Correlation of Superhydrophilicity and Photocatalytic Activity in the TiO2-Based Porous Thin Films

2006 ◽  
Vol 510-511 ◽  
pp. 54-57 ◽  
Author(s):  
Seung Yong Chai ◽  
Jin Koo Park ◽  
Ho Kun Kim ◽  
Wan In Lee
Keyword(s):  
Contact Angle ◽  
Photocatalytic Activity ◽  
Uv Irradiation ◽  
Uv Light ◽  
Irradiation Time ◽  
Colloidal Suspension ◽  
Initial Point ◽  
Film Surface ◽  
Contact Angles ◽  
Tio2 Films

Transparent TiO2, WO3-TiO2, and MoO3-TiO2 films were prepared by spin-coating each colloidal suspension. The monolayer coverage of WO3 on the surface of TiO2 greatly increased the photocatalytic activity in the decomposition of gaseous 2-propanol, whereas the addition of MoO3 considerably decreased the photocatalytic reaction of TiO2. For the estimation of superhydrophilicity, the change of contact angles between the water drop and the film surface was measured as a function of UV-irradiation time. The measured contact angle of WO3-TiO2 film was considerably lower than that of TiO2 before the UV-irradiation, and it decreased to the minimum value about 4 times faster than that of pure TiO2 films with the irradiation of UV light. On the other hand, MoO3-TiO2 films showed a low contact angle at initial point, but their contact angle was very slowly decreased under the UV light. The initial low contact angles suggest the high hydrophilic character of WO3-TiO2 and MoO3-TiO2 films with high Lewis surface acidities. The observed trend suggests that the superhydrophilicity is closely related to the photocatalytic activity.

scholarly journals Influence of Annealing and UV Irradiation on Hydrophilicity of Ag- Nanostructured Thin Films

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Fanming Meng ◽  
Zhaoqi Sun ◽  
Xueping Song
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Contact Angle ◽  
Water Contact Angle ◽  
Uv Irradiation ◽  
Annealing Time ◽  
Irradiation Time ◽  
Ambient Air ◽  
Water Contact ◽  
Nanostructured Thin Films

Ag-TiO2nanostructured thin films with silver content of 5 vol% have been deposited on silicon, glass, and quartz substrates by RF magnetron sputtering and annealed in ambient air at 900°C for 15, 30, 60, 90, and 120 min. Their crystal structure, surface morphology, and hydrophilicity have been characterized by X-ray diffractometer, atomic force microscope, and water contact angle apparatus, respectively. The influence of annealing time and UV irradiation time on hydrophilic property of Ag-TiO2thin films have been studied in detail. It is shown that annealing time influences crystal structure of Ag-TiO2thin films. The unannealed film is amorphous and shows poor hydrophilicity. With the increase of annealing time from 15 to 120 min, the grain-size slowly increases and tends to uniformity. A suitable annealing time can significantly enhance the hydrophilic behavior of Ag-TiO2films. Water contact angle decreases with the increase of irradiation time. The mechanism of hydrophilicity has been proposed and can be attributed to the increase of oxygen anion radicals and reactive center of surface .

Degradation of PVDF-based composite membrane and its impacts on membrane intrinsic and separation properties

2016 ◽  
Vol 36 (3) ◽  
pp. 261-268 ◽  
Author(s):  
Mei Jiun Lee ◽  
Chi Siang Ong ◽  
Woei Jye Lau ◽  
Be Cheer Ng ◽  
Ahmad Fauzi Ismail ◽  
...  
Keyword(s):  
Uv Irradiation ◽  
Exposure Time ◽  
Composite Membrane ◽  
Polyvinylidene Fluoride ◽  
Uv Light ◽  
Irradiation Time ◽  
Uv Exposure ◽  
Polymeric Membrane ◽  
Permeate Flux ◽  
Wastewater Treatment Process

Abstract In this work, an attempt was made to evaluate the effects of ultraviolet (UV) irradiation period on the intrinsic and separation properties of composite membrane composed of organic polyvinylidene fluoride and inorganic titanium dioxide (TiO2) nanoparticles by exposing the membrane to UV-A light for up to 250 h. The changes on membrane structural morphologies and chemical characteristics upon UV exposure were studied by field-emission scanning electron microscope and Fourier transform infrared, respectively. It was observed that some cracks and fractures were formed on the membrane outer surface when it was exposed to 120-h UV light. Further increase in UV irradiation time to 250 h had caused membrane structure to collapse, turning it into powder form. Filtration experiments showed that the permeate flux of irradiated membrane was significantly increased from 10.89 L/m2 h to 21.84 L/m2 h (>100% flux increment) while oil rejection decreased with increasing UV exposure time from 0 h to 120 h. Furthermore, the mechanical strength and thermal stability of irradiated membrane were also reported to decrease with increasing UV exposure time, suggesting the negative impacts of UV light on the membrane overall stability. This research is of particular importance to evaluate the suitability and sustainability of polymeric membrane, which is widely considered as the host for photocatalyts and used for wastewater treatment process under UV irradiation.

Fabrication of Ultrahydrophobic ZnO by Vapor Phase Transport

2011 ◽  
Vol 282-283 ◽  
pp. 753-756
Author(s):  
Zhi Jun Xi ◽  
Gang Li ◽  
Li Ming Lu
Keyword(s):  
Contact Angle ◽  
Vapor Phase ◽  
Film Surface ◽  
Contact Angles ◽  
Nickel Surface ◽  
Zno Film ◽  
Vapor Phase Transport ◽  
Si Substrates ◽  
Vapor Phase Transport Method ◽  
Phase Transport

A ultrahydrophobic ZnO film was synthesized on the Si substrates by a novel vapor phase transport method. The surface structural properties of as-synthesized ZnO film was characterized using scanning electron micrograph (SEM). The contact angles and the rolling angles on such films were measured through an optical contact angle meter. Wettability studies revealed the films exhibited a ultrahydrophobic behaviour with a higher contact angle of 166.8°±6.8° and lower rolling angle of less than 2°-a water droplet moved easily on the surface. SEM showed that compared with pure smooth nickel surface, a lotus-like structrure with micro-nano hierarchical papillae was obviously observed on the ultrahydrophobic ZnO film surface. Such a speccial surface microstructure may result in the ultrahydrophobicity.

Magnetic field assisted photocatalytic degradation of organic dyes in the presence of Ag/TiO2 coated composite

2013 ◽  
Vol 67 (4) ◽  
pp. 722-728 ◽  
Author(s):  
Jian Wang ◽  
Jingqun Gao ◽  
Jun Wang ◽  
Yu Zhai ◽  
Zhongxing Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Rotational Speed ◽  
Organic Dyes ◽  
Dye Degradation ◽  
Uv Light ◽  
Irradiation Time ◽  
Sol Gel ◽  
Heat Treated

Ag/TiO2 coated composite was prepared via sol-gel method in order to elucidate its application in magnetic field assisted photocatalytic degradation of dyes. Through the degradation of organic dyes, the key influences such as Ag amount, heat-treated temperature and time on the photocatalytic activity of Ag/TiO2, as well as UV irradiation time, rotational speed, dye concentration and magnetic sheet number on the photocatalytic degradation were studied. Results showed that the Ag/TiO2 with 25 wt% Ag content heat-treated at 550 °C for 60 min has the best photocatalytic activity. With the increase of UV light irradiation time, rotational speed and magnetic sheet number, the degradation rate is improved. Different dye degradation proved that the method could universally be used.

scholarly journals Ultraviolet irradiation improves the hydrophilicity and osteo-conduction of hydroxyapatite

2020 ◽  
Author(s):  
Sho Kaneko ◽  
Yuji Yamamoto ◽  
Kaniichro Wada ◽  
Gentaro Kumagai ◽  
Yoshifumi Harada ◽  
...  
Keyword(s):  
Contact Angle ◽  
Uv Irradiation ◽  
Uv Light ◽  
Water Drop ◽  
Area Ratio ◽  
Bone Volume ◽  
High Porosity ◽  
Bone Area ◽  
Dental Surgery ◽  
Significant Difference

Abstract Background Treating a titanium or titanium alloy implant with ultraviolet (UV) light is known to improve its associated cell growth and osseointegration. However, little is known about the effect of UV irradiation on hydroxyapatite (HA), which is also used frequently in orthopaedic and dental surgery. Here we examined the effect of UV irradiation on the hydrophilicity of HA, and on its osteoconduction ability in rats. Methods HA implants of low and high porosity were treated with UV light, and photofunctionalisation was assessed by the contact angle of a water drop on the surface. HA implants were also inserted into rat femurs, and the rats were killed two or four weeks later. The bone volume and bone area ratio were calculated from microcomputed tomography and histological data. Results The contact angle of a water drop on HA implants of both porosities was significantly reduced after UV irradiation. In the rat femurs, there was no significant difference in the bone volume between the UV light-treated and control implants at two or four weeks. The bone area ratio for the UV light-treated versus control implants was significantly increased at two weeks, but there was no significant difference at four weeks. Conclusions The surface of UV-irradiated HA disks was hydrophilic, in contrast to that of non-irradiated HA disks. Photofunctionalisation accelerated the increase in the bone area ratio in the early healing stage. This technology can be applied to surgical cases requiring the early fusion of bone and HA.

scholarly journals Ultraviolet irradiation improves the hydrophilicity and osteo-conduction of hydroxyapatite

2020 ◽  
Author(s):  
Sho Kaneko ◽  
Yuji Yamamoto ◽  
Kaniichro Wada ◽  
Gentaro Kumagai ◽  
Yoshifumi Harada ◽  
...  
Keyword(s):  
Contact Angle ◽  
Uv Irradiation ◽  
Uv Light ◽  
Water Drop ◽  
Area Ratio ◽  
Bone Volume ◽  
High Porosity ◽  
Bone Area ◽  
Dental Surgery ◽  
Significant Difference

Abstract Background: Treating a titanium or titanium alloy implant with ultraviolet (UV) light is known to improve its associated cell growth and osseointegration. However, little is known about the effect of UV irradiation on hydroxyapatite (HA), which is also used frequently in orthopaedic and dental surgery. Here we examined the effect of UV irradiation on the hydrophilicity of HA, and on its osteoconduction ability in rats. Methods: HA implants of low and high porosity were treated with UV light, and photofunctionalisation was assessed by the contact angle of a water drop on the surface. HA implants were also inserted into rat femurs, and the rats were killed two or four weeks later. The bone volume and bone area ratio were calculated from microcomputed tomography and histological data. Results: The contact angle of a water drop on HA implants of both porosities was significantly reduced after UV irradiation. In the rat femurs, there was no significant difference in the bone volume between the UV light-treated and control implants at two or four weeks. The bone area ratio for the UV light-treated versus control implants was significantly increased at two weeks, but there was no significant difference at four weeks. Conclusions: The surface of UV-irradiated HA disks was hydrophilic, in contrast to that of non-irradiated HA disks. Photofunctionalisation accelerated the increase in the bone area ratio in the early healing stage. This technology can be applied to surgical cases requiring the early fusion of bone and HA.

Nanotribological Investigation of Magnetic Rigid Disks Lubricated with Perfluoropolyether Lubricant Under Varying Conditions

2008 ◽  
Vol 8 (5) ◽  
pp. 2719-2723 ◽  
Author(s):  
E. Liu ◽  
K. S. Tan ◽  
H. I. Tan
Keyword(s):  
Mechanical Properties ◽  
Uv Irradiation ◽  
Uv Light ◽  
Irradiation Time ◽  
Experimental Results ◽  
Light Irradiation ◽  
Loading Conditions ◽  
Uv Treatment ◽  
Uv Light Irradiation ◽  
Rigid Disks

This paper studies the nanotribological behavior of magnetic rigid disks dip-coated with ultra thin perfluoropolyether (PFPE) Z-Dol 4000 lubricant layers up to 4 nm thick prior to or after exposure to ultraviolet (UV) light irradiation. Lube bonding ratios (LBRs) of 43–91% were achieved by varying the UV irradiation time. The nanotribological and mechanical properties of the disks were measured with a nanotribometer under varying loading conditions. The effect of the LBR on the nanotribological behavior of the disks was also elucidated. We found that the lubricated disks after UV treatment performed better compared to the lubricated disks without UV treatment. The experimental results indicated that the LBR of about 50% could achieve the best contact-start–stop and flyability performances.

Photocatalytic Decolorization of Dyes for Nano-Structures of Titanium Dioxide (TiO2) Films

2010 ◽  
Vol 93-94 ◽  
pp. 603-606 ◽  
Author(s):  
K. Hathaisamit ◽  
W. Pengmula ◽  
T. Wesamula ◽  
Sayan Pudwat
Keyword(s):  
Titanium Dioxide ◽  
Uv Irradiation ◽  
Organic Dyes ◽  
Irradiation Time ◽  
Tio2 Films ◽  
Dc Magnetron Sputtering ◽  
Peak Wavelength ◽  
Photocatalytic Decolorization ◽  
Nano Structures ◽  
Photocatalytic Activities

Application of nano-structures of titanium dioxide (TiO2) films on photocatalytic activities of organic dyes was investigated. Methylene blue (MB) and cation yellow X-Gl 200% were used as organic dyes to observe decolorization. The TiO2 films were prepared on glass substrate by reactive DC magnetron sputtering. The films had thickness, grain size and root mean square surface roughness of 300 nm,  40 nm and  4 nm, respectively. Coated-TiO2 on glass and uncoated TiO2 (glass) were immerged in MB and cation yellow dyes solution. A weak ultraviolet (UV) A at peak wavelength  365 nm and intensity of 0.19 mW/cm2 was irradiated. Absorbance spectra of dyes at different UV irradiation time were observed. The efficiency of decolorization increased as UV irradiation time increased. At UV irradiation time 120 hours, coated-TiO2 showed higher percentage decolorization of MB than uncoated-TiO2 about 64%. While, at UV irradiation time 48 hours, coated-TiO2 showed higher percentage decolorization of cation yellow than uncoated-TiO2 about 84%. Under photocatalysis process of TiO2 films, at the end, MB (about 120 hours) and cation yellow dyes (about 48 hours) change to be colorless.

Aging Behavior of the Polyether Polyurethane Films Irradiated by UV

2013 ◽  
Vol 748 ◽  
pp. 16-21 ◽  
Author(s):  
Hai Yan Wang ◽  
Yu Wen Liu ◽  
Bin Sun ◽  
Shi Jie Huang ◽  
Ji Feng Tian
Keyword(s):  
Aromatic Ring ◽  
Uv Irradiation ◽  
Uv Light ◽  
Irradiation Time ◽  
Color Difference ◽  
Molecular Structures ◽  
Hydroxyl Group ◽  
Failure Behavior ◽  
Polyurethane Film

The failure behavior of polyether polyurethane films irradiated by UV depends on its molecular structures evolvement. The molecular structure evolvement of the polyether polyurethane films under UV irradiation were studied by in-situ FTIR spectra in this paper. It has been found that some oxygen contained groups such as hydroxyl group and carbonyl group increase; on the contrary, ether bond and CH2 decrease with the UV irradiation time. The aromatic ring maintains changeless. However, -NH group has not be determined due to the interference of the-OH and O-C=O. Results from FTIR and SEM have shown that UV photodegradative processes participated by oxidization occur mostly in ether segments and is accompanied by crosslinkage. Using the absorbance band of aromatic ring as the base the service life of polyether polyurethane can be determined by the change rate of C-O-C and-CH2 during UV irradiation. After UV irradiation, the polyether polyurethane film has higher color difference value and lower UV light transparence.

Evaluation of Modified Poly by UV-Induced Graft Polymerization as a Novel Hydrophilic Films

2013 ◽  
Vol 815 ◽  
pp. 594-598
Author(s):  
Bing Qiang Wang
Keyword(s):  
Contact Angle ◽  
Original Film ◽  
Graft Polymerization ◽  
Irradiation Time ◽  
Film Surface ◽  
Ferrous Ammonium Sulfate ◽  
Water Mixture ◽  
Static Contact ◽  
Ferrous Ammonium ◽  
Grafting Degree

In order to improve the hydrophilic performances, the surface of poly films was modified through grafting polymerization of styrene (ST) initiated by ultraviolet (UV) in ethanol/water mixture solution. The effects of irradiation time, concentration of inhibitor (ferrous ammonium sulfate) on the grafting degree of ST will be investigated. The original and grafted poly films were characterized by scanning electron microscopy (SEM) and Static contact angle (CA), to characterize the chemical changes of the poly film surface. The results showed that the hydrophilic of poly films was improved significantly than that of the original film. The contact angle of PO-g-ST increased from 70° to 120.4° over a critical grafting degree of 26.35%, the hydrophilic of PP membranes improved dramatically.

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