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 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.

Understanding gaas Native Oxides By Correlating Three Liquid Contact Angle Analysis (3LCAA) and High Resolution Ion Beam Analysis (HR-IBA) to X-Ray Photoelectron Spectroscopy (XPS) as Function of Surface Processing

MRS Advances ◽  
2019 ◽  
Vol 4 (41-42) ◽  
pp. 2249-2263
Author(s):  
Sukesh Ram ◽  
Amber A. Chow ◽  
Shaurya Khanna ◽  
Nikhil C. Suresh ◽  
Franscesca J. Ark ◽  
...  
Keyword(s):  
Surface Energy ◽  
Photoelectron Spectroscopy ◽  
Ion Beam ◽  
Surface Processing ◽  
X Ray ◽  
Native Oxides ◽  
Beam Analysis ◽  
Oxygen Coverage ◽  
Before And After ◽  
Contact Angle Analysis

ABSTRACTChemical bonding in native oxides of GaAs, before and after etching, is detected by X-Ray Photoelectron Spectroscopy (XPS). It is correlated with surface energy engineering (SEE), measured via Three Liquid Contact Angle Analysis (3LCAA), and oxygen coverage, measured by High Resolution Ion Beam Analysis (HR-IBA).Before etching, GaAs native oxides are found to be hydrophobic with an average surface energy, γT, of 33 ± 1 mJ/m2, as measured by 3LCAA. After dilute NH4OH etching, GaAs becomes highly hydrophilic and its surface energy, γT, increases by a factor 2 to a reproducible value of 66 ± 1 mJ/m2. Using HR-IBA, oxygen coverage on GaAs is found to decrease from 7.2 ± 0.5 monolayers (ML) to 3.6 ± 0.5 ML. The 1.17 ratio of Ga to As, measured by HR-IBA, remains constant after etching.XPS is used to measure oxidation of Ga and As, as well as surface stoichiometry on two locations of several GaAs(100) wafers before and after etching. The relative proportions of Ga and As are unaffected by adventitious carbon contamination. The 1.16 Ga:As ratio, measured by XPS, matches HR-IBA analysis. The proportions of oxidized Ga and As do not change significantly after etching. However, the initial ratio of As2O5 to As2O3, within the oxidized As, significantly decreases after etching from approximately 3:1 to 3:2.Absolute oxygen coverage, as a function of surface processing, is determined within 0.5 ML by HR-IBA. XPS offers insight into these modifications by detecting electronic states and phase composition changes of GaAs oxides. The changes in surface chemistry are correlated to changes in hydro-affinity and surface energies measured by 3LCAA.

scholarly journals Synthesis, Characterization and Wettability of Cu-Sn Alloy on the Si-Implanted 6H-SiC

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 906 ◽  
Author(s):  
Xiang Zhao Zhang ◽  
Pu Hao Xu ◽  
Gui Wu Liu ◽  
Awais Ahmad ◽  
Xiao Hui Chen ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Energy ◽  
Sessile Drop ◽  
Contact Angles ◽  
Graphite Layer ◽  
Sessile Drop Technique ◽  
Sic Ceramics ◽  
Sic Ceramic ◽  
Interfacial Chemical Reaction ◽  
Drop Technique

The wettability of the metal/SiC system is not always excellent, resulting in the limitation of the widespread use of SiC ceramic. In this paper, three implantation doses of Si ions (5 × 1015, 1 × 1016, 5 × 1016 ions/cm2) were implanted into the 6H-SiC substrate. The wetting of Cu-(2.5, 5, 7.5, 10) Sn alloys on the pristine and Si-SiC were studied by the sessile drop technique, and the interfacial chemical reaction of Cu-Sn/SiC wetting couples was investigated and discussed. The Si ion can markedly enhance the wetting of Cu-Sn on 6H-SiC substrate, and those of the corresponding contact angles (θ) are raised partly, with the Si ion dose increasing due to the weakening interfacial chemical reactions among four Cu-Sn alloys and 6H-SiC ceramics. Moreover, the θ of Cu-Sn on (Si-)SiC substrate is first decreased and then increased from ~62° to ~39°, and ~70° and ~140°, with the Sn concentration increasing from 2.5%, 5% and 7.5% to 10%, which is linked to the reactivity of Cu-Sn alloys and SiC ceramic and the variation of liquid-vapor surface energy. Particularly, only a continuous graphite layer is formed at the interface of the Cu-10Sn/Si-SiC system, resulting in a higher contact angle (>40°).

Ageing of modified wood. Part 1: Wetting properties of acetylated, furfurylated, and thermally modified wood

Holzforschung ◽  
2010 ◽  
Vol 64 (3) ◽  
Author(s):  
Lars Elof Bryne ◽  
Magnus E.P. Wålinder
Keyword(s):  
Contact Angle ◽  
Sessile Drop ◽  
Contact Angles ◽  
Work Of Adhesion ◽  
Base Interaction ◽  
Hydrophobic Character ◽  
Wetting Properties ◽  
Heat Treated ◽  
Contact Angle Analysis ◽  
Modified Wood

Abstract The main objective of this work was to apply contact angle analysis to predict work of adhesion (W a ) between some modified wood materials and certain thermoplastics and adhesives. Wetting properties, i.e., contact angles, were measured by the Wilhelmy method on both freshly prepared and aged veneer samples of unmodified and acetylated Scots pine, furfurylated radiata pine, and heat treated Norway spruce. The sessile drop method was used to measure contact angles on a phenol resorcinol formaldehyde, an emulsion polymer isocyanate, and a one-component polyurethane adhesive. Contact angle data were also collected from the literature on polyethylene, polyvinyl chloride, polymethyl methacrylate, polystyrene, and Nylon 6. Contact angle analysis based on the Chang-Qin-Chen model was then applied to determine so-called acid-base interaction parameters and W a between the wood samples and the selected thermoplastics and adhesives. Results show that the ageing process led to an increased hydrophobic character of unmodified, heat treated, and furfurylated wood samples. The freshly prepared acetylated wood samples had a pronounced hydrophobic character which remained approximately constant after ageing. The predicted W a between the wood and the adhesives was considerably higher than that between the wood and the thermoplastics. Furthermore, the predicted W a between the acetylated wood and both the thermoplastics and water was approximately unchanged when comparing the fresh and aged samples. In contrast, the ageing of all other wood samples resulted in a dramatic decrease of the wood-water W a and a moderate decrease of the wood-thermoplastics W a . The wood-adhesives W a , however, was unchanged for the unmodified and furfurylated wood when comparing the fresh and aged samples and even increased for heat treated and acetylated wood samples.

Measuring Surface Energies of GaAs (100) and Si (100) by Three Liquid Contact Angle Analysis (3LCAA) for Heterogeneous Nano-BondingTM

MRS Advances ◽  
2018 ◽  
Vol 3 (57-58) ◽  
pp. 3403-3411 ◽  
Author(s):  
Christian E. Cornejo ◽  
Michelle E. Bertram ◽  
Timoteo C. Diaz ◽  
Saaketh R. Narayan ◽  
Sukesh Ram ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Engineering ◽  
Ion Beam ◽  
Van Der Waals ◽  
Native Oxides ◽  
Boron Doped ◽  
Measuring Surface ◽  
Beam Analysis ◽  
Oxygen Coverage ◽  
Contact Angle Analysis

ABSTRACTAnalysis of the total surface energy γTand its three components as established by the van Oss-Chaudhury-Good Theory (vOCG) is conducted via Three Liquid Contact Angle Analysis (3LCAA). γTis correlated with the composition of the top monolayers (ML) obtained from High-Resolution Ion Beam Analysis (HR-IBA). Control of γTenables surface engineering for wafer bonding (Nano-BondingTM) and/or epitaxial growth. Native oxides on boron-doped p-Si(100) are found to average γTof 53 ± 1.4 mJ/m2) and are always hydrophilic. An HF in methanol or aqueous HF etch for 60 s always renders Si(100) hydrophobic. Its γTdecreases by 20% to 44 ± 3 mJ/m2in HF in methanol etch and by 10% to 48 ± 3 mJ/m2in aqueous HF. On the contrary, GaAs(100) native oxides are found to always be hydrophobic. Tellurium n+-doped GaAs(100) yields an average of γTof 37 ± 2 mJ/m2, 96% of which is due to the Lifshitz-Van der Waals molecular interactions (γLW= 36 ± 1 mJ/m2). However, hydrophobic GaAs(100) can be made highly hydrophilic. After etching, γTincreases by almost 50% to 66 ± 1.4 mJ/m2. 3LCAA shows that the γTincrease is due to electron acceptor and donor interactions, while the Lifshitz-van der Waals energy γLWremains constant. IBA combining the 3.039 ± 0.01 MeV oxygen nuclear resonance with <111> channeling, shows that oxygen on Si(100) decreases by 10% after aqueous HF etching, from 13.3 ± 0.3 monolayers (ML) to 11.8 ± 0.4 ML 1 hour after etch.Te-doped GaAs(100) exhibits consistent oxygen coverage of 7.2 ± 1.4 ML, decreasing by 50% after etching to a highly hydrophilic surface with 3.6 ± 0.2 oxygen ML. IBA shows that etching does not modify the GaAs surface stoichiometry to within 1% . Combining 3LCAA with HR-IBA provides a quantitative metrology to measure how GaAs and Si surfaces can be altered to a different hydroaffinity and surface termination.

scholarly journals Antifouling and Flux Enhancement of Reverse Osmosis Membrane by Grafting Poly (3-Sulfopropyl Methacrylate) Brushes

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 213
Author(s):  
Reema Mushtaq ◽  
Muhammad Asad Abbas ◽  
Shehla Mushtaq ◽  
Nasir M. Ahmad ◽  
Niaz Ali Khan ◽  
...  
Keyword(s):  
Contact Angle ◽  
Reverse Osmosis ◽  
Polymer Brushes ◽  
Surface Composition ◽  
Reverse Osmosis Membrane ◽  
Optical Profilometry ◽  
Thin Film Composite ◽  
Membrane Sample ◽  
Contact Angle Analysis ◽  
And Staphylococcus Aureus

A commercial thin film composite (TFC) polyamide (PA) reverse osmosis membrane was grafted with 3-sulfopropyl methacrylate potassium (SPMK) to produce PA-g-SPMK by atom transfer radical polymerization (ATRP). The grafting of PA was done at varied concentrations of SPMK, and its effect on the surface composition and morphology was studied by Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), optical profilometry, and contact angle analysis. The grafting of hydrophilic ionically charged PSPMK polymer brushes having acrylate and sulfonate groups resulted in enhanced hydrophilicity rendering a reduction of contact angle from 58° of pristine membrane sample labeled as MH0 to 10° for a modified membrane sample labeled as MH3. Due to the increased hydrophilicity, the flux rate rises from 57.1 L m−2 h−1 to 71.2 L m−2 h−1, and 99% resistance against microbial adhesion (Escherichia coli and Staphylococcus aureus) was obtained for MH3 after modification

scholarly journals Adhesion of Individual Attachment Setae of the Spider Cupiennius salei to Substrates With Different Roughness and Surface Energy

2021 ◽  
Vol 7 ◽  
Author(s):  
Bastian Poerschke ◽  
Stanislav N. Gorb ◽  
Clemens F. Schaber
Keyword(s):  
Surface Energy ◽  
Glass Substrate ◽  
Adhesion Force ◽  
Adhesive System ◽  
Adhesive Contact ◽  
Contact Angles ◽  
Individual Variability ◽  
Van Der Waals Interactions ◽  
Smooth Surfaces ◽  
Cupiennius Salei

Dynamic adhesion is a key ability for animals to climb smooth surfaces. Spiders evolved, convergent to geckos, a dry adhesive system made of setae branching into smaller microtrichia ending as spatulae. Several previous studies concentrated either on the whole adhesive claw tuft on the spider´s foot that consists of attachment setae or on the single adhesive contact elements, the microtrichia with spatula-shaped tips. Here, the adhesion of single setae of the spider Cupiennius salei was examined and the morphology of the pretarsus and the fine structure of the setae were studied in further detail. Using individual setae fixed to force sensing cantilevers, their adhesion at different contact angles with a glass substrate was measured as well as their adhesive performance on substrates with different roughness and on smooth surfaces with different surface energies. The results show an individual variability of the adhesive forces corresponding to the seta morphology and especially to the seta tip shape. The tip shapes of the setae vary largely even in neighboring setae of the pretarsal claw tuft that comprises approximately 2,400 setae. Regarding surface energy of the substrate, the adhesion force on hydrophobic polytetrafluoroethylene was 30% of that on a hydrophilic glass substrate, which points to the importance of both van der Waals interactions and hydrogen bonds in spider adhesion.

Corona Treatment of Filled Dual-polymer Dispersion Coatings: Surface Properties and Grease Resistance

2017 ◽  
Vol 25 (4) ◽  
pp. 257-266 ◽  
Author(s):  
Sami-Seppo Ovaska ◽  
Pavel Geydt ◽  
Ringaudas Rinkunas ◽  
Tadeusz Lozovski ◽  
Robertas Maldzius ◽  
...  
Keyword(s):  
Surface Energy ◽  
Direct Current ◽  
Photoelectron Spectroscopy ◽  
Rapeseed Oil ◽  
Surface Composition ◽  
Surface Elasticity ◽  
Contact Angles ◽  
Treatment Unit ◽  
Barrier Coating ◽  
Corona Treatment

Dispersion coating layers consisting of hydroxypropylated starch, 0–30 pph of barrier-grade talc and 0–10 pph of styrene-butadiene latex were subjected to both positive and negative direct-current corona treatments utilizing a specially developed dynamic treatment unit. The effects of the surface composition (barrier coating) on the response to the direct current corona treatment were evaluated by measuring contact angles and determining the surface energy. The effects of corona treatment on the properties of the barrier coating were further determined by measuring the contact angle of rapeseed oil and the grease resistance. It was found that the grease resistance of the corona-treated barrier coatings was substantially lower than that of untreated samples, which was ascribed to holes caused by corona discharge strike-through and to chemical changes on the treated surfaces. The corona treatment lowered the surface energy of the coatings, as indicated by an increase in the contact angles of water and rapeseed oil. Changes in the dispersion part of the surface energy were recorded, particularly after positive treatment voltage, whereas a negative discharge led to greater changes in the polar part of the surface energy. X-ray photoelectron spectroscopy (XPS) tests revealed an increase in the proportion of talc at the surface after corona treatment, which indicates a migration caused by the applied electric field. The peak force tapping mode of an atomic force microscope revealed moderate topographical changes in the coatings and a decrease in surface elasticity, supporting the migration of talc particles. In addition, significant changes in the physicochemical properties of the untreated reverse side were observed.

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