Water-repellent glass coated with SiO2–TiO2–methyltrimethoxysilane through sol–gel coating (original) (raw)
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Water-repellent glass coated with SiO2–TiO2–methyltrimethoxysilane through sol–gel coating
AIMS Materials Science, 2019
A hydrophobic coating for glass substrates was developed using SiO 2 , TiO 2 , and methyltrimethoxysilane (MTMS) to achieve low surface energy and a rough surface. The coating process was conducted using a sol-gel method and layer by layer deposition. The effect of SiO 2 , TiO 2 , and MTMS on the hydrophobicity and transparency of the coating were evaluated using contact angle and optical transmittance measurements, respectively. The transparency was found to decrease with higher moles of SiO 2 , TiO 2 , and MTMS; the water contact angle initially increased with increasing addition of these reagents, but then declined above the optimum conditions. The optimum conditions were determined to be at approximately 0.075, 0.030, and 0.002 mol of SiO 2 , TiO 2 , and MTMS, respectively. The resulting water contact angle was 115.56 ± 1.01°. SiO 2 and TiO 2 provided a synergistic effect to improve the roughness surface, as shown in the AFM data. The glass coated using SiO 2-TiO 2-MTMS exhibited higher hardness values than bare glass.
Open Chemistry
This research work presents the design of a mixture of SiO2/TiO2 that increases the surface roughness and hydrophobicity of methyltrimethoxysilane (MTMS) coated glass. The deposition of SiO2, TiO2, and MTMS were conducted using a layer by layer dip coating technique. The SiO2/TiO2 coating was derived from complete hydrolysis of tetraethylorthsilicate and titanium tetraisopropoxide. In order to evaluate and compare the performance of SiO2/TiO2/MTMS coated glass, the SiO2/SiO2/MTMS and TiO2/TiO2/MTMS were also fabricated. SiO2/TiO2/MTMS samples displayed the highest water contact angle. The topography of surfaces showed that SiO2/TiO2/MTMS exposed higher surface roughness with micro-nanoscale structures. The sequence of SiO2 and TiO2 influenced the water contact angle and the stability of the coatings. SiO2/TiO2/MTMS produced higher contact angle and stability than TiO2/SiO2/MTMS.
Silica-Methyltrimethoxysilane Based Hydrophobic Coatings on a Glass Substrate
2017
The preparation of silica-methyltrimethoxysilane nanocomposites and their effect on the glass surface wettability performance were investigated. TEOS, sodium silicate, and rice husk ash were the silica sources used. In this research, rice husk ash was converted into sodium silicate through a reaction with amorphous silica and NaOH. The optimum silica concentration providing the highest hydrophobicity was determined. The silica nanoparticles were characterized by XRD, the hydrophobicity was measured by the water contact angle (WCA) test, the surface roughness was analyzed by AFM, while the transparency was determined spectrophotometrically. The different silica source used affected the hydrophobicity of the coated glass. The nanocomposite using TEOS as a silica source showed the highest WCA (132°), whereas sodium silicate and rice husk ash showed similar WCA (around 116°). Furthermore, WCA was also found affected by the amount of silica. WCA increases with silica amount increase.
Porous water repellent silica coatings on glass by sol–gel method
Development of the solid surfaces with waterrepellent and self-cleaning ability has attracted much research interest in recent years. In the present research work, we have prepared water repellent silica coatings on glass at room temperature (*27 C) by sol gel process and surface silylation technique. Coating sol was prepared by keeping the molar ratio of tetramethoxysilane (TMOS), methanol (MeOH) and water (H2O) constant at 1:12.36:4.25, respectively, with 0.01 M NH4F. The dip coated silica films were surface silylated using two different silylating agents namely hexamethyldisiloxane (HMDSO) and hexamethyldisilazane (HMDZ). The HMDSO and HMDZ in hexane solvent were varied from 0 to 1 vol.% and silylation period was varied from 1 to 3 h. The HMDSO and HMDZ modified films showed dense and porous surface morphology, respectively. The HMDSO modified silica films showed static water contact angle of 122 whereas HMDZ modified films showed 165. The HMDZ modified films displayed the extreme water repellency comparing with that of lotus leaves. The silica films were characterized by surface profilometer, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared microscopy, thermal and chemical aging tests, optical transmission and static water contact angle measurements.
Sol–gel preparation of PTMS modified hydrophobic and transparent silica coatings
Journal of Porous Materials, 2013
Wettability of solid surfaces is an important property, which depends on both the surface chemistry and surface roughness. The present paper describes the room temperature synthesis of dip coated water repellent silica coatings on glass substrates using phenyltrimethoxysilane (PTMS) as a co-precursor with two-step sol-gel process. Silica sol was prepared by keeping the molar ratio of tetraethylorthosilicate precursor, methanol solvent, acidic water (0.001 M oxalic acid) and basic water (12 M NH 4 OH) constant at 1:11.03:0.17:0.58 respectively, throughout the experiments and the PTMS weight percentage was varied from 0 to 15 %. It was found that with an increase in wt% of PTMS, the roughness and hydrophobicity of the films increased. However, the optical transmission decreased from 93 to 82 % in the visible range. The hydrophobic silica films retained their hydrophobicity up to a temperature of 386°C and above this temperature the films became hydrophilic. The hydrophobic silica thin films were characterized by taking into consideration the surface roughness studies, Fourier transform infrared spectroscopy, percentage of optical transmission, scanning electron microscopy, thermogravimetric-differential thermal analysis and contact angle measurements.
OTES modified transparent dip coated silica coatings
Ceramics International, 2013
The present paper describes the room temperature synthesis of dip coated water repellent silica coatings on glass substrates using octyltriethoxysilane (OTES) as a co-precursor with two-step sol-gel process. Silica sol was prepared by keeping the molar ratio of tetraethylortosilicate (TEOS) precursor, methanol (MeOH) solvent, acidic water (0.001 M oxalic acid) and basic water (12 M NH 4 OH) constant at 1:11.03:0.17:0.58 respectively, throughout the experiments and the OTES weight percentage was varied from 0% to 15%. It was found that with an increase in wt% of OTES, the roughness and hydrophobicity of the films increased, however the optical transmission decreased from 93% to 88% in the visible range. The hydrophobic silica films retained their hydrophobicity up to a temperature of 259 1C and above this temperature, the films became hydrophilic. The hydrophobic silica thin films were characterized by taking into consideration the surface roughness studies, Fourier transform infrared (FT-IR) spectroscopy, percentage of optical transmission, scanning electron microscopy (SEM), Thermogravimetric-differential thermal analysis (TG-DTA) and contact angle measurements.
Hydrophobic and oleophobic sol-gel coatings on glass substrates for usage at high temperatures
International Journal of Applied Glass Science, 2018
The paper reports an optimized process to obtain transparent and highly hydrophobic sol-gel coatings with further oleophobic behavior at high temperatures. Polyorganosiloxane sols were prepared incorporating an organic based precursor, 1H,1H,2H,2H Perfluorooctyltriethoxysilane (POTS), into a silica-based hybrid sol and deposited on soda-lime glass-slides. The coating surfaces show high water contact angle (WCA) around 120 AE 1°and oil contact angle (OCA) of 70 AE 1°after curing at temperatures between 350 and 400°C. The coatings thickness changed between 300 and 2000 nm depending on sol composition and curing temperature. Easy-to-clean tests were performed, the results showing excellent anti-stick and easy-to-clean properties compared to non-coated samples. Atomic force microscopy (AFM) revealed the presence of rippled surfaces with morphology similar to "lotus leaf surface," this explaining the properties. These hybrid fluoroalkylsilane sol-gel coatings are a good alternative to provide antistick and easy-to-clean properties to glass substrates being quite easy to scale up.
Surface and Coatings Technology, 2012
This paper reports the synthesis of hydrophobic and antireflective coatings by sol-gel process at room temperature (25°C), using tetraethylorthosilicate (TEOS) as a precursor and methyltriethoxysilane (MTES), phenyltriethoxysilane (PTES), vinyltriethoxysilane (VTES), and octyltriethoxysilane (OTES) as surface modifying agents. The silica sol was prepared by keeping the molar ratio of TEOS:RTES at 1:1, in acidic conditions with ethanol and 0.1 M HCl. All hybrid systems were enriched with titanium(IV) isopropoxide as the cross-linking agent. It was observed that the obtained silica films become hydrophobic with the introduction of the hydrophobic organic group. The higher value of static water contact angle (107 ± 3°) was obtained for the silica film prepared with TEOS + OTES. Under optimal synthesis condition, we obtained antireflection coatings, exhibiting a low reflection in the visible range.
Tribology of water and oil repellent sol–gel coatings for optical applications
Wear, 2009
Oil and water repellent sol-gel silica coatings may be used to extend the use and lifetime of certain computer displays, optoelectronic devices, and optical components such as touch screens. Organic-inorganic coatings consisting of organically modified silica are an optimal class of materials to use for such applications as they are substantially more durable than conventional polymers while having low processing temperatures compatible with organics. This study is concerned with the characterization of wear-resistant coatings derived from polysiloxanes. Organically modified sol-gel silica coatings were deposited on soda-lime glass substrates by dip coating. Mechanical, surface, and tribological properties were investigated using nanoindentation, contact angle goniometry, stylus profilometry, and a reciprocating polishing wear test to determine wear rate by mass loss. The average hardness of films was found to be 1.2 GPa and independent of curing times above 30 min at 150 • C. In polishing wear, failure was caused by gradual abrasive wear through the depth of the coating. Wear rate was found to be independent of curing times above 30 min at 150 • C. The development of these coatings will contribute to the rational design of the next generation of transparent overlays and displays.
Journal of Sol-Gel Science and Technology, 2012
A simple fabrication method towards a novel morphology followed by hydrophobic and pencil scratch resistant film based on silica nanoparticles was successfully achieved from methyltrimethoxysilane on glass by spin coating technique. The polyvinyl alcohol was employed for grafting the microporous network of the silica nanoparticles. The enrichment in hydrophobicity and pencil scratch resistance properties of the silica nanoparticles was achieved by adapting a polymer route. Since, the silica particles are in the nanometer size the films are excellent in transmission of light in the visible region. The water drop contact angle was high, up to *169 ± 1°, for 10 lL volume of water and the sliding angle was achieved minimum to 5 ± 1°. Non-wetting property was tested by keeping the film in the humidity chamber for over 60 days. The silica film demonstrated resistance to scratches by a pencil of 4 H grade as per the ASTM D 3363 method. The feasible potential approach towards the fabrication of the superhydrophobic silica film with tailored nanoporous network and scratch resistant assets is indispensable for many practical applications.