Effects of Air Exposure Time and Annealing Temperature on Superhydrophobic Surface of Titanium Dioxide Films

2017 ◽  
Vol 751 ◽  
pp. 137-142
Author(s):  
S.Tipawan Khlayboonme ◽  
Warawoot Thowladda
Keyword(s):  
Contact Angle ◽  
Surface Morphology ◽  
Exposure Time ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Contact Angles ◽  
Angle Measurement ◽  
Elemental Distribution ◽  
Water Contact ◽  
Air Exposure

TiO2 thin films coated on glass substrates for self-cleaning applications were prepared by sol-gel dip-coating technique. The influence of annealing temperature and air exposure time on wettability was investigated by a water contact-angle measurement. Thermal annealing at temperatures of 100, 200 and 300 °C in air were conducted to the films. Surface morphology of the films was observed by FE-SEM. Elemental distribution and optical properties were examined by EDX mapping and UV-Vis transmission spectroscopy, respectively. Atomic bonding was confirmed by FTIR. The contact angle reached a maximum when the films were annealed at 200 °C. The contact angles of the as-synthesized films were 61.4±2.7°. During storage in air for 20 days, the contact angles increased to 143.1±2.1°. The films were further reannealed with 100 °C for 20 min, the contact angles were enhanced to 153.1±1.3°. The association of contact angle among the surface morphology, elemental distribution and atomic bonding of the films will be discussed.

Preparation of TiO2–SiO2 Hybrid Nanosols Coated Flame-Retardant Polyester Fabric Possessing Dual Contradictory Characteristics of Superhydrophobicity and Self Cleaning Ability

2020 ◽  
Vol 20 (3) ◽  
pp. 1780-1789 ◽  
Author(s):  
Priyanka Katiyar ◽  
Shraddha Mishra ◽  
Anurag Srivastava ◽  
N. Eswara Prasad
Keyword(s):  
Electron Microscopy ◽  
Contact Angle ◽  
Flame Retardant ◽  
Protective Clothing ◽  
Sol Gel ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Water Contact ◽  
Vis Spectroscopy ◽  
Self Cleaning

TiO2, SiO2 and their hybrid nanocoatings are prepared on inherent flame retardant textile substrates from titanium(IV)iso-proproxide (TTIP) and tetraethoxysilane (TEOS) precursors using a sol–gel process followed by hydrothermal treatment. The coated samples are further functionalized by hexadecyltrimethoxysilane (HDTMS) to impart superhydrophobicity. Sample characterization of the nanosols, nanoparticles and coated samples are investigated using, X-ray diffractometer, transmission electron microscopy, scanning electron microscopy, UV-Vis spectroscopy, contact angle measurement. Stain degradation test under mild UV irradiation shows almost 54% degradation of coffee stain within 4 hours measured by Spectrophotometer. UV-Vis Absorption Spectroscopy demonstrates complete degradation of methyl orange colorant within 3 hours. Hybrid nanosol coated and HDTMS modified inherent flame retardant polyester surfaces show apparent water contact angle as ~145°, which is much closer to proximity of superhydrophobic surfaces. Thus, the novelty of present work is, by using sol–gel technique, a bi-functional textile surface has been developed which qualifies the very specific requirements of protective clothing like self-cleaning property (imparted by TiO2 nanoparticles) and superhydrophobicity (imparted by SiO2 nanoparticles and further surface modification by HDTMS), which are entirely contradictory in nature, in a single fabric itself. Thus developed textile surfaces also possess the other attributes of protective clothing like flame retardancy and air permeability.

Preparation of TiO2 Thin Films and its Superhydrophilic Properties

2009 ◽  
Vol 620-622 ◽  
pp. 695-698
Author(s):  
Jing Ma ◽  
Wen Xiu Liu ◽  
Xiao Guang Qu ◽  
Dan Ni Yu ◽  
Wen Bin Cao
Keyword(s):  
Thin Film ◽  
Tio2 Thin Film ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Soda Lime ◽  
Contact Angles ◽  
Soda Lime Glass ◽  
Water Contact ◽  
Different Temperatures ◽  
Hydrolysis Of

TiO2 thin film was prepared on soda lime glass by hydrolysis of Ti(OC4H9)4 in alcoholic solutions by sol-gel method combined with spin-coating and calcination different temperatures. Prepared samples were characterized by XRD, FESEM, and measurement of contact angles and transmittance. XRD identification reveals that the films are composed of anatase TiO2 when the annealing temperature was set at 450~550 oC. SiO2 layer was coated on the surface of the glass firstly to barrier the diffusing of sodium ions from the substrate. Light-induced superhydrophilicity of the TiO2 thin film has been investigated. To increase the illumination light intensity will decrease the water contact angle. The superhydrophilicity of the TiO2 thin film will disappear more slowly in the dark than that in the field of ultrasound.

Multifunctional nanocomposite transparent UV-blocking films sythesized by sol-gel process for optical, automotive and aeronautic applications

2005 ◽  
Vol 901 ◽  
Author(s):  
Phani Ratna Ayalasomayajula ◽  
S. Santucci
Keyword(s):  
Thin Films ◽  
Contact Angle ◽  
Morphological Changes ◽  
Sol Gel ◽  
Chemical Properties ◽  
Contact Angles ◽  
Nanocomposite Films ◽  
Energy Materials ◽  
Water Contact ◽  
Uv Blocking

AbstractDevelopment of UV blocking thin films with effective cut-off features with steep edges and high transmission in the visible and IR region have been developed. The unique optical, mechanical and chemical properties of silica and ceria nanocomposites with surface functional groups making them most promising candidate for applications in opto-electronic, automotive, and aeronautic industries. On the other hand, highly hydro and oleophobic films are being actively considered in optical, automotive and aeronautic industries to increase adhesion and scratch, abrasion resistance properties. In order to fill the gap, and fulfill the requirements to meet both ends, it could be proved that morphological changes in the nanometer range influences the water contact angles and their hystersis of low energy materials. Nanocomposite films of SiO2 and CeO2 with surface functionalisation with decafluorooctly-triethoxy silane itself forms nano-hemispheres (similar to lotus leaf) at and above 100°C favoring an increase in water contact angle from 122° (25°C) to 145°(400°C). The structural, optical, and hydrophobic properties have been examined by employing X-ray diffraction, UV-visible spectroscopy, contact angle techniques, respectively. The cut-off behavior of the deposited and annealed nanocomposite thin films have been tuned by varying different amounts of CeO2 in SiO2.

Hydrophobicity Enhancement of the Polyvinyl Alcohol/Rice Starch/Silk Fibroin Films by Glycerol

2013 ◽  
Vol 446-447 ◽  
pp. 360-365
Author(s):  
Pusita Kuchaiyaphum ◽  
Takeshi Yamauchi ◽  
Ruangsri Watanesk ◽  
Surasak Watanesk
Keyword(s):  
Contact Angle ◽  
Polyvinyl Alcohol ◽  
Silk Fibroin ◽  
Water Solubility ◽  
Contact Angle Measurement ◽  
Contact Angles ◽  
Angle Measurement ◽  
Rice Starch ◽  
Water Contact ◽  
Degree Of Swelling

Eco-friendly films have been prepared using various biopolymers and their properties have been improved in order to meet the requirements for appropriate applications. However, the frequently encountered weakness of the properties of most biopolymer film is its water solubility. In this study, the polyvinyl alcohol/rice starch/silk fibroin (PVA/RS/SF) films were modified by the addition of glycerol aiming to increase the hydrophobicity of the films. Some properties of the modified films including water contact angle, degree of swelling and water solubility were compared with the unmodified PVA/RS/SF film. Results from the contact angle measurement showed that the films with glycerol could be transformed to be hydrophobic after soaking in ethanol medium. The increase in soaking time tends to increase the hydrophobicity of the films. However, at about 60 min soaking, the water contact angles on the films were quite constant with the values of about 107.9±5.2º comparing with 65.3±2.4º of the ethanol-untreated PVA/RS/SF films. In addition, the ethanol-treated glycerol-modified films also show higher degree of swelling with constant solubility and better mechanical properties.

Optical Transparent and Hydrophobic Properties of TEOS/OTES Hybrid Materials by Sol-Gel Processing

2019 ◽  
Vol 798 ◽  
pp. 134-139
Author(s):  
Usanee Pantulap ◽  
Benjamon Petchareanmongkol ◽  
Waraporn Kaewdang ◽  
Kanit Tapasa
Keyword(s):  
Contact Angle ◽  
Sol Gel ◽  
Contact Angles ◽  
Light Transmittance ◽  
Film Properties ◽  
Water Contact ◽  
Atomic Force ◽  
Commercial Glass ◽  
Gel Processing ◽  
Hydrolysis Of

The objective of this project was to develop the hydrophobic film for self-cleaning glasses. The effects of octyltriethoxysilane (OTES) additions to hydrolysis of tetraethylorthosilicate (TEOS) on hydrophobic and optically transparent properties were studied. The film was prepared by sol-gel method from the precursors namely, TESO, OTES, isopropanol alcohol (IPA), and deionized water (DI). The sols for coating were obtained with TEOS/OTES ratio of 50:50 to 99:1. The sols were deposited on a commercial glass and dried at 60oC for an hour. After drying, the film properties were characterized by fourier transform infrared spectroscopy (FTIR), UV-VIS Spectrophotometer, x-Ray Diffractometer (XRD), atomic force microscope (AFM), optical microscopy and contact angle meter. It was found that contact angles of the hybrid films increased with the OTES addition, reaching a maximum at 10 wt.%, and the contact angle values were the same as for further addition. The light transmittance was rather stable with increasing amounts of OTES. For the optimized condition, the water contact angle of 108o and light transmittance of 91%, was obtained with TEOS/OTES ratio of 90:10.

Preparation and Properties of TiO2 Thin Films Deposited on Different Substrates by Sol-Gel Method

2014 ◽  
Vol 979 ◽  
pp. 355-358 ◽  
Author(s):  
Tanattha Rattana ◽  
Nirun Witit-Anun ◽  
Sumetha Suwanboon ◽  
Surasing Chaiyakun
Keyword(s):  
Thin Films ◽  
Contact Angle ◽  
Stainless Steel ◽  
Silicon Wafer ◽  
Irradiation Time ◽  
Sol Gel ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Ambient Atmosphere ◽  
Water Contact

In this work, TiO2thin films were prepared by a sol-gel spin coating method on glass slide, stainless steel 304 and silicon wafer substrates. The thin films were annealed at different temperatures at ambient atmosphere. The effect of substrates and annealing temperatures on microstructure, surface morphology and hydrophilicity of the films were characterized by Raman spectroscopy, atomic force microscopy and water contact angle measurement, respectively. The Raman spectra indicated that the annealed TiO2thin films (at 550 °C) coated on stainless steel and silicon wafer exhibited anatase structure. The contact angle of all samples decreased with increasing the UV-irradiation time and annealing temperature.

Contact Angle Measurement and Its Application To Sol-Gel Processing

1994 ◽  
Vol 346 ◽  
Author(s):  
D. J. Stein ◽  
A. Maskara ◽  
S. Hæreid ◽  
J. Anderson ◽  
D. M. Smith
Keyword(s):  
Contact Angle ◽  
Sol Gel ◽  
Dynamic Contact ◽  
Dip Coating ◽  
Contact Angles ◽  
Angle Measurement ◽  
Silica Gels ◽  
Solid Matrix ◽  
Surface Tensions ◽  
Gel Processing

ABSTRACTCapillary stresses during drying that result from the contact angle of a liquid solvent to a gel, surface tension, and pore size have an immense effect on the dried gel. The extent to which the gel shrinks is a balance between the capillary stress and the solid matrix strength. The dynamic contact angles and surface tensions of various solvents commonly employed in sol-gel processing on silica gels of various surface chemistries have been evaluated. A thin, dense coating of silica gel was formed by dip coating a standard glass slide in an acid catalyzed silica sol and drying. Some of the sample surfaces were organically modified. Dynamic contact angles were determined using a modified Wilhelmy plate technique. Solvent surface tensions were determined using the De Nouy ring technique. The bulk modulus of wet gels were determined with a three point bend experiment. We have found that contrary to previous investigators, who attributed different bulk densities obtained after drying from various alcohols to contact angles variations, gel shrinkage during drying is actually due to slightly different surface tensions and degrees of depolymerization of the gel network.

scholarly journals Assessment of Super-Hydrophobic Textured Coatings on AA6082 Aluminum Alloy

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 352 ◽  
Author(s):  
Luigi Calabrese ◽  
Amani Khaskhoussi ◽  
Salvatore Patane ◽  
Edoardo Proverbio
Keyword(s):  
Contact Angle ◽  
Surface Morphology ◽  
In Situ Polymerization ◽  
Contact Angles ◽  
Measuring System ◽  
Hydrophobic Surfaces ◽  
Short Term Treatment ◽  
Water Contact ◽  
Water Separation ◽  
Wide Range

Superhydrophobicity is one of the most required surface properties for a wide range of application such as self-cleaning, anti-corrosion, oil-water separation, anti-icing, and anti-bioadhesion. Recently, several methods have been developed to produce nature inspired super-hydrophobic surfaces. Nevertheless, these methods require a complicated process and expensive equipment. In order to overcome these issues, we propose three different methods to obtain nature-inspired super-hydrophobic surfaces: short-term treatment with boiling water, HF/HCl and HNO3/HCl concentrated solution etching. Afterwards, a thin layer of octadecylsilane was applied by in situ polymerization on all pre-treated surfaces. Eventually, all substrates were dried for 3 h at 100 °C to complete the silane curing. Scanning electron microscopy (SEM), contact angle measuring system and atomic force microscope (AFM) were used to characterize the surfaces. Surface morphology analysis showed that each method results in a specific dual hierarchical nano-/micro-structure. The corresponding water contact angles ranged from 160° to nearly 180°. The best results were observed for HF etched Al 6082 surface were water contact angle above 175° was achieved. Furthermore, a scheme able to assess the relationship between hydrophobic behavior and surface morphology was finally proposed.

Effects of Surface Treatments of Polycaprolactone Scaffolds on their Properties

2013 ◽  
Vol 747 ◽  
pp. 178-181 ◽  
Author(s):  
Wasana Kosorn ◽  
Boonlom Thavornyutikarn ◽  
Wanida Janvikul
Keyword(s):  
Contact Angle ◽  
Plasma Treatment ◽  
Alkaline Hydrolysis ◽  
Photoelectron Spectroscopy ◽  
Atomic Ratio ◽  
Contact Angle Measurement ◽  
Contact Angles ◽  
Angle Measurement ◽  
Water Contact ◽  
Oh Groups

Polycaprolactone (PCL) was surface modified with alkaline hydrolysis by NaOH and/or low pressure oxygen (O2) plasma treatment. The hydrolysis was conducted in two different stages: one was performed prior to PCL scaffold fabrication by a high pressure supercritical CO2 technique; the other was carried out after the fabrication. The resulting hydrolyzed PCL scaffolds, with pore sizes in the range of 150-250 μm, were denoted as pre-HPCL and post-HPCL, respectively. Both non-hydrolyzed and hydrolyzed PCL scaffolds were subsequently subjected to the plasma treatment, to further enhance the hydrophilicity of the scaffolds. The surface morphology, wettability and chemical composition of all PCL scaffolds were analyzed by scanning electron microscopy (SEM), water contact angle measurement, and X-ray photoelectron spectroscopy (XPS), respectively. It was found that the surface of the scaffolds turned from fairly smooth to highly rough after the hydrolysis and plasma treatment, particularly when both treatments were in use. The post-hydrolysis induced more surface roughness, compared to the pre-hydrolysis. In addition, the water contact angles on the scaffolds enormously reduced after the treatments; plasma treatment, however, showed a more prominent effect than the alkaline hydrolysis. Although expressing a zero-degree contact angle, the plasma-treated pre-HPCL scaffold was wetted more readily than the plasma-treated post-HPCL. These were in good agreement with the XPS results; interestingly, the plasma-treated pre-HPCL scaffold exhibited the greatest O/C atomic ratio among the PCL scaffolds. This indicated its highest extent of PCL chain oxidation, a degradation of ester groups into-COOH and-OH groups.

scholarly journals The role of contact angle and pore width on pore condensation and freezing

2020 ◽  
Vol 20 (15) ◽  
pp. 9419-9440 ◽  
Author(s):  
Robert O. David ◽  
Jonas Fahrni ◽  
Claudia Marcolli ◽  
Fabian Mahrt ◽  
Dominik Brühwiler ◽  
...  
Keyword(s):  
Contact Angle ◽  
Active Sites ◽  
Water Saturation ◽  
Sol Gel ◽  
Contact Angles ◽  
Ice Nucleation ◽  
Pore Width ◽  
Water Contact ◽  
Pore Condensation

Abstract. It has recently been shown that pore condensation and freezing (PCF) is a mechanism responsible for ice formation under cirrus cloud conditions. PCF is defined as the condensation of liquid water in narrow capillaries below water saturation due to the inverse Kelvin effect, followed by either heterogeneous or homogeneous nucleation depending on the temperature regime and presence of an ice-nucleating active site. By using sol–gel synthesized silica with well-defined pore diameters, morphology and distinct chemical surface-functionalization, the role of the water–silica contact angle and pore width on PCF is investigated. We find that for the pore diameters (2.2–9.2 nm) and water contact angles (15–78∘) covered in this study, our results reveal that the water contact angle plays an important role in predicting the humidity required for pore filling, while the pore diameter determines the ability of pore water to freeze. For T>235 K and below water saturation, pore diameters and water contact angles were not able to predict the freezing ability of the particles, suggesting an absence of active sites; thus ice nucleation did not proceed via a PCF mechanism. Rather, the ice-nucleating ability of the particles depended solely on chemical functionalization. Therefore, parameterizations for the ice-nucleating abilities of particles in cirrus conditions should differ from parameterizations at mixed-phase clouds conditions. Our results support PCF as the atmospherically relevant ice nucleation mechanism below water saturation when porous surfaces are encountered in the troposphere.

Sign in / Sign up

Export Citation Format

Share Document