scholarly journals Surface Properties of Spray-Assisted Layer-By-Layer ElectroStatic Self-Assembly Treated Wooden Take-Off Board

2021 ◽  
Vol 11 (2) ◽  
pp. 836
Author(s):  
Yi Wan ◽  
Sijie Hou ◽  
Mengyao Guo ◽  
Yanchun Fu
Keyword(s):  
Self Assembly ◽  
Treated Wood ◽  
Contact Angles ◽  
Water Repellent ◽  
Layer By Layer ◽  
Air Exposure ◽  
Limiting Oxygen Index ◽  
Sodium Phytate ◽  
Static Contact ◽  
Combustion Tests

Wooden take-off board is easy to crack, deform, discolor, and decay when it is used outdoors, which not only increases maintenance costs but also reduces its service life. Multifunctional coatings with UV-resistant, water-repellent, and flame-retardant properties were successfully obtained on the surface of a wooden take-off board substrate by spray-assisted layer-by-layer self-assembly. The coatings consisted of positively-charged chitosan, Al (OH)3, and negatively-charged sodium phytate through electrostatic adsorption several times. The treated wood exhibited high UV resistance, and the color remained constant after 720 hours of ultraviolet irradiation. The wettability of the wood surface after treatment became superhydrophobic, with initial static contact angles as high as 140°. In addition, limiting oxygen index and air exposure combustion tests were used to verify that chitosan, sodium phytate, and aluminum hydroxide could synergistically confer significant fire resistance to modified wood.

scholarly journals Preparation and Synergistic Effect of Chitosan/Sodium Phytate/MgO Nanoparticle Fire-Retardant Coatings on Wood Substrate through Layer-By-Layer Self-Assembly

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 848 ◽  
Author(s):  
Feiyue Zhao ◽  
Tingli Tang ◽  
Sijie Hou ◽  
Yanchun Fu
Keyword(s):  
Self Assembly ◽  
Energy Dispersive Spectrometry ◽  
Oxygen Index ◽  
Fire Retardant ◽  
Layer By Layer ◽  
Wood Substrate ◽  
Limiting Oxygen Index ◽  
Mgo Nanoparticles ◽  
Sodium Phytate ◽  
Mgo Nanoparticle

Fire-retardant chitosan/sodium phytate/MgO nanoparticle (CH/SP/nano-MgO) coatings were loaded on a wood substrate via electrostatic layer-by-layer self-assembly and characterized by scanning electron microscopy and energy-dispersive spectrometry. The flammability and thermal degradation of the original wood and wood samples treated with chitosan, chitosan/sodium phytate, chitosan/sodium phytate/MgO nanoparticles were studied by limiting oxygen index (LOI), exposure combustion experiments and thermogravimetric analysis (TGA), respectively. The CH/SP/nano-MgO coating served as an intumescent fire-retardant system that created a physical protection cover and exhibited the best fire retardant performance. The LOI value was 30.2% and required approximately 16–17 s to self-extinguish when exposed to air. The TGA curves also showed that char formation protected the wood from combustion.

scholarly journals Flame-Retardant Wood Composites Based on Immobilizing with Chitosan/Sodium Phytate/Nano-TiO2-ZnO Coatings via Layer-by-Layer Self-Assembly

Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 296 ◽  
Author(s):  
Lin Zhou ◽  
Yanchun Fu
Keyword(s):  
Flame Retardant ◽  
Flame Retardancy ◽  
Self Assembly ◽  
Composite Coatings ◽  
Wood Products ◽  
Layer By Layer ◽  
Zno Nanoparticle ◽  
Nano Tio2 ◽  
Limiting Oxygen Index ◽  
Sodium Phytate

Composite coatings of inorganic nanomaterials with polyelectrolytes are promising materials for wood modification. Endowing wood with flame retardancy behavior can not only broaden the range of applications of wood, but also improve the safety of wood products. In this work, chitosan/sodium phytate/TiO2-ZnO nanoparticle (CH/SP/nano-TiO2-ZnO) composite coatings were coated on wood surface through layer-by-layer self-assembly. The morphology and chemical composition of the modified wood samples were analyzed using scanning electron microscopy and energy dispersive spectrometry. The thermal degradation properties and flame retardancy of the samples treated with different assembly structures were observed by thermogravimetric analysis, limiting oxygen test, and combustion test. Due to the presence of an effective intumescent flame retardant system and a physical barrier, the CH/SP/nano-TiO2-ZnO coatings exhibited the best flame retardant performance and required only approximately six seconds for self-extinguishing. The coated samples had a limiting oxygen index of 8.4% greater than the original wood.

scholarly journals Fluorosilane Water-Repellent Coating for the Protection of Marble, Wood and Other Materials

Heritage ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 2668-2675
Author(s):  
Fotios G. Adamopoulos ◽  
Evangelia C. Vouvoudi ◽  
Dimitris S. Achilias ◽  
Ioannis Karapanagiotis
Keyword(s):  
Polymer Networks ◽  
Treated Wood ◽  
Water Repellency ◽  
Contact Angles ◽  
Water Repellent ◽  
Capillary Absorption ◽  
Durability Test ◽  
Water Contact ◽  
Produce Water ◽  
The Aesthetic

The preservation of cultural heritage monuments and artifacts requires the development of methods to produce water-repellent materials, which can offer protection against the effects of atmospheric water. Fluorosilanes are a very promising class of materials, as they act as precursors for the formation of low surface energy polymer networks. 1H,1H,2H,2H-perfluorooctyl-triethoxysilane is applied on marble, wood and the surfaces of other materials, such as glass, silicon wafer, brass, paper and silk. According to the measurements of static water contact angles, it is reported that superhydrophobicity and enhanced hydrophobicity are achieved on the surfaces of coated marble and wood, respectively. Hydrophobicity and hydrophilicity were observed on the treated surfaces of the other materials. More important, water repellency is achieved on any hydrophobic or superhydrophobic surface, as revealed by the very low sliding angles of water drops. The study is accompanied by colorimetric measurements to evaluate the effects of the treatment on the aesthetic appearances of the investigated materials. Finally, the capillary absorption test and a durability test are applied on treated wood and marble, respectively. 

scholarly journals Thermal Atomic Layer Deposition of Yttrium Oxide Films and Their Properties in Anticorrosion and Water Repellent Coating Applications

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 497
Author(s):  
Christian Dussarrat ◽  
Nicolas Blasco ◽  
Wontae Noh ◽  
Jooho Lee ◽  
Jamie Greer ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Yttrium Oxide ◽  
Photoelectron Spectroscopy ◽  
Silicon Oxide ◽  
Atomic Layer ◽  
Contact Angles ◽  
Water Repellent ◽  
Water Contact ◽  
Air Exposure ◽  
Layer Deposition

The thermal atomic layer deposition (ThALD) of yttrium oxide (Y2O3) was developed using the newly designed, liquid precursor, Y(EtCp)2(iPr2-amd), as the yttrium source in combination with different oxygen sources, such as ozone, water and even molecular oxygen. Saturation was observed for the growth of the Y2O3 films within an ALD window of 300 to 450 °C and a growth per cycle (GPC) up to 1.1 Å. The resulting Y2O3 films possess a smooth and crystalline structure, while avoiding any carbon and nitrogen contamination, as observed by X-ray photoelectron spectroscopy (XPS). The films showed strong resistance to fluorine-containing plasma, outperforming other resistant materials, such as silicon oxide, silicon nitride and alumina. Interestingly, the hydrophilic character exhibited by the film could be switched to hydrophobic after exposure to air, with water contact angles exceeding 90°. After annealing under N2 flow at 600 °C for 4 min, the hydrophobicity was lost, but proved recoverable after prolonged air exposure or intentional hydrocarbon exposure. The origin of these changes in hydrophobicity was examined.

scholarly journals Formation of Chitosan/Sodium Phytate/Nano-Fe3O4 Magnetic Coatings on Wood Surfaces via Layer-by-Layer Self-Assembly

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 51 ◽  
Author(s):  
Tingli Tang ◽  
Yanchun Fu
Keyword(s):  
Wood Surface ◽  
Self Assembly ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Chitosan Solution ◽  
Layer By Layer ◽  
Nanoparticle Suspension ◽  
Sodium Phytate ◽  
Assembly Method ◽  
Modified Wood

Magnetic wood would have potential uses in electromagnetic shielding and electromagnetic wave absorption. In this paper, magnetic coatings on a wood surface were synthesized using a layer-by-layer self-assembly method. As the cationic polyelectrolyte carrier, natural macromolecular chitosan was pre-immobilized on a wood surface first, followed by the alternate adsorption of anionic polyelectrolyte sodium phytate and positively-charged Fe3O4 nanoparticles. The concentration of pH-controlled chitosan solution, sodium phytate solution, and Fe3O4 nanoparticle suspension, soaking time, and the number of alternating sedimentary layers varied. The morphology and crystal structure of the Fe3O4 modified wood samples were studied using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The magnetic hysteresis loops showed that the modified wood had magnetic properties which were improved as the number of assembled layers increased.

scholarly journals Superhydrophobic Coatings Based on Siloxane Resin and Calcium Hydroxide Nanoparticles for Marble Protection

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 334 ◽  
Author(s):  
Aikaterini Chatzigrigoriou ◽  
Ioannis Karapanagiotis ◽  
Ioannis Poulios
Keyword(s):  
Electron Microscopy ◽  
Calcium Hydroxide ◽  
Composite Coatings ◽  
Exchange Process ◽  
Sio2 Nanoparticles ◽  
Contact Angles ◽  
Water Repellent ◽  
Aqueous Emulsion ◽  
Aesthetic Appearance ◽  
Static Contact

Calcium hydroxide (Ca(OH2)) nanoparticles are produced following an easy, ion exchange process. The produced nanoparticles are characterized using transmission electron microscopy (TEM) and Fourier- transform infrared spectroscopy (FTIR) and are then dispersed in an aqueous emulsion of silanes/siloxanes. The dispersions are sprayed on marble and the surface structures of the deposited coatings are revealed using scanning electron microscopy (SEM). By adjusting the nanoparticle concentration, the coated marble obtains superhydrophobic and water repellent properties, as evidenced by the high static contact angles of water drops (> 150°) and the low sliding angles (< 10°). Because Ca(OH)2 is chemically compatible with limestone-like rocks, which are the most common stones found in buildings and objects of the cultural heritage, the produced composite coatings have the potential to be used for conservation purposes. For comparison, the wetting properties of another superhydrophobic and water repellent coating composed of the same siloxane material and silica (SiO2) nanoparticles, which were commonly used in several previously published reports, were investigated. The suggested siloxane+Ca(OH)2 composite coating offers good protection against water penetration by capillarity and has a small effect on the aesthetic appearance of marble, according to colorimetric measurements.

scholarly journals Facile Method to Prepare Superhydrophobic and Water Repellent Cellulosic Paper

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Ioannis Karapanagiotis ◽  
Diana Grosu ◽  
Dimitra Aslanidou ◽  
Katerina E. Aifantis
Keyword(s):  
Particle Concentration ◽  
Water Repellency ◽  
Contact Angles ◽  
Water Repellent ◽  
Tissue Paper ◽  
Nanoparticle Films ◽  
High Particle ◽  
Aesthetic Appearance ◽  
Static Contact ◽  
Wide Range

Silica nanoparticles (7 nm) were dispersed in solutions of a silane/siloxane mixture. The dispersions were applied, by brush, on four types of paper: (i) modern, unprinted (blank) paper, (ii) modern paper where a text was printed using a common laser jet printer, (iii) a handmade paper sheet detached from an old book, and (iv) Japanese tissue paper. It is shown that superhydrophobicity and water repellency were achieved on the surface of the deposited films, when high particle concentrations were used (≥1% w/v), corresponding to high static (θS≈ 162°) and low tilt (θt< 3°) contact angles. To interpret these results, scanning electron microscopy (SEM) was employed to observe the surface morphologies of the siloxane-nanoparticle films. Static contact angles, measured on surfaces that were prepared from dilute dispersions (particle concentration <1% w/v), increased with particle concentration and attained a maximum value (162°) which corresponds to superhydrophobicity. Increasing further the particle concentration did not have any effect onθS. Colourimetric measurements showed that the superhydrophobic films had negligible effects on the aesthetic appearance of the treated papers. Furthermore, it is shown that the superhydrophobic character of the siloxane-nanoparticle films was stable over a wide range of pH.

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