings with different thicknesses from 200 nm to 2 m. The water contact angle (WCA) of the coating is about 115 to 120o and the sliding angle for a 20 l water drop is less than 10o. The advantage of this process is the ease for larger area application and especially suitable for plastic surface treatment due to the low temperature curing process.

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.

Preparation and pore structure stability at high temperature of silicon-doped ordered mesoporous alumina

RSC Advances ◽  
2014 ◽  
Vol 4 (24) ◽  
pp. 12497-12505 ◽  
Author(s):  
Xiaoliang Zhao ◽  
Ying Zheng ◽  
Yong Zheng ◽  
Yingying Zhan ◽  
Xuelin Zheng
Keyword(s):  
Thermal Stability ◽  
Silicon Content ◽  
Sol Gel ◽  
High Thermal Stability ◽  
Mesoporous Alumina ◽  
Structure Stability ◽  
Residual Chlorine ◽  
Ordered Mesoporous ◽  
Ordered Mesoporous Alumina ◽  
Silicon Doped

Ordered mesoporous γ-Al2O3 with high thermal stability and low-level residual chlorine is obtained by optimizing sol–gel parameters and silicon content.

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.

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