scholarly journals Comparative analysis of inactivated wood surfaces

Holzforschung ◽  
2004 ◽  
Vol 58 (1) ◽  
pp. 22-31 ◽  
Author(s):  
M. Šernek ◽  
F. A. Kamke ◽  
W. G. Glasser
Keyword(s):  
Contact Angle ◽  
High Temperature ◽  
Wood Species ◽  
Sessile Drop ◽  
Surface Composition ◽  
Contact Angles ◽  
Southern Pine ◽  
Hydrogen Atoms ◽  
Yellow Poplar ◽  
Wood Surfaces

Abstract The surface inactivation of two wood species, yellow poplar (Liriodendron tulipifera) and southern pine (Pinus taeda), was studied following high temperature drying. Surface analysis involved X-ray photoelectron spectroscopy, sessile drop wettability and fracture mechanics of the adhesively-jointed surfaces. The results showed that wood drying at high temperature (i.e., >160 to 180 °C) caused modifications in surface composition. The oxygen to carbon ratio (O/C) decreased and the ratio of carbon atoms bonded to other carbon or to hydrogen atoms vis-à-vis carbons bonded to oxygen atoms (i.e., the C1/C2 ratio) increased with drying temperature. In addition, the contact angle increased with the temperature of exposure, but decreased with time. A dependence on wood species was evident: southern pine surfaces always exhibited higher contact angles than yellow poplar. Also, the rate of contact angle decline with time, dθ/dt, was found to vary with surface composition: this rate corresponded to O/C ratio-changes, especially in the case of southern pine. Southern pine was most susceptible to inactivation particularly when bonded with PF adhesive. Yellow poplar surfaces did not show significant inactivation when exposed to drying temperatures below ca. 180 °C. The results are explained by a relative enrichment of wood surfaces with non-polar substances, hydrophobic extractives and volatile organic compounds that 'become visually evident during the drying process at temperatures above ca. 160 °C. Little change was observed if drying temperatures remained below 150 °C.

Comparative Study of Surface Energies of Native Oxides of Si(100) and Si(111) via Three Liquid Contact Angle Analysis

MRS Advances ◽  
2018 ◽  
Vol 3 (57-58) ◽  
pp. 3379-3390 ◽  
Author(s):  
Saaketh R. Narayan ◽  
Jack M. Day ◽  
Harshini L. Thinakaran ◽  
Nicole Herbots ◽  
Michelle E. Bertram ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Energy ◽  
Sessile Drop ◽  
Surface Composition ◽  
Ion Beam ◽  
Contact Angles ◽  
Van Der Waals Interactions ◽  
Native Oxides ◽  
Relative Errors ◽  
Contact Angle Analysis

ABSTRACTThe effects of crystal orientation and doping on the surface energy, γT, of native oxides of Si(100) and Si(111) are measured via Three Liquid Contact Angle Analysis (3LCAA) to extract γT, while Ion Beam Analysis (IBA) is used to detect Oxygen. During 3LCAA, contact angles for three liquids are measured with photographs via the “Drop and Reflection Operative Program (DROP™). DROP™ removes subjectivity in image analysis, and yields reproducible contact angles within < ±1°. Unlike to the Sessile Drop Method, DROP can yield relative errors < 3% on sets of 20-30 drops. Native oxides on 5 x 1013 B/cm3 p- doped Si(100) wafers, as received in sealed, 25 wafer teflon boats continuously stored in Class 100/ISO 5 conditions at 24.5°C in 25% controlled humidity, are found to be hydrophilic. Their γT, 52.5 ± 1.5 mJ/m2, is reproducible between four boats from three sources, and 9% greater than γT of native oxides on n- doped Si(111), which averages 48.1 ± 1.6 mJ/m2 on four 4” Si(111) wafers. IBA combining 16O nuclear resonance with channeling detects 30% more oxygen on native oxides of Si(111) than Si(100). While γT should increase on thinner, more defective oxides, Lifshitz-Van der Waals interactions γLW on native oxides of Si(100) remain at 36 ± 0.4 mJ/m2, equal to γLW on Si(111), 36 ± 0.6 mJ/m2, since γLW arises from the same SiO2 molecules. Native oxides on 4.5 x 1018 B/cm3 p+ doped Si(100) yield a γT of 39 ± 1 mJ/m2, as they are thicker per IBA. In summary, 3LCAA and IBA can detect reproducibly and accurately, within a few %, changes in the surface energy of native oxides due to thickness and surface composition arising from doping or crystal structure, if conducted in well controlled clean room conditions for measurements and storage.

scholarly journals Influence of moisture content on the contact angle and surface tension measured on birch wood surfaces

2021 ◽  
Author(s):  
Rami Benkreif ◽  
Fatima Zohra Brahmia ◽  
Csilla Csiha
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Moisture Content ◽  
Solid Wood ◽  
Contact Angles ◽  
Surface Moisture ◽  
Wood Coatings ◽  
The Relationship ◽  
Wood Surfaces

AbstractSurface tension of solid wood surfaces affects the wettability and thus the adhesion of various adhesives and wood coatings. By measuring the contact angle of the wood, the surface tension can be calculated based on the Young-Dupré equation. Several publications have reported on contact angle measured with different test liquids, under different conditions. Results can only be compared if the test conditions are similar. While the roles of the drop volume, image shooting time etc., are widely recognized, the role of the wood surface moisture content (MC) is not evaluated in detail. In this study, the effect of wood moisture content on contact angle values, measured with distilled water and diiodomethane, on sanded birch (Betula pendula) surfaces was investigated, in order to find the relationship between them. With increasing MC from approximately 6% to 30%, increasing contact angle (decreasing surface tension) values were measured according to a logarithmic function. The function makes possible the calculation of contact angles that correspond to different MCs.

Comparative studies of nitrogen plasma and argon plasma treatment on the strength of PBO fibre reinforced high-temperature resistant thermoplastic composite

2021 ◽  
pp. 095400832098729
Author(s):  
K Sudheendra ◽  
Jennifer Vinodhini ◽  
M Govindaraju ◽  
Shantanu Bhowmik
Keyword(s):  
Contact Angle ◽  
High Temperature ◽  
Plasma Treatment ◽  
Sessile Drop ◽  
Dynamic Contact Angle ◽  
Argon Plasma ◽  
Film Surface ◽  
Fibre Surface ◽  
Nitrogen Plasma ◽  
Thermoplastic Composite

The study involves the processing of a novel poly [1, 4-phenylene-cis-benzobisoxazole] (PBO) fibre reinforced high-temperature thermoplastic composite with polyaryletherketone (PAEK) as the matrix. The PBO fibre and the PAEK film surface was modified using the method of argon and nitrogen plasma treatment. The investigation primarily focuses on evaluating the tensile properties of the fabricated laminates and correlating it with the effect of plasma treatment, surface characteristics, and its fracture surface. A 5% decrease in tensile strength was observed post argon plasma treatment while a 27% increase in strength was observed post nitrogen plasma treatment. The morphology of the failure surface was investigated by scanning electron microscopy and an interfacial failure was observed. Furthermore, the effect of plasma on the wettability of PBO fibres and PAEK film surface was confirmed by the Dynamic Contact Angle analysis and sessile drop method respectively. FTIR spectral analysis was done to investigate the effect of plasma treatment on the chemical structure on the surface. The results of the wettability study showed that the argon plasma treatment of the fibre surface increased its hydrophobicity while nitrogen plasma treatment resulted in the reduction of contact angle.

WETTING OF ROUGH SURFACES

2004 ◽  
Vol 11 (01) ◽  
pp. 7-13 ◽  
Author(s):  
XINPING ZHANG ◽  
SIRONG YU ◽  
ZHENMING HE ◽  
YAOXIN MIAO
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Sessile Drop ◽  
Test Sample ◽  
Contact Angles ◽  
Sessile Drop Method ◽  
Equilibrium Contact Angle ◽  
Roughness Surface ◽  
Solid Substrates ◽  
Effect Of Surface

This paper focuses on effects of roughness on wettability. According to Wenzel's equation, the transition of theoretical wetting contact angles is 90°, whereas many experimental results have indicated that such a transition takes place at contact angles smaller than 90°. A new model of wetting on roughness surface is established in this paper. The model indicates that the influencing factors of wetting on roughness surface include not only equilibrium contact angle θ0 and surface roughness, but also the system of liquids and solid substrates. There is a corresponding transition angle for every surface roughness, and the transition angle is lower than 90°. Surface roughness is propitious to improve the contact angle only when θ0 is lower than the transition angle. The effect of surface roughness on the contact angle increases with the increase of rE. To engineer the surface with different roughnesses, a Ti test sample is polished with sandpaper with abrasive number 350, 500, 1000 and 2000; the contact angles of water on Ti are measured by the sessile drop method. The results of the theoretical analysis agree with experimental ones.

scholarly journals Effect of Direct Current on Solid-Liquid Interfacial Tension and Wetting Behavior of Ga–In–Sn Alloy Melt on Cu Substrate

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Limin Zhang ◽  
Ning Li ◽  
Hui Xing ◽  
Rong Zhang ◽  
Kaikai Song
Keyword(s):  
Contact Angle ◽  
Interfacial Tension ◽  
Direct Current ◽  
Sessile Drop ◽  
Contact Angles ◽  
Current Intensity ◽  
Solute Diffusion ◽  
Wetting Behavior ◽  
Cu Substrate ◽  
Solid Liquid

The effect of direct current (DC) on the wetting behavior of Cu substrate by liquid Ga–25In–13Sn alloy at room temperature is investigated using a sessile drop method. It is found that there is a critical value for current intensity, below which the decrease of contact angle with increasing current intensity is approximately linear and above which contact angle tends to a stable value from drop shape. Current polarity is a negligible factor in the observed trend. Additionally, the observed change in contact angles is translated into the corresponding change in solid-liquid interfacial tension using the equation of state for liquid interfacial tensions. The solid-liquid interfacial tension decreases under DC. DC-induced promotion of solute diffusion coefficient is likely to play an important role in determining the wettability and solid-liquid interfacial tension under DC.

Contact Angle of Water Droplets in a High-Temperature, High-Pressure Environment

2004 ◽  
Author(s):  
Tsukasa Hayashi ◽  
Tatsuya Hazuku ◽  
Tomoji Takamasa ◽  
Kenrou Takamori
Keyword(s):  
Contact Angle ◽  
High Pressure ◽  
High Temperature ◽  
Contact Angles ◽  
Surface Wettability ◽  
Water Droplets ◽  
Straight Line ◽  
Angle Condition ◽  
High Pressure Environment ◽  
High Temperature High Pressure

This paper presents an experimental study of surface wettability on a stainless plate in a high-temperature, high-pressure environment. Using a pressure vessel, we measured contact angles of water droplets at temperatures from 20 to 300°C and a constant pressure of 15 MPa, as an indicator of macroscopic surface wettability. Measured contact angles decreased with temperature below 250°C, clustering around a straight line at temperatures below 120°C and around another line in the range from 120 to 250°C. At temperatures above 250°C, on the other hand, the contact angles remained constant, independent of temperature, and contrary to the existing theoretical model, no highly hydrophilic condition or null contact angle condition was achieved.

Wetting and Interfacial Behavior of Molten Al on Mo-Ni(Co)-Si Coated SiC Ceramic

2016 ◽  
Vol 697 ◽  
pp. 481-484 ◽  
Author(s):  
San Tuan Zhao ◽  
Xiang Zhao Zhang ◽  
Gui Wu Liu ◽  
Hong Yan Xia ◽  
Zhong Qi Shi ◽  
...  
Keyword(s):  
Contact Angle ◽  
Sessile Drop ◽  
Triple Line ◽  
Contact Angles ◽  
Strong Interactions ◽  
Interfacial Behavior ◽  
Ceramic Substrates ◽  
Sic Ceramic ◽  
Mo Content ◽  
Drop Technique

The Mo-Ni (Co)-Si metallizing coatings on the SiC ceramic substrate were prepared by vacuum cladding process. The wetting and spreading of molten Al on coated SiC ceramic substrates at 900 oC were investigated by the sessile drop technique, and the interfacial behavior of the Al/coated SiC wetting couples was analyzed. The experimental results showed that the final contact angle of Al/M20NiSi coated SiC was close to 0o. With the increase of Mo content in the Mo-Ni-Si coating, the shape of the sessile drop became very irregular due to the strong interactions between the Al drop and the coating, so it was unable to precisely characterize the contact angles of Al/Mo30NiSi and Al/Mo40NiSi systems. The final contact angle of Al/Mo10CoSi coated SiC system was also close to 0o, however, the final contact angle of Al/Mo20CoSi coated SiC system climbed to ~42o with the Mo content increasing from 10 at.% to 20 at.%. The significant increase of contact angle may be caused by the accumulation of Mo near the triple line which can impede the spreading of Al drop.

A laser interferometric study of sessile drop shape and contact angle

1985 ◽  
Vol 63 (8) ◽  
pp. 2339-2340 ◽  
Author(s):  
R. N. O'brien ◽  
Paul Saville
Keyword(s):  
Contact Angle ◽  
Sessile Drop ◽  
Contact Angles ◽  
Glass System ◽  
Drop Shape ◽  
Measured Angle ◽  
Interferometric Study ◽  
Laser Interferometric ◽  
Equal Thickness

Small contact angles, such as water on glass, have been shown to be measurable interferometrically using fringes of equal thickness after the fashion of Newton's rings. The measured angle for the water on glass system was 0.049 ± 0.006 degrees of arc.

Wettability Determination of the CO2-Reservoir Brine-Reservoir Rock System at High Pressures and High Temperature for Different Salinities

2014 ◽  
Vol 675-677 ◽  
pp. 115-119 ◽  
Author(s):  
Hai Tao Wang
Keyword(s):  
Contact Angle ◽  
High Temperature ◽  
High Pressures ◽  
Sessile Drop ◽  
Pure Water ◽  
Dynamic Contact Angle ◽  
Water System ◽  
Dynamic Contact ◽  
Reservoir Rock ◽  
Rock System

An experimental method has been developed to determine the wettability, i.e., the contact angle, of a CO2-reservoir brine-reservoir rock system at high pressures and high temperature using the axisymmetric drop shape analysis (ADSA) technique for the sessile drop case. The laboratory experiments were conducted for dynamic contact angle of CO2-reservoir brine-reservoir rock covering three interesting salinities (0 mg/L, 14224.2 mg/L and 21460.6 mg/L) at P=6–35 MPa and T=97.5 °C. For pure water system, θad (static advancing contact angel) increases from 71.69° to 107.1° as pressure of CO2 increases from 6 MPa to 35 MPa. θad decreases from 71.48° to 42.01° for the 1# brine system and from 51.21° to 23.61° for the 2# brine system as pressure of CO2 increases from 6 MPa to 35 MPa. θad for 2# brine system (21460.6 mg/L) is lower than that for 1# brine system (14224.2 mg/L) under the each same pressure.

Wetting of Compacted Nanoclay Powder by Epoxy Resin

Materials ◽  
2005 ◽  
Author(s):  
Levent Aktas ◽  
Youssef K. Hamidi ◽  
M. Cengiz Altan
Keyword(s):  
Contact Angle ◽  
Epoxy Resin ◽  
Sessile Drop ◽  
Ccd Camera ◽  
Contact Angles ◽  
Effect Of Temperature ◽  
Chemical Compositions ◽  
Low Viscosity ◽  
Static Contact ◽  
Advancing Contact Angle

Spreading behavior and advancing contact angle of a low viscosity epoxy resin on three commercially available nanoclays — Cloisite® Na+, Cloisite® 15A and Cloisite® 25A — at 52°C is investigated. In addition, effect of temperature on spreading dynamics of epoxy on Cloisite® Na+ is analyzed at 33, 52 and 77°C. For wetting experiments, nanoclay powder is compressed into 12.7mm diameter disk shaped compacts under 20MPa pressure. The surface topologies of the compacts are analyzed by scanning electron microscopy (SEM), where as energy dispersive x-ray analysis (EDXA) is utilized to quantify the chemical composition of the surface. An epoxy drop is placed on each of the compacts and spreading is monitored via a CCD camera equipped with a high magnification lens. Temporal evolution of the advancing contact angle as well as drop penetration into the nanoclay compact is determined using the drop profiles extracted from the sessile drop images. Spreading of epoxy on Cloisite® Na+ is observed to be 12-fold faster at 77°C compared to 33°C. Analogous to its spreading speed, rate of penetration of resin into the nanoclay compact increased 20-fold in the same temperature range. Behavior of different nanoclay types are assessed by repeating the wetting experiments on Cloisite® 15A and Cloisite® 25A compacts. Unlike Cloisite® Na+, which did not have a finite static contact angle, Cloisite® 15A and Cloisite® 25A yielded static contact angles of 59.2°and 40.1°, respectively. These differences are attributed to different surface energies as a result of different chemical compositions of the surfaces and dissimilar surface topologies.

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