Contact Angle Of Distilled Water Research Articles

An Experimental Study on the Influence of the Fractal Characteristics of X80 Steel Surface Morphology on Water Ring Stability

The surface morphology of X80 steel with hydrophilic underwater oleophobic characteristic is described greater comprehensively and quantitatively in this work by combining fractal dimension and multifractal. X80 steel with hydrophilic underwater oleophobic surface characteristics was constructed using a chemical etching method. Then, with the aid of three wettability parameters—contact angle, rolling angle, and adhesion work—this study investigated the relationship between the surface fractal dimension of X80 and the stability of the water ring in the core annular flow. The results showed that: (1) the fractal dimension of X80 steel specimens increased first and then decreased with the increase of reaction time. Besides that, the value of it was greater than 2, indicating that the surface had obvious fractal characteristics. The spectral difference, Δf(α), and the spectral width, Δα, supplemented the description of the X80 steel surface morphology, which was consistent with the scanning electron microscope results. (2) When the maximum fractal dimension was 2.0808, the minimum contact angle of distilled water on its surface was 50.2°, and the maximum contact angle of underwater oil droplets was 166.4°. The larger the fractal dimension of X80 steel with hydrophilic underwater oleophobic properties, the more hydrophilic and underwater oleophobic it is. This illustrated that there was a strong binding force between the water and the X80 steel pipe wall, and hence the quality and efficiency of the core annular flow was improved, which was more conducive to the promotion of this technology in the field of heavy oil transportation.

Hydrophobicity of the biofunctionalized scaffolds for bone tissue engineering application in dentistry

Objective: This study aimed to characterize the hydrophobicity of the functionalized scaffolds for bone tissue engineering applications in Dentistry. Materials and Methods: This experimental study was conducted in the Tissue Engineering Laboratory of The University of Sheffield. The scaffolds were polycaprolactone (PCL) and functionalized using heparin, divided into five groups of prepared electrospun scaffolds. i.e., 1) Fully coated heparin, 2) Random drops of heparin, 3) Organized drops of heparin, 4) Stamping-micropockets with heparin, 5) PCL scaffold only (Control). Hydrophobicity was characterized by measuring the contact angle of distilled water drops on the scaffolds. One-way ANOVA was used as a data analysis test, with p<0.05. Result: The mean contact angle of each group was 63.33, 63.83, 63.33, 73.00, and 64.58, respectively. There was no group of scaffolds categorized as hydrophobics and no statistically significant difference among and within groups. Conclusion: The functionalized scaffolds were mostly un-hydrophobic, being a deliberation of their biocompatibility and role in bone tissue engineering application in dentistry.

Evaluating wettability of vessels in poplar by Micro-CT imaging

Abstract The wettability of wood affects some natural phenomena and applications in industry, such as the ascent of sap in the plant stem, wood drying, and impregnation processes for wood modification. Wettability is generally evaluated by measuring the contact angle using techniques such as the sessile drop method and the Wilhelmy method. However, these methods are not applicable to phenomena at the micro-scale such as liquid transport in hardwood vessels. In this study, micro-CT was used to measure the contact angle of liquid in a single wood vessel directly at the submicron scale. The wettability of a wood vessel was analyzed using contact angles of distilled water and diiodomethane. Conventional contact angles of the wood surface were measured using a fixed drop technique. The average contact angle in a vessel determined by the direct CT observation was significantly smaller than that on the wood surface measured by the sessile drop technique. This discrepancy is attributable to the higher total surface energy of the vessel compared to the free energy of a flat surface. The difference in surface energy is due to different chemical composition distributions in various cell wall layers, roughness and surface topography between the wood surface and vessels, and moisture state.

Evaluation of color changes, wettability, and moisture sorption of heat-treated blue-stained radiata pine lumber

To improve the color and surface properties of blue-stained radiata pine, heat treatment was carried out at different temperatures and times. The color change, wettability, and dynamic moisture sorption of the wood were investigated. The results showed that, as the treatment temperature and duration time increased, the surface brightness of specimens gradually decreased, and the surface color became more reddish and blueish. In addition, the contact angle of distilled water at 0 s and 18 s gradually increased as the treatment temperature and time increased, which indicated a decrease in the surface wettability. The color of the blue-stained wood became more uniform with reduced surface wettability and hygroscopicity but increased sorption hysteresis after the treatment.

Effect of Sanding Processes on the Surface Properties of Modified Poplar Coated by Primer Compared with Mahogany

The surface roughness, static and dynamic liquid wettability of modified poplar wood were measured by different surface treatment of brushing primer and sanding. With the increase of the number of grinding paper, the depth parameters Ra, Ry, Rz and Rp of surface roughness of modified poplar decreased, and the density parameter Sm (the average spacing of micro unevenness of contour) decreased at first and then increased. With the increase of number of the grinding paper, the contact angle of water and glycerol for modified poplar wood decreased at first and then increased. After the modified poplar wood was brushed with the primer and sanded with 240# sandpaper, the density parameter Sm was 0.307, the equilibrium contact angle of distilled water was 34.88, and the equilibrium contact angle of glycerin was 36.46, all of which were the lowest number. At this time, the surface roughness was improved, and the modified poplar has the good wettability that is greater than the mahogany wood wettability. Compared with mahogany, the rough depth parameters of the modified poplar are smaller to those of mahogany, but the Sm of modified poplar wood is greater than that of the mahogany. After the same surface pretreatment, the wetting speed of glycerol on the surface of mahogany is higher than that of the modified poplar.

The influence of corrosion of inorganic-organic films on their surface properties

The work deals with the influence of water corrosion on the surface properties of inorganic-organic SiO2 films, which were prepared from the sols in “tetraethoxysilane-isopropyl alcohol-water-nitric acid-triethoxy(octyl)silane” system. The atomic force microscopy and sessile drop technique was used on the characterization of surface properties. The morphology, rms-roughness, adhesion force and stiffness of prepared films were evaluated. Surface free energy and its polar and dispersion component were calculated by Owens-Wendt method using contact angles of distilled water and diiodomethane. The influence of corrosion on all of the studied properties of films was significant in the case of films prepared from sol with molar ratio of x(H2O) : x(SiO2) = 2.

Separation of Water-Oil Emulsion Using Polyethersulfone Membranes Treated with High-Frequency Low-Temperature Plasma

A study of the water-oil emulsion separation by polyethersulfone membranes with a mass of cutoff particles 10 kDa was carried out. The membranes were treated with a low-temperature highfrequency capacitive reduced pressure plasma in an argon and nitrogen medium (70:30) at a voltage of Ua = 1.5–5.5 kV and processing time τ = 1.5–7 minutes. Round flatfilter elements with a diameter of 47 mm were used in the capacity of membranes. The emulsion with a concentration of 3% (by volume) was prepared on the basis of Devon oil from the Tumutukskoye oil field and distilled water and was stabilized by the Kosintol-242 surfactant. The experiments were carried out on a laboratory ultra filtration separation unit. Based on the results of the studies, an increase in the separation productivity of the water-oil emulsions after plasma treatment of the membranes is shown; an increase in the studied process efficiency from 95.1 to 98.4% with the exposure by plasma at U = 3.5 kV and τ = 7 min is noted. Using electron microscopy, sedentary droplet, and IR spectroscopy methods, we have revealed an increase in the surface roughness of the membranes after plasma treatment with nitrogen argon, as a result of which the contact angle of distilled water decreased from 75.3° to 65.3°, which indicates an increase in hydrophilicity and, respectively, water absorption, and in addition, the formation of oxygen-containing functional groups and the hydrogen bonds in the surface structure of the polymer polyethersulfone membrane.

Surface properties of plasma electrolytic oxidation coatings on Ti-alloy in phosphate–based electrolytes with the addition of sodium metasilicate

We have investigated effects of the sodium metasilicate addition into phosphate-based electrolytes on the surface properties of plasma electrolytic oxidation (PEO)-coated layers on Ti-6Al-4V. The surface properties of the PEO-coated layers have been characterized by using field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy, and contact angle measurements. The study shows that the addition of sodium metasilicate in the phosphate-based electrolytes leads to the roughening surface and the change in the surface composition the PEO-coated layers. In addition, the contact angle of distilled water on the surface of the PEO-coated layers with the sodium metasilicate additive in electrolytes is reduced, resulting in higher surface energy.

Effects of non-thermal atmospheric plasma treatment on dentin wetting and surface free energy for application of universal adhesives

The study aims to evaluate the effects of non-thermal atmospheric plasma (NTAP) treatments on dentin wetting and surface free energy (SFE) and compare the effects of NTAP treatment, etch-and-rinse, and self-etch protocols for application of universal adhesives. Mid-coronal dentin of intact third molars was used to measure contact angles of distilled water, ethylene-glycol, and diiodomethane and calculate SFE following different NTAP preset treatments (feeding gas consisting of pure He, He + 1% O2, He + 1.5% O2), power input (1 or 3W), and tip-to-surface distance (2, 4, or 8mm). Contact angles of reference liquids and SFE of dentin following He + 1.5% O2 at 3-W and 4-mm treatment was compared to phosphoric acid etching. Contact angles of Single Bond Universal (SBU; 3M ESPE) and Clearfil Universal Bond (CUB; Kuraray Noritake) were measured following NTAP, etch-and-rinse, and self-etch protocols. NTAP significantly reduced contact angles of reference liquids and increased dentin SFE compared to untreated dentin (p< 0.05). O2 intensified the effect of He NTAP (p< 0.05). NTAP and phosphoric acid increased dentin polarity and Lewis base surface characteristics. Phosphoric acid increased contact angles of adhesives compared to the self-etch protocol (p< 0.05). NTAP resulted in lower adhesive contact angles than phosphoric acid, the difference being statistically significant for CUB (p< 0.05). Compared to the self-etch protocol, NTAP slightly reduced CUB contact angle but not that of SBU (p> 0.05). He NTAP with and without O2 increased dentin wetting and SFE, surpassing the effect of phosphoric acid and lowering adhesive contact angles. NTAP produced no apparent micro-morphological changes on dentin surface comparable to acid etching. NTAP treatment of dentin prior to adhesive application increases dentin wetting and surface free energy facilitating better adhesive distribution on dentin surface compared to phosphoric acid etching and similar to the "self-etch" application protocol.

Ultrafiltration of Oil-in-Water Emulsions with a Dynamic Nylon–Polystyrene Membrane

Dynamic nylon–polystyrene membranes with polystyrene contents of 2.6 and 4.1 wt % have been obtained by applying polystyrene with a particle size of 142–452 nm onto the surface of a nylon membrane with a pore size of 0.45 μm. The deposition of polystyrene onto the surface of the nylon membrane was indirectly confirmed by Fourier-transform IR spectroscopy and probe microscopy. The contact angle of distilled water on the membrane has been found to increase from 44.5° to 106.2° as a result of the deposition of polystyrene particles onto the surface of the initial membrane. The specific productivity of the initial and modified membranes with respect to distilled water and a water–oil emulsion was determined. It has been found that the membrane modification leads to an increase in the degree of removal of petroleum products from an oil-in-water emulsion by 62%; the size of particles separated by the membrane after modification decreased from 450 to 151 nm. It has also been revealed that the specific productivity of the nylon–polystyrene membrane and the original nylon membrane is restored to 98 and 90% of the initial values, respectively, by regeneration.

Isotherm analysis of the solution-phase uptake of chlorotrimethyl silane on a photosensitive glass

We report on analysis of the uptake of chlorotrimethylsilane (CTMS) on a photosensitive glass substrate. Contact angles of distilled water (DI) are measured on substrates immersed over a range of concentrations of CTMS in acetonitrile (ACN) for different immersion times. Contact angles are also measured for coatings stored in anhydrous ACN and ambient air. Samples are characterized with x-ray photoelectron spectroscopy and atomic force microscopy. Characterization supports a patchy layer for the glass chemistry and coverage of CTMS. Contact angles are converted to coverage accordingly. Different isotherms are subsequently tested to fit the coverage data. A modified Freundlich isotherm fcp=1−exp(−(Kco+Kctt)C1/n) is found best, where fcp is fractional coverage, C is solution concentration, t is time, and Kco, Kct, and n are fitting constants. A weighted, chi-squared minimization method is used to fit coverage versus time and concentration comprehensively. The results support a two-step reaction of CTMS depositing in to a patchy monolayer, with best fit values as Kco=0.11832±0.0062 (mg/mL)1/2 and Kct=0.0279±0.0011 (mg/mL)1/2 min−1 for n=2. In summary, these studies provide an optimal protocol to silanate a photosensitive glass and demonstrate the stability of the CTMS coating in ACN, with a focus on applications to functionalize micro-fluidic channels.

Contact angle as function of surface roughness of different wood species

In this study values of contact angle of distilled water on differently rough beech (Fagus sylvatica L.), birch (Betula pendula), sessile oak (Quercus petraea) and spruce (Picea abies) surfaces have been investigated in order to find the trend of their relation. Samples have been sanded with sandpaper of 13 different grit sizes: 60, 80, 100, 120, 150, 180, 220, 240, 280, 320, 400, 500 and 600. After sanding, contact angle measurements have been performed on the freshly prepared wood surfaces using sessile drop method. Exponential relation has been found between the contact angle of differently rough spruce, beech, birch and sessile oak surfaces and the grit size of the sanding paper. Based on the upper relation, three well distinguishable portions of surface roughness have been identified with decreasing, stagnating and increasing values of the contact angle.

Changes in Surface Properties of Heat-Treated Phyllostachys pubescens Bamboo

The wetting phenomena and surface energetic behavior in heat-treated bamboo were studied. The bamboo specimens were heat-treated at temperatures of 100, 140, and 180 °C for 4 h, and an untreated sample served as a control. The sessile drop technique was used to estimate the surface contact angles of the control and heat-treated bamboo samples. The contact angle data were then used to determine the surface free energies using the Lifshitz-van der Waals/acid-based approach. The results revealed that the heat treatment process affects surface wettability. Heat treatment at 100 to 180 °C increased the contact angle of distilled water and formamide, but heat treatment did not cause any increase in the contact angle of diiodomethane. The hydrophobic characteristics of the bamboo surfaces also increased under heat treatment, and the surface free energy and the polarity of the bamboo decreased. Surface analysis by XPS of the samples heat-treated at 180 °C showed a decreased O/C ratio and increased C1 peak, indicating that more lignin and extractives were situated on the bamboo surface. Changes in wettability can greatly impact the use of the material, particularly with respect to the adhesion of paints and coatings.

The Relation Between (meth)Fluoroacrylate Copolymer Structure and Reservoir Rock Wettability

With the unique structure of fluorocarbon chain, (meth)fluoroacrylate copolymer could dramatically reduce the rock surface free energy and transfer the wettability into amphiphobic; thus, the liquid liquidity and productivity of the reservoir could be enhanced. The relation between copolymer molecular structure and the wettability reversal degree are discussed by measuring the contact angle, surface free energy, and the scanning electron microscopy. The length and structure of a fluorocarbon chain has a great effect on the wettability reversal, while the methyl in the main chain contributes little. The contact angle of distilled water and hexadecane on the natural core surface maximum is up to 123.5 and 60.0°, respectively, after being treated by the (meth)fluoroacrylate copolymer, and the surface free energy is reduced to 8.21719 mJ/m2.

Characterization of a Low Shrinkage Dental Composite Containing Bismethylene Spiroorthocarbonate Expanding Monomer

In this study, a novel dental composite based on the unsaturated bismethylene spiroorthocarbonate expanding monomer 3,9-dimethylene-1,3,5,7-tetraoxa-spiro[5,5]undecane (BMSOC) and bisphenol-S-bis(3-meth acrylate-2-hydroxypropyl)ether (BisS-GMA) was prepared. CQ (camphorquinone) of 1 wt % and DMAEMA (2-(dimethylamino)ethyl methacrylate) of 2 wt % were used in a photoinitiation system to initiate the copolymerization of the matrix resins. Distilled water contact angle measurements were performed for the wettability measurement. Degree of conversion, volumetric shrinkage, contraction stress and compressive strength were measured using Fourier Transformation Infrared-FTIR spectroscopy, the AccuVol and a universal testing machine, respectively. Within the limitations of this study, it can be concluded that the resin composites modified by bismethylene spiroorthocarbonate and BisS-GMA showed a low volumetric shrinkage at 1.25% and a higher contact angle. The lower contraction stress, higher degree of conversion and compressive strength of the novel dental composites were also observed.

Cast Natural Rubber Films Comprising Triethyl Citrate

The various triethyl citrate-loaded natural rubber (NR) films were prepared by casting technique employing dichloromethane (DCM) as solvent. The wettability, mechanical properties and topology of prepared dry films were determined. The contact angle of distilled water onto the cast films was measured using the goniometer. Triethyl citrate-loaded NR films exhibited the continuous porous structure. The presence of triethyl citrate in NR films promoted wettability and surface free energy whereas the tensile strength decreased. The unique porous topography of triethyl citrate-loaded NR film exhibited the potential for applying this material as the scaffold or controlled drug delivery devices in the future.

Tribological characteristics of novel branched perfluoropolyether lubricant films in hard disk drives

In this study, the basic tribological characteristics of novel branched perfluoropolyether (PFPE) lubricant films such as TA-30 and QA-40 were examined. Their surface free energy characteristics and adhesive and friction forces were investigated using an atomic force microscope. The interactions between the lubricant molecules and the water molecules were also examined by monitoring the changes in the contact angle of distilled water on the test lubricant films. The interactive forces such as the adhesive and friction forces of a film that is approximately one monolayer thick were found to be strongly dependent on the conformation of the lubricant molecules on diamond-like carbon thin films. In addition, the TA-30 and QA-40 lubricant molecules appeared to interact with the water molecules more actively than conventional Ztetraol2000 molecules. These results afforded fundamental insight into the tribological performance of novel branched PFPE lubricants in the head-disk interface.

Preparation and micro-tribological property of hydrophilic self-assembled monolayer on single crystal silicon surface

A kind of nano-film was prepared by self-assembling 6-(3-triethoxysilylpropylamino)-1,3,5-triazine-2,4-dithiol monosodium (TES) on the surface of single crystal silicon with hydroxylated pretreatment. The features of the self-assembled monolayer (SAM) were characterized by contact angle meter, spectroscopic ellipsometer, atomic force microscope, X-ray photoelectron spectroscopy and infrared spectroscopy. The experimental results show that the contact angle of distilled water for self-assembled monolayer (SAM) was 35.5° and the film thickness was 3.7nm, and orderly directional nano-clusters were covered on the surface by observation of the topography. Besides, the friction and wear properties of the SAM were investigated under micro-load by universal micro-tribotester. Compared with the substrate, the friction coefficient of the SAM was effectively reduced from 0.494 to 0.102, which was due to the lubricant of the SAM coating. Meanwhile, the film was not destroyed until 130 cycle times of reciprocating gliding under load of 10g. The friction and wear tests show this hydrophilic SAM also has a lubrication effect on the surface while other SAMs often exhibited hydrophobic properties. It is expected that the hydrophilic SAM will be applied in micro electromechanical systems as the solid lubricant coatings.

Preparation and Properties of Polymeric Nano Composite Filmon Surface of Sintered NdFeB Permanent Magnet

A nanofilm(TES-SAMs) was prepared by self-assembly of 6-(3-triethoxysilylpropylamino)-1,3,5-triazine-2,4-dithiol monosodium(TES) on a sintered NdFeB surface.A nano composite film(TES-ATP) was then prepared on the TES-SAMs surface by a self-developed polymer plating technique using 6-(N-allyl-1,1,2,2-tetrahydroperfluorodecylamino)-1,3,5-triazine-2,4-dithiol monosodium(ATP).The surface of the TES-SAMs and TES-ATP were characterized by X-ray photoelectron spectroscopy(XPS),Fourier transform infrared(FTIR) spectroscopy,spectroscopic ellipsometry,atomic force microscopy(AFM),and contact angle measurements.A UMT-2 tribometer was used to investigate their micro-tribological properties.The experimental results showed that the thicknesses of TES-SAMs and TES-ATP were 5.08 and 29.78 nm,respectively.The surface free energy of TES-ATP and TES-SAMs decreased from 73.13 mJ·m-2 for the substrate to 10.19 and 63.39 mJ·m-2,respectively.The contact angle of distilled water on TES-ATP was 123.5°,indicating transformation from a hydrophilic surface to a hydrophobic one.The friction coefficient was effectively reduced from 0.71 for the substrate to 0.22 for TES-SAMs and 0.12 for TES-ATP.In addition,the TES-ATP composite film possessed excellent anti-wear ability.Thus,the present TES-ATP composite film provides a novel approach to solving tribological issues in micro-electro-mechaanical system(MEMS).

Enhancing the Surface Wettability of Poly(Ethylene Terephthalate) Film by Atmospheric Pressure Plasma Treatment with Ar and N2Gas Mixture

In this work, the specific influences of atmospheric pressure plasma (APP) treatment on the surface modifications of poly(ethylene terephthalate) (PET) polymeric film have been explored. The APP was generated using dielectric barrier discharge in the ambient of Ar and N2gas mixture. Experimental results of the surface properties are presented for the PET film before and after the APP treatment. The exposure of PET films to APP leads to the roughening surface. Also, the APP-induced modifications are associated with incorporation of polar oxygen and nitrogen containing groups on the PET surface. Due to the changes of chemical composition and topology on the surface by the APP treatment, the contact angle of distilled water on the surface becomes smaller, resulting in higher surface wettability.