scholarly journals Water modulates the lamellar structure and interlayer correlation of poly(perfluorooctyl acrylate) films: a specular and off-specular neutron scattering study

2021 ◽  
Author(s):  
Akihisa Yamamoto ◽  
Yuji Higaki ◽  
Judith Thoma ◽  
Esther Kimmle ◽  
Ryohei Ishige ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Osmotic Pressure ◽  
Correlation Length ◽  
Ethyl Acrylate ◽  
Contact Angles ◽  
Water Repellent ◽  
Water Molecules ◽  
Coating Materials ◽  
Water Contact ◽  
Vertical Correlation

AbstractComb-like polymers with pendant-like perfluorocarbon side chains self-assemble into smectic lamellae and have been extensively used as water-repellent, hydrophobic coating materials characterized by large water contact angles (θ > 120°). As poly(perfluorooctyl acrylate) films are “apparently hydrophobic” (θ > 120°), the interaction of such materials and water molecules has been largely overlooked. To unravel the molecular-level interactions between water and apparently hydrophobic polymers, specular and off-specular neutron scattering experiments were conducted at defined osmotic pressure ΠH2O. The poly{2-[(perfluorooctylethyl)carbamate]ethyl} acrylate (PFAUr-C8), which had a carbamate linker, transitioned to another lamellar phase at 89 °C. At T = 25 °C; the lamellar periodicity of PFAUr-C8 slightly increased with decreasing osmotic pressure, while the vertical correlation length increased. However, the poly[(perfluorooctyl)ethyl] acrylate (PFA-C8) that did not contain a carbamate linker directly transitioned to a disordered phase at 84 °C. The lamellar periodicity of PFA-C8 was largely independent of the osmotic pressure, suggesting that PFA-C8 was poorly hydrated. Remarkably, the vertical correlation length decreased with decreasing osmotic pressure. Because hydration facilitated by the linker modulated the smectic lamellae of the poly(perfluoroalkyl acrylate), water molecules could be used to optimize the self-assembly of apparently hydrophobic liquid crystalline polymers.

PVDF Films with Superhydrophobic Surface Fabricated by Plasma-Enhanced Chemical Vapor Deposition

2009 ◽  
Vol 79-82 ◽  
pp. 1451-1454 ◽  
Author(s):  
Zhi Qiu Zhang ◽  
Wen Fang Yang ◽  
Zhen Ya Gu ◽  
Rui Ting Huo
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Film Surface ◽  
Chemical Vapor ◽  
Contact Angles ◽  
Water Repellent ◽  
Treatment Technology ◽  
Water Contact ◽  
Lotus Effect ◽  
Pvdf Membrane

Lotus effect is well-known to be governed by chemical properties and nanotextures of the surfaces. In this paper, a method with two-steps treatment technology was applied to develop the superhydrophobic polyvinylidene fruoride(PVDF) membrane with the property of anti-contamination and self-cleaning. First, the PVDF membrane was treated by oxygen plasma so as to get the reactive groups. Second, this film was deposited by perfluoroalkylethyl acrylate precursor/Ar gas via plasma-enhanced chemical vapor deposition (PECVD). The modified film surface exhibited ultra water-repellent ability, showing that the water contact angles was larger than 150 °and the dynamic contact angles was usually lower than 5°.

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. 

Effect of Annealing Temperature on the Photocatalytic Activity and Hydrophobic Property of TiO2 Nanorod Arrays Prepared by Hydrothermal Method

2018 ◽  
Vol 928 ◽  
pp. 71-76 ◽  
Author(s):  
Peerawas Kongsong ◽  
Nuan La Ong Srakaew ◽  
Phatcharee Phoempoon ◽  
Mahamasuhaimi Masae ◽  
Lek Sikong
Keyword(s):  
Photocatalytic Activity ◽  
Annealing Temperature ◽  
Rutile Phase ◽  
Contact Angles ◽  
Water Molecules ◽  
Nanorod Arrays ◽  
Hydrophobic Property ◽  
Water Contact ◽  
Photocatalytic Activities ◽  
Hydrophobic Nature

TiO2nanorod arrays (TNRs) films were fabricated on the polished Ti substrates using hydrothermal and then annealed for 2 h in air at 300°-500°C. The films were characterized by XRD and FESEM. The photocatalytic activities to degrade methylene blue (MB) in solution were determined, expecting these activities to correlate with the hydrophobic property. The experiment showed that rutile peaks recrystallized at the annealing temperature, with the crystallinity increase with increasing annealing temperatures. The TNRs films annealed at 500 oC had a comparatively high crystallinity of rutile phase as well as the highest photocatalytic activity of the films prepared. Surface wettability was studied by measuring the contact angle of the liquid interface which showed hydrophobic nature as water contact angles were greater than 120°. The results can be concluded that as-prepared TNRs film was annealed at 500 oC exhibits excellent hydrophobicity for water molecules and the highest photocatalytic activity on the degradation of MB under UV irradiation.

The Polymerization and Performance of Fluorinated Acrylic Copolymer with Low Surface Energy

2011 ◽  
Vol 687 ◽  
pp. 562-566
Author(s):  
Yan Zhang ◽  
Zhan Ping Zhang ◽  
Yu Hong Qi ◽  
Xin Rui Gao
Keyword(s):  
Surface Energy ◽  
Monomer Conversion ◽  
Ethyl Acrylate ◽  
Carbon Chain ◽  
Solid Content ◽  
Coating Materials ◽  
Water Contact ◽  
Acrylic Copolymer ◽  
Low Surface Energy ◽  
And Performance

Fluoro-polymer is of great importance as coating materials because of their excellent resistance to high temperature, chemicals and organic solvents. In the interest of researching low surface energy coating, a kind of copolymer was prepared by solution polymerization method, using methyl methacrylate, butyl acrylate, 2-hydroxyethyl acrylate and perfluoroalkyl ethyl acrylate whose length of fluorinated carbon chain was from 6 to12. Solid content, monomer conversion rate and viscosity of the copolymer were measured. Parallel experiments were separately carried out with different contents of initiator and fluorinated monomer. The results showed that the water contact angle of the film becomes bigger with the increase of the content of fluorinated monomer, with the biggest value in 108° when the content of fluorinated monomer content is 30 wt%, but only changing little after content of fluorinated monomer reaches up 15 wt%. The results indicated that the copolymer can offer the best property combination when the contents of fluorinated monomer and initiator were 15 wt% and 1.8 wt%.

Fabrication and Characterization of Ultra Water Repellent Surfaces on Aluminum Alloy Substrate

2016 ◽  
Vol 705 ◽  
pp. 278-282
Author(s):  
Ri Han Chi ◽  
Yue Fei Yu ◽  
Zhi Jia Yu ◽  
Guo Zhu Kuang
Keyword(s):  
Aluminum Alloy ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Water Repellent ◽  
Water Contact ◽  
Hierarchical Roughness ◽  
Silane Coating ◽  
Coating Method ◽  
Sinusoidal Flow

The fabrication of metallic ultra water repellent surfaces is of great significance to many industrial and scientific areas. Ultra water repellent surfaces on aluminum alloy substrates were fabricated with acidic etching and fluoroalkyl silane coating method. The prepared surfaces exhibit good water repellent behaviors with water contact angles (WCA) larger than 150° and contact angle hysteresis (CAH) about 5°. The resultant surfaces were examined using scanning electron microscope (SEM). The results show that a kind of hierarchical roughness in micro-nanoscale is formed, which plays a key role for the fabrication of ultra water repellent surfaces. Fancy phenomena such as "chair-shaped flow", "flow orientation" and "sinusoidal flow" were observed when water flowed in a rectangular conduit constructed with one ultra water repellent wall and one super hydrophilic wall on the opposite side. The observations reveal some characteristics of water flow in ultra water repellent conduits.

scholarly journals Influence of organic manure amendments on water repellency, water entry value, and water retention of soil samples from a tropical Ultisol

2016 ◽  
Vol 64 (2) ◽  
pp. 160-166 ◽  
Author(s):  
T.D.P. Liyanage ◽  
D.A.L. Leelamanie
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Water Retention ◽  
Water Repellency ◽  
Water Entry ◽  
Contact Angles ◽  
Organic Manure ◽  
Water Repellent ◽  
Water Contact ◽  
In Series

AbstractLowered stability of soil aggregates governed by insufficient organic matter levels has become a major concern in Sri Lanka. Although the use of organic manure with water repellent properties lowers the wetting rates and improves the stability of soil aggregates, its effects on soil hydrophysical properties are still not characterized. Therefore, the objective of this study was to examine the relation of water repellency induced by organic manure amendments to the water entry value and water retention of a Sri Lankan Ultisol. The soil was mixed with ground powders of cattle manure (CM), goat manure (GM),Gliricidia maculata(GL) and hydrophobicCasuarina equisetifolia(CE) leaves to obtain samples ranging from non-repellent to extremely water repellent, in two series. Series I was prepared by mixing GL and CE with soil (5, 10, 25, 50%). Series II consisted of 5% CM, GM, and GL, with (set A) and without (set B) intermixed 2% CE. Water repellency, water entry value, and water retention of samples were determined in the laboratory. Soil-water contact angle increased with increasing organic matter content in all the samples showing positive linear correlations. Although the samples amended with CE showed high soil-water contact angles in series I, set A (without 2% CE) and set B (with 2% CE) in series II did not show a noticeable difference, where >80% of the samples had soil-water contact angles <90°. Water entry value (R2= 0.83–0.92) and the water retention at 150 cm suction (R2= 0.69–0.8) of all the samples increased with increasing soil-water contact angles showing moderate to strong positive linear correlations. However, set A (without 2% CE) and set B (with 2% CE) in series II did not differ noticeably. Water entry value of about 60% the samples was <2.5 cm. Mixing of a small amount (2%) of hydrophobic organic matter with commonly used organic manures slightly increased the water repellency of sample soils, however not up to detrimental levels. It did not generate adverse effects on water entry and increased the water retention. It was clear that intermixing of small quantities of hydrophobic organic manure with organic manures commonly used in Sri Lankan agriculture, would not generate unfavorable impacts on soils.

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 Strength and Water-Repelling Properties of Cement Mortar Mixed with Water Repellents

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5407
Author(s):  
Hyeju Kang ◽  
Sukpyo Kang ◽  
Byoungky Lee
Keyword(s):  
Contact Angle ◽  
Compressive Strength ◽  
Water Contact Angle ◽  
Cement Mortar ◽  
Contact Angles ◽  
Water Repellent ◽  
Water Contact ◽  
Rapid Hardening ◽  
Before And After ◽  
Large Water

In this study, the compressive strength and water contact angle of mortar specimens prepared by mixing two types of water repellent with ordinary Portland cement (OPC) and rapid-hardening cement mortar were measured before and after surface abrasion. In addition, the hydration products and chemical bonding of cement mortar with the repellents were examined using X-ray diffraction (XRD), thermogravimetry-differential thermal analysis (TG-DTA), and Fourier-transform infrared spectroscopy (FT-IR) to evaluate the performance of these cement mortar mixtures as repair materials. We found that the fast-hardening cement mortar mixture containing the oligomer water repellent showed the best performance with a high compressive strength and large water contact angle. With the oligomer water repellent, the rapid-hardening cement mortar mixture showed contact angles of 131° and 126° even after a 2 mm abrasion, thereby confirming that the water repellent secured hydrophobicity through strong bonding with the entire cement mortar as well as its surface. The compressive strengths were found to be 34.5 MPa at 3 h and 54.8 MPa at 28 days, confirming that hydration occurred well despite the addition of water repellent.

Hydrophobization of epoxy nanocomposite surface with 1H,1H,2H,2H-perfluorooctyltrichlorosilane for superhydrophobic properties

Open Physics ◽  
2012 ◽  
Vol 10 (5) ◽  
Author(s):  
Maciej Psarski ◽  
Jacek Marczak ◽  
Grzegorz Celichowski ◽  
Grzegorz Sobieraj ◽  
Konrad Gumowski ◽  
...  
Keyword(s):  
Surface Treatment ◽  
Contact Angles ◽  
Alumina Nanoparticles ◽  
Water Repellent ◽  
Sliding Angle ◽  
Water Contact ◽  
Epoxy Nanocomposite ◽  
Liquid Phases ◽  
Modified Surfaces ◽  
The Hierarchical Structure

AbstractNature inspires the design of synthetic materials with superhydrophobic properties, which can be used for applications ranging from self-cleaning surfaces to microfluidic devices. Their water repellent properties are due to hierarchical (micrometer- and nanometre-scale) surface morphological structures, either made of hydrophobic substances or hydrophobized by appropriate surface treatment. In this work, the efficiency of two surface treatment procedures, with a hydrophobic fluoropolymer, synthesized and deposited from 1H,1H,2H,2H-perfluorooctyltrichlorosilane (PFOTS) is investigated. The procedures involved reactions from the gas and liquid phases of the PFOTS/hexane solutions. The hierarchical structure is created in an epoxy nanocomposite surface, by filling the resin with alumina nanoparticles and micron-sized glass beads and subsequent sandblasting with corundum microparticles. The chemical structure of the deposited fluoropolymer was examined using XPS spectroscopy. The topography of the modified surfaces was characterized using scanning electron microscopy (SEM), and atomic force microscopy (AFM). The hydrophobic properties of the modified surfaces were investigated by water contact and sliding angles measurements. The surfaces exhibited water contact angles of above 150° for both modification procedures, however only the gas phase modification provided the non-sticking behaviour of water droplets (sliding angle of 3°). The discrepancy is attributed to extra surface roughness provided by the latter procedure.

scholarly journals Anti-icing performance of hydrophobic material used for electromechanical drill applied in ice core drilling

2020 ◽  
Vol 66 (258) ◽  
pp. 618-626 ◽  
Author(s):  
Pinlu Cao ◽  
Zhuo Chen ◽  
Hongyu Cao ◽  
Baoyi Chen ◽  
Zhichuan Zheng
Keyword(s):  
Shear Strength ◽  
Ice Core ◽  
Water Repellency ◽  
Contact Angles ◽  
Curved Surface ◽  
Coating Materials ◽  
Water Contact ◽  
Hydrophobic Coating ◽  
Main Challenge ◽  
Ice Adhesion

AbstractUsing an anti-icing coating to prevent ice accretion on the drill surface is a feasible solution to address the drilling difficulties in warm ice. In this study, four types of commercially available hydrophobic coating materials were tested to evaluate their water repellency and anti-icing properties, namely, a mixture of silica and fluorocarbon resin with polytrifluoroethylene, modified Teflon, silica-based emulsion and an acrylic-based copolymer. Their water contact angles are ~107°, 101°, 114° and 95°, respectively. All these hydrophobic coatings can significantly reduce the strength of the ice adhesion within a temperature range of −10 to −30°C on a planar or curved surface. The coating of an acrylic-based copolymer, in particular, can reduce the average tensile strength and the shear strength of the ice adhesion by 87.08 and 97.11% on planar surfaces at −30°C, and by 98.06 and 96.15% on a curved surface, respectively. The main challenge in the practical application of these coatings is their durability. An acrylic-based copolymer coating will lose its water repellency performance after 140 cycles of abrasion. The shear strength of ice adhered on curved surfaces coated with this material will approach that achieved on uncoated surfaces after 11 cycles of icing and de-icing tests.

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