698 PB 306 WETTABILITY AND SURFACE TENSION OF FRUIT SURFACES

Nettability is an important factor to be considered in postharvest treatments such as washing, aqueous dippings, coatings, etc. Pome fruits (ten apple and four pear cultivars) and stone fruits (nectarine and plums) were evaluated for wetting behavior and surface tension at room temperature. Nettability was assessed by measuring contact angles of water. Surface tension was calculated by measuring contact angles of methylene iodide and water or by a series of pure surfactants using Zisman's method. Wetting behavior on apple fruits depended on cultivar, with water contact angles ranging from 75° to 131°. For pear fruits, wetting also depended on cultivar. Calculated surface tensions of pear fruits were in general higher than most apple cultivars tested. In stone fruits, plums presented a high water-repellency with a contact angle of 137°. The wetting of fruit surfaces seems to be governed by the nature of the chemical groups exposed on the surface of the cuticle and also by the surface roughness, as evidenced by tire high values of some contact angles.

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Amphiphobic Nanostructured Coatings for Industrial Applications

Materials ◽

10.3390/ma12050787 ◽

2019 ◽

Vol 12 (5) ◽

pp. 787 ◽

Cited By ~ 5

Author(s):

Federico Veronesi ◽

Giulio Boveri ◽

Mariarosa Raimondo

Keyword(s):

Surface Tension ◽

Contact Angle ◽

Photoelectron Spectroscopy ◽

Contact Angle Hysteresis ◽

Contact Angles ◽

Friction Reduction ◽

Hybrid Coatings ◽

Wetting Behavior ◽

Wide Range ◽

Solid Liquid

The search for surfaces with non-wetting behavior towards water and low-surface tension liquids affects a wide range of industries. Surface wetting is regulated by morphological and chemical features interacting with liquid phases under different ambient conditions. Most of the approaches to the fabrication of liquid-repellent surfaces are inspired by living organisms and require the fabrication of hierarchically organized structures, coupled with low surface energy chemical composition. This paper deals with the design of amphiphobic metals (AM) and alloys by deposition of nano-oxides suspensions in alcoholic or aqueous media, coupled with perfluorinated compounds and optional infused lubricant liquids resulting in, respectively, solid–liquid–air and solid–liquid–liquid working interfaces. Nanostructured organic/inorganic hybrid coatings with contact angles against water above 170°, contact angle with n-hexadecane (surface tension γ = 27 mN/m at 20 °C) in the 140–150° range and contact angle hysteresis lower than 5° have been produced. A full characterization of surface chemistry has been undertaken by X-ray photoelectron spectroscopy (XPS) analyses, while field-emission scanning electron microscope (FE-SEM) observations allowed the estimation of coatings thicknesses (300–400 nm) and their morphological features. The durability of fabricated amphiphobic surfaces was also assessed with a wide range of tests that showed their remarkable resistance to chemically aggressive environments, mechanical stresses and ultraviolet (UV) radiation. Moreover, this work analyzes the behavior of amphiphobic surfaces in terms of anti-soiling, snow-repellent and friction-reduction properties—all originated from their non-wetting behavior. The achieved results make AM materials viable solutions to be applied in different sectors answering several and pressing technical needs.

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Water Shedding Properties of Oil Impregnated Hydrophobic Soils

10.5194/egusphere-egu2020-765 ◽

2020 ◽

Author(s):

Rebecca McCerery ◽

John Woodward ◽

Glen McHale ◽

Kate Winter

Keyword(s):

Soil Water ◽

Silicone Oil ◽

Water Repellency ◽

Contact Angles ◽

Water Infiltration ◽

Natural Soil ◽

Particle Sizes ◽

Soil Water Repellency ◽

Water Contact ◽

Naturally Occurring

<p>Hydrophobic soils and sediments have gained significant interest in soil science due to negatively influencing biomass production and as drivers of landslides and enhanced erosion. Whilst natural and fire-induced soil water repellency have been studied, little work has considered how the sediment-water interaction with naturally occurring hydrophobic sediments might change in the presence of oil. Recent advances in materials physics have shown bio-inspired slippery liquid infused porous surfaces (SLIPS) and lubricant impregnated surfaces (LIS) can produce super slippery surfaces with excellent water shedding properties. Here we apply this new understanding to the physics of soil water repellency and address how the presence of oil, whether from contamination or otherwise, might influence water infiltration. We hypothesise that oil impregnating a hydrophobic soil may create stable oil coatings and/or layers that create soil surfaces resistant to water infiltration and with enhanced run-off of water. Using monolayers of sand, silt and clay particles treated with a commercial hydrophobising agent and silicone oil, we created model (oil-free) hydrophobic and oil impregnated hydrophobic soils. Static water contact angles and droplet sliding angles were used to classify their degree of hydrophobicity and ability to shed water. Our results show that in the absence of oil, model hydrophobic soil surfaces with particle sizes below 63&#956;m are superhydrophobic with water droplet contact angles above 150 degrees. In the presence of oil, we observed a sediment-based SLIP/LI surface on particle sizes below 63&#956;m with water contact angles of 90 degrees and droplet sliding angles of below 5 degrees. We also achieved reduced sliding angles compared to the oil-free surfaces, and a conformal layer of oil on all particle sizes. These results support our hypothesis that SLIPS/LIS may occur in natural soil systems. These results have implications for soil water repellency, oil clean up from soil and for processes occurring in other sedimentary environments caused by both naturally occurring and anthropogenic contamination of oils.</p>

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

Heritage ◽

10.3390/heritage4040150 ◽

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.

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Crosslinked waterborne polyurethane with high waterproof performance

Polymer Chemistry ◽

10.1039/c6py00350h ◽

2016 ◽

Vol 7 (23) ◽

pp. 3913-3922 ◽

Cited By ~ 35

Author(s):

Fangfang Yu ◽

Liwei Cao ◽

Zhaohui Meng ◽

Naibo Lin ◽

Xiang Yang Liu

Keyword(s):

Thermal Properties ◽

Water Absorption ◽

Waterborne Polyurethane ◽

High Water ◽

Contact Angles ◽

Water Contact ◽

Fluorinated Acrylate ◽

Waterborne Polyurethanes

Fluorinated acrylate and siloxane waterborne polyurethanes with crosslinked structure exhibit low water absorption, high water contact angles, and high mechanical/thermal properties.

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

Journal of Hydrology and Hydromechanics ◽

10.1515/johh-2016-0025 ◽

2016 ◽

Vol 64 (2) ◽

pp. 160-166 ◽

Cited By ~ 8

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.

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Supramolecular functionalized polybenzoxazines from azobenzene carboxylic acid/azobenzene pyridine complexes: synthesis, surface properties, and specific interactions

RSC Advances ◽

10.1039/c4ra15107k ◽

2015 ◽

Vol 5 (17) ◽

pp. 12763-12772 ◽

Cited By ~ 24

Author(s):

Mohamed Gamal Mohamed ◽

Chi-Hui Hsiao ◽

Kuo-Chih Hsu ◽

Fang-Hsien Lu ◽

His-Kang Shih ◽

...

Keyword(s):

Carboxylic Acid ◽

Surface Properties ◽

High Water ◽

Contact Angles ◽

Supramolecular Complex ◽

Specific Interactions ◽

Water Contact ◽

Pyridine Complexes

Supramolecular complex of azobenzene carboxylic acid/pyridine functionalized benzoxazine system featured significantly lower curing temperatures and maintain high water contact angles.

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

Journal of Glaciology ◽

10.1017/jog.2020.33 ◽

2020 ◽

Vol 66 (258) ◽

pp. 618-626 ◽

Cited By ~ 1

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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Effect of Spontaneous and Water-Based Passivation on Components and Parameters of Ti6Al4V (ELI Grade) Surface Tension and Its Wettability by an Aqueous Solution of Sucrose Ester Surfactants

Molecules ◽

10.3390/molecules27010179 ◽

2021 ◽

Vol 27 (1) ◽

pp. 179

Author(s):

Joanna Krawczyk ◽

Amparo María Gallardo-Moreno ◽

María Luisa González-Martín

Keyword(s):

Surface Tension ◽

Aqueous Solutions ◽

Surface Treatment ◽

Water Environment ◽

Surface Preparation ◽

Contact Angles ◽

Sucrose Ester ◽

Water Interface ◽

Water Contact ◽

Solid Water

Solid wettability is especially important for biomaterials and implants in the context of microbial adhesion to their surfaces. This adhesion can be inhibited by changes in biomaterial surface roughness and/or its hydrophilic–hydrophobic balance. The surface hydrophilic–hydrophobic balance can be changed by the specifics of the surface treatment (proper conditions of surface preparation) or adsorption of different substances. From the practical point of view, in systems that include biomaterials and implants, the adsorption of compounds characterized by bacteriostatic or bactericidal properties is especially desirable. Substances that are able to change the surface properties of a given solid as a result of their adsorption and possess at least bacteriostatic properties include sucrose ester surfactants. Thus, in our studies the analysis of a specific surface treatment effect (proper passivation conditions) on a biomaterial alloy’s (Ti6Al4V ELI, Grade 23) properties was performed based on measurements of the contact angles of water, formamide and diiodomethane. In addition, the changes in the studied solid surface’s properties resulting from the sucrose monodecanoate (SMD) and sucrose monolaurate (SML) molecules’ adsorption at the solid–water interface were also analyzed. For the analysis, the values of the contact angles of aqueous solutions of SMD and SML were measured at 293 K, and the surface tensions of the aqueous solutions of studied surfactants measured earlier were tested. From the above-mentioned tests, it was found that water environment significantly influences the components and parameters of Ti6Al4V ELI’s surface tension. It also occurred that the addition of both SMD and SML to water (separately) caused a drop in the water contact angle on Ti6Al4V ELI’s surface. However, the sucrose monolaurate surfactant is characterized by a slightly better tendency towards adsorption at the solid–water interface in the studied system compared to sucrose monodecanoate. Additionally, based on the components and parameters of Ti6Al4V ELI’s surface tension calculated from the proper values of components and parameters of model liquids, it was possible to predict the wettability of Ti6Al4V ELI using the aqueous solutions of SMD and SML at various concentrations in the solution.

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Superhydrophobic paper coating containing nonconventional clay

TAPPI Journal ◽

10.32964/tj911.33 ◽

2010 ◽

Vol 9 (11) ◽

pp. 33-40 ◽

Cited By ~ 5

Author(s):

BEHUDIN (BEKO) MESIC ◽

CHRISTIAN KUGGE ◽

LARS JÄRNSTRÖM

Keyword(s):

Water Absorption ◽

Cross Sections ◽

Transmission Rate ◽

High Water ◽

Contact Angles ◽

Water Contact ◽

Barrier Performance ◽

Superhydrophobic Paper ◽

Hydrophobic Clay ◽

Scanning Electron

Hydrophobic clay fillers have not been widely used in dispersion coatings for linerboard because of the difficulty of dispersing them in water. This work investigated whether hydrophobic clay can be used as filler in barrier dispersion coatings. Hydrophobic clay was compared with conventional clay in terms of coating consolidation, structure, wetting, and barrier performance. All coatings were applied to linerboard sheets made using a laboratory dynamic sheet former. The coated linerboards were examined using scanning electron microscopy and Raman spectroscopy, and were characterized with respect to water absorption, vapor transmission rate, and contact angles. The results show that a coating containing hydrophobic clay provides a superhydrophobic character to paper; i.e., a high water contact angle (150°) and relatively low water absorption. Raman mapping of cross-sections revealed that the latex distribution is uniform in the presence of either conventional clay or hydrophobic clay, and that the distribution of hydrophobic clay tends to be more uniform than conventional clay, which might reflect good mixing and consolidation of hydrophobic clay.

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Stable super-hydrophobic and comfort PDMS-coated polyester fabric

e-Polymers ◽

10.1515/epoly-2021-0059 ◽

2021 ◽

Vol 21 (1) ◽

pp. 654-661

Author(s):

Liyun Xu ◽

Kaifang Xie ◽

Yuegang Liu ◽

Chengjiao Zhang

Keyword(s):

Water Repellency ◽

High Water ◽

Polyester Fabric ◽

Small Scale ◽

Water Contact ◽

Pdms Film ◽

Practical Applications ◽

Pet Fabric ◽

Cost Efficient ◽

Poly Ethylene

Abstract Super-hydrophobic fabrics have shown great potential during the last decade owing to their novel functions and enormous potential for diver’s applications. Surface textures and low surface energy coatings are the keys to high water repellency. However, the toxicity of nanomaterials, long perfluorinated side-chain polymers, and the fragile of micro/nano-texture lead to the super-hydrophobic surfaces are confined to small-scale uses. Thus, in this article, a stable polydimethylsiloxane (PDMS)-coated super-hydrophobic poly(ethylene terephthalate) (PET) fabric (PDMS-g-PET) is manufactured via dip-plasma crosslinking without changing the wearing comfort. Benefiting from the special wrinkled structure of PDMS film, the coating is durable enough against physical abrasion and repeated washing damage, which is suffered from 100 cycles of washing or 500 abrasion cycles, and the water contact angle is still above 150°. This study promotes the way for the development of environmentally friendly, safe, and cost-efficient for designing durable superhydrophobic coatings for various practical applications.

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