Transparent and Hydrophilic TiO2 Anatase as Top-Protective Layer for CSP Reflectors

2015 ◽  
Vol 1119 ◽  
pp. 355-359 ◽  
Author(s):  
Houda Ennaceri ◽  
Asmae Khaldoun ◽  
Abdelilah Benyoussef ◽  
Tristan Köhler ◽  
Rodrigo Sáez-Araoz ◽  
...  
Keyword(s):  
Contact Angle ◽  
Organic Contaminants ◽  
Near Infrared ◽  
Protective Layer ◽  
Industrial Applications ◽  
Water Contact ◽  
Specular Reflectance ◽  
Glass Substrates ◽  
Photo Catalysis ◽  
Angle Measurements

Titanium Dioxide is an important material that is used in many industrial applications such as photo-catalysis, glass-defogging, self-cleaning, waste water purification and anti-bacterial sterilization. The strong photo-catalysis of TiO2, and therefore its ability to decompose dirt and organic contaminants makes it an excellent top-protective layer candidate for CSP reflectors. The aim of this study consists of the deposition of a transparent and hydrophilic TiO2layer on top of the Concentrated Solar Power (CSP) mirrors without altering their specular reflectance. The strong photo-catalysis and hydrophilicity of TiO2will decompose the dirt and organic matter on the surface of the mirrors, which would be cleaned away from the reflectors’ surface by rain, therefore minimizing the use of water for cleaning the CSP mirrors.In this study, polycrystalline anatase TiO2layers were deposited on glass substrates with different thicknesses. The contact angle measurements show that the hydrophilicity of TiO2increases with increasing surface roughness, with Water Contact Angle (WCA) of 52°and 30° for 48 nm and 100 nm, respectively. Super-hydrophilicity (WCA < 5°) was achieved for thicker TiO2layers, with WCA of 8° and 1° for 177 nm and 220 nm, respectively. The deposition of a 48 nm-thick TiO2layer on glass showed a high transmittance in the visible and Near Infrared (NIR) range (75%), whereas the transmission decreased with increasing thicknesses of TiO2. Therefore, a TiO2layer of 48 nm thickness is suggested in this study as a hydrophilic top-protective layer since it preserved the specular reflectance of the mirrors (97.5%) in the NIR range, compared to 98.6% without the TiO2layer.

scholarly journals Synthesis, Hydrophilicity and Micellization of Coil–Brush Polystyrene-b-(polyglycidol-g-polyglycidol) Copolymer—Comparison with Linear Polystyrene-b-Polyglycidol

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 253
Author(s):  
Mariusz Gadzinowski ◽  
Maciej Kasprów ◽  
Teresa Basinska ◽  
Stanislaw Slomkowski ◽  
Łukasz Otulakowski ◽  
...  
Keyword(s):  
Contact Angle ◽  
Self Assembly ◽  
Original Method ◽  
Critical Micellization Concentration ◽  
Water Contact ◽  
1H And 13C Nmr ◽  
Similar Composition ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Static Conditions

In this paper, an original method of synthesis of coil–brush amphiphilic polystyrene-b-(polyglycidol-g-polyglycidol) (PS-b-(PGL-g-PGL)) block copolymers was developed. The hypothesis that their hydrophilicity and micellization can be controlled by polyglycidol blocks architecture was verified. The research enabled comparison of behavior in water of PS-b-PGL copolymers and block–brush copolymers PS-b-(PGL-g-PGL) with similar composition. The coil–brush copolymers were composed of PS-b-PGL linear core with average DPn of polystyrene 29 and 13 of polyglycidol blocks. The DPn of polyglycidol side blocks of coil–b–brush copolymers were 2, 7, and 11, respectively. The copolymers were characterized by 1H and 13C NMR, GPC, and FTIR methods. The hydrophilicity of films from the linear and coil–brush copolymers was determined by water contact angle measurements in static conditions. The behavior of coil–brush copolymers in water and their critical micellization concentration (CMC) were determined by UV-VIS using 1,6-diphenylhexa-1,3,5-trien (DPH) as marker and by DLS. The CMC values for brush copolymers were much higher than for linear species with similar PGL content. The results of the copolymer film wettability and the copolymer self-assembly studies were related to fraction of hydrophilic polyglycidol. The CMC for both types of polymers increased exponentially with increasing content of polyglycidol.

Influence of TiO2 on Selfclean Bio Coating

2013 ◽  
Vol 315 ◽  
pp. 399-403 ◽  
Author(s):  
Nurulsaidatulsyida Sulong ◽  
Anika Zafiah Mohd Rus
Keyword(s):  
Contact Angle ◽  
Organic Contaminants ◽  
Concrete Surface ◽  
Waste Cooking Oil ◽  
Water Repellent ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
The Difference ◽  
Micro Features ◽  
Coated Surfaces

Treatment on the exposed surface to the environmental attack was studied based on biopolymer coating from waste cooking oil doped with a superhydrophilic filler of Titanium Dioxide (TiO2), known as TOP. TOP was found to affect the physical properties of the coated concrete surface in a systematic way. Contact angle measurements are interpreted with respect to nanoand micro-features existing on the surface of the water repellent superhydrophilic filler filled bio-polymer composite coating. The smooth coated surfaces of polymer filled or doped with superhydrophobic filler shows the systematic increasing static Waste Contact Angle, WCA (θst) and revealed that polymer filled superhydrophobic fillers by only 2.0 % shows the ability to form superhydrophobicity property. Scanning Electron Microscope (SEM) pictures revealed the difference between the concrete surface roughness of concrete biopolymer with and without TOP coating is to provide self-cleaning concrete biopolymer coating based on two principal ways: (1) the development of surface coating of semiconducting photocatalytic superhydrophilic. (2) If such a superhydrophilic is illuminated by light, then grease, dirt and organic contaminants will be decomposed and can easily be swept away by rain.

Non-woven Membranes Electrospun from Polylactic Acid Incorporating Silver Nanoparticles as Biocide

2012 ◽  
Vol 1376 ◽  
Author(s):  
Haydee Vargas-Villagran ◽  
Elvia Teran-Salgado ◽  
Maraolina Dominguez-Diaz ◽  
Osvaldo Flores ◽  
Bernardo Campillo ◽  
...  
Keyword(s):  
Contact Angle ◽  
Silver Nanoparticles ◽  
Polylactic Acid ◽  
Chloroform Solution ◽  
Average Diameter ◽  
Electrospinning Process ◽  
Water Contact ◽  
X Ray Scattering ◽  
Angle Measurements ◽  
Contact Angle Measurements

ABSTRACTIn this research, we describe the electrospinning processing of polylactic acid (PLA) and the influence of silver nanoparticles on the morphology and microstructure of produced non woven membranes thus produced. The PLA was electrospun from a chloroform solution and a filamentary and granular morphology was obtained, the filaments having an average diameter of 1.25 μm, When silver nanoparticles (of ca. 12 nm size) were incorporated, the filaments diameter was reduced to an average of 0.65 μm, and the density of beads was also reduced. The membranes were rather amorphous, as revealed by X-ray scattering, presumably due to the quenching process associated with the electrospinning process. Water contact angle measurements showed that silver nanoparticles induced significant hidrophobicity in the membranes as neat PLA membrane had a contact angle of 54° and PLA/Ag membrane exhibited an angle of 115°.

scholarly journals Strategies to Improve the Properties of Amaranth Protein Isolate-Based Thin Films for Food Packaging Applications: Nano-Layering through Spin-Coating and Incorporation of Cellulose Nanocrystals

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2564
Author(s):  
Amparo López-Rubio ◽  
Adriana Blanco-Padilla ◽  
Kristiina Oksman ◽  
Sandra Mendoza
Keyword(s):  
Contact Angle ◽  
Optical Properties ◽  
Cellulose Nanocrystals ◽  
Spin Coating ◽  
Food Packaging ◽  
Water Solubility ◽  
Protein Isolate ◽  
Water Soluble ◽  
Water Contact ◽  
Angle Measurements

In this work, two different strategies for the development of amaranth protein isolate (API)-based films were evaluated. In the first strategy, ultrathin films were produced through spin-coating nanolayering, and the effects of protein concentration in the spin coating solution, rotational speed, and number of layers deposited on the properties of the films were evaluated. In the second strategy, cellulose nanocrystals (CNCs) were incorporated through a casting methodology. The morphology, optical properties, and moisture affinity of the films (water contact angle, solubility, water content) were characterized. Both strategies resulted in homogeneous films with good optical properties, decreased hydrophilic character (as deduced from the contact angle measurements and solubility), and improved mechanical properties when compared with the neat API-films. However, both the processing method and film thickness influenced the final properties of the films, being the ones processed through spin coating more transparent, less hydrophilic, and less water-soluble. Incorporation of CNCs above 10% increased hydrophobicity, decreasing the water solubility of the API films and significantly enhancing material toughness.

Hydrophobic Performance of Core/Shell Nanoarrays Modified by Stearic Acid

2020 ◽  
Vol 15 (2) ◽  
pp. 264-268
Author(s):  
Hongxing Han ◽  
Lin Pan ◽  
Manying Zhang ◽  
Lei Zhao ◽  
Zhifeng Liu
Keyword(s):  
Contact Angle ◽  
Stearic Acid ◽  
Water Contact Angle ◽  
Zno Nanorods ◽  
Hydrophobic Surface ◽  
Optical Transmittance ◽  
Surface Hydrophobicity ◽  
Core Shell ◽  
Water Contact ◽  
Angle Measurements

In this paper, we successfully prepare hydrophobic surface of ZnO/ZnS nanorods arrays modified by stearic acid. The morphology, microstructure, optical transmittance and self-cleaning property are examined by SEM, XRD, UV-vis and water contact angle measurements, respectively. The ZnO/ZnS core/shell nanoarrays shows a higher value of water contact angle in compare with that of pure ZnO nanorods arrays. After treatment by stearic acid, the resulting ZnO/ZnS nanostructure exhibits the best hydrophobicity with water droplets about 146.5 . The results show that the surface hydrophobicity of ZnO/ZnS nanoarrays can be improved by using stearic acid with low-surface-energy.

scholarly journals Preparation and characterization of polyethylene glycol/poly(L-lactic acid) blends

2017 ◽  
Vol 89 (1) ◽  
pp. 141-152 ◽  
Author(s):  
Ioanna-Georgia Athanasoulia ◽  
Petroula A. Tarantili
Keyword(s):  
Contact Angle ◽  
Lactic Acid ◽  
Degradation Process ◽  
Water Contact ◽  
Wetting Ability ◽  
Angle Measurements ◽  
Low Concentrations ◽  
Contact Angle Measurements ◽  
Twin Screw ◽  
Poly Ethylene

AbstractThe effect of incorporation of poly(ethylene glycol) (PEG) on thermomechanical and hydrophilicity properties of poly(L-lactic acid) (PLLA) was investigated. PEG/PLLA blends, containing 10, 20, 30 and 40 wt% PEG, were prepared by melt-extrusion in a co-rotating twin-screw extruder. By DSC analysis, it was observed that the Tg of PLLA phase in PEG/PLLA blends decreased accompanied by a significant decrease in Tcc and increase in their melting enthalpy. Therefore, the addition of PEG enhances the crystallization ability of PLLA phase due to its lubricating effect which increased mobility of PLLA chains. From TGA it was observed that low concentrations of PEG (10 & 20 wt%) increase the Tonset of thermal degradation, probably due to improved heat resistance of the crystalline phase. At higher PEG content, the Tonset decreases, as the lubricating effect becomes the controlling mechanism for the initiation of degradation process. Decrease in tensile strength and modulus was recorded especially in PLLA blends with PEG content higher than 20 wt%. The elongation at break decreases reaching a maximum at 20 wt% PEG and then dropped again. To investigate the effect of PEG on the wetting ability of PLLA, water contact angle measurements were performed. The results indicate that the introduction of PEG lowers the contact angle values in PEG/PLLA film surfaces, as compared to pure PLLA, suggesting improved hydrophilic properties.

scholarly journals Hydrophobic zinc-tellurite glass system as self-cleaning vehicle: Interplay amid SiO2 and TeO2

2018 ◽  
Vol 14 ◽  
pp. 492-494
Author(s):  
Siti Nur Nazhirah Mazlan ◽  
Ramli Arifin ◽  
Sib Krishna Ghoshal
Keyword(s):  
Contact Angle ◽  
Hydrophobic Interactions ◽  
Hydrophobic Surface ◽  
Cost Effective ◽  
Underlying Mechanism ◽  
Industrial Applications ◽  
Glass System ◽  
Preparation Technique ◽  
Water Contact ◽  
Self Cleaning

Cost-effective, environmental amiable and maintenance free glasses with improved hydrophobic activity are needed for diverse industrial applications. Pollutant and dirt depositions on glasses that cause the visual obscurity and damages of the cultural heritages require inhibition. The underlying mechanism of hydrophobic interactions assisted self-cleaning traits of glass is poorly understood. It has been shown that excellent hydrophobic glass with water contact angle (WCA) above 90o and very low surface wettability can be achieved by controlling the surface roughness (SR), where liquid droplets remain perfectly spherical on such surfaces (literally without touching) before being self-cleaned (rolls off). Moreover, selection and optimization of constituent materials composition as well as the preparation technique play a significant role towards such success. Most of the previous attempts for the self-cleaning glass preparation were made via coating strategy on glass surface. Yet, preparation of super-hydrophobic glass surfaces with self-cleaning attributes remains an open challenge. Driven by this idea, we prepared a new glass system of composition (80 x) TeO2-20ZnO-(x)SiO2 (x = 0, 0.03, 0.06, 0.09 and 0.12 mol%) by melt-quenching method, where the proportions of SiO2 and TeO2 were interplayed. As-prepared samples (thin pellet without coating) were characterized using atomic force microscopy (AFM) and video contact angle (VCA) measurements. The effects of SiO2 concentration on the glass SR, surface energy and hydrophobic properties were evaluated. Glass 0.06 mol% of SiO2 revealed the optimal WCA of 112.39º and SR of 7.806 nm. It was established that a trade-off between SiO2 and TeO2 contents in the studied glasses could produce super-hydrophobic surface (WCA over 90º), leading to great opportunities for diverse self-cleaning applications.

Ionizable polyol from cottonseed oil for anionic waterborne polyurethane-silanol dispersions

2019 ◽  
Vol 10 (4) ◽  
pp. 77-94
Author(s):  
Sashivinay Kumar Gaddam ◽  
Aruna Palanisamy
Keyword(s):  
Contact Angle ◽  
Soft Segment ◽  
Testing Machine ◽  
Waterborne Polyurethane ◽  
Cottonseed Oil ◽  
Average Particle ◽  
Water Contact ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Synthetic Methodologies

A novel cottonseed oil-based ionizable polyol was introduced as ionic soft segment in waterborne polyurethane dispersion (PUD) synthesis. The ionizable polyol was synthesized by ring opening of epoxidized cottonseed oil (ECSO) with 4-aminobenzoic acid (PABA) and blended with hydroxylated cottonseed oil polyol (HCSO) in different weight ratios to develop a series of mixed polyols having different hydroxyl numbers viz., 146, 130 and 114 mg KOH/g. Three different PUDs were synthesized using the mixed polyols, isophorone diisocyanate, and 3-aminopropyltriethoxysilane. The chemical structure, thermo-mechanical properties, and surface properties of cured PUD films were examined using Fourier-transform infrared spectroscopy (FTIR), Dynamic mechanical thermal analysis (DMTA), universal testing machine (UTM) and contact angle measurements respectively. The effect of Si–O–Si cross-linking network density, which increases with an increase in OH values of the mixed polyol was also investigated. All the PUDs prepared in this study exhibited good storage stability (>4 months), and the average particle sizes of PUDs ranged from 18 to 124 nm. The highest hydroxyl mixed polyol derived PUD film (PUD-35 film) exhibited high thermal stability, mechanical strength; Tg value, water contact angle value, chemical, and abrasion resistance properties due to the extended siloxane cross-link network structure. The introduction of ionizable polyol into the soft segment led to an improvement in hard and soft segment phase mixing of PUDs, and this strategy could enrich the exploration of new synthetic methodologies in the field of bio-based PUD manufacturing.

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