Surface Treatments of 4H-SiC Evaluated by Contact Angle Measurement

2011 ◽  
Vol 679-680 ◽  
pp. 374-377 ◽  
Author(s):  
Tomoaki Hatayama ◽  
Hiroyuki Suzuki ◽  
Hidenori Koketsu ◽  
Hiroshi Yano ◽  
Takashi Fuyuki
Keyword(s):  
Contact Angle ◽  
Oxide Layer ◽  
Photoelectron Spectroscopy ◽  
Contact Angle Measurement ◽  
Contact Angles ◽  
Angle Measurement ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements ◽  
Substrate Surfaces

Surface properties of the 4H-SiC (0001) Si faces could be evaluated by the contact angle measurements with water droplet method, X-ray photoelectron spectroscopy and an atomic force microscope. The contact angles do not depend on the surface roughness under 3nm. The substrate surfaces with the contact angles over 30o will be terminated by hydrogen related species. The contact angles around 20o on 4H-SiC is caused by the removal of oxide layer with fluoride acid and terminated subsequently by the -CF species on the surface. The hydrophile surface of 4H-SiC is caused by the formation of chemical oxide layer as well as the case of the silicon wafers.

Surface Modification of Fluorosilicone Acrylate RGP Contact Lens by Low-Temperature Ammonia Plasma

2009 ◽  
Vol 610-613 ◽  
pp. 1273-1277 ◽  
Author(s):  
Li Ren ◽  
Lian Na Zhao ◽  
Shi Heng Yin ◽  
Ying Jun Wang ◽  
Hao Chen ◽  
...  
Keyword(s):  
Contact Angle ◽  
Low Temperature ◽  
Plasma Treatment ◽  
Contact Lens ◽  
Photoelectron Spectroscopy ◽  
Ammonia Plasma ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements ◽  
Surface Contact Angle

In order to improve the surface hydrophilicity and the resistance to protein deposition of fluorosilicone acrylate RGP (rigid gas permeable) contact lens, low temperature ammonia plasma treatment was used to modify the lens surface. The changes of surface structures and properties were characterized by contact angle analyzer, X-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM). Effects of exposure time and plasma generating power on surface properties of the RGP contact lens were investigated. The surface contact angle measurements showed a great improvement of hydrophilicity after plasma treatment. XPS analysis indicated that the oxygen content and the nitrogen content increased remarkably after ammonia plasma treatment. Furthermore, the content of the hydrophilic group O-C=O/N-C=O on the surface increased and the content of the hydrophobic group CF2 decreased after plasma treatment. AFM results showed that ammonia plasma could lead to surface etching.

Measurement and improvement of the adhesion of copper to polyimide

1999 ◽  
Vol 14 (10) ◽  
pp. 4025-4034 ◽  
Author(s):  
M. Menezes ◽  
I. M. Robertson ◽  
H. K. Birnbaum
Keyword(s):  
Contact Angle ◽  
Interfacial Adhesion ◽  
Reasonable Agreement ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Polyimide Substrate ◽  
Copper Clusters ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Strength Of Adhesion

A contact angle measurement technique has been used to obtain an estimate of the interfacial energy and thermodynamic adhesive strength between copper and polyimide [pyromellitic dyanhydride oxydianalyn (PMDA-ODA) and p-phenylene biphenyltetracarboinide (BPDA-PDA)]. Values of the strength of adhesion from these contact angle measurements are in reasonable agreement with values calculated using the Girifalco–Good–Fowkes nonpolar interfacial adhesion theory. Based on the surface energy it was predicted and experimentally observed that small copper clusters would embed into the polymer matrix if heated under ultrahigh vacuum conditions at temperatures near Tg of the polymer. Controlled embedding of nanometer clusters was utilized to produce a textured interface, where the partially embedded clusters acted as “nanonails” to anchor a metal overlayer to the underlying polyimide substrate. These nanonails greatly increased the bonding between the copper overlayer and the polyimide, as demonstrated by mechanical debonding studies.

scholarly journals The influence of alumino-silicate matrix composition on surface hydrophobic properties

2019 ◽  
Vol 51 (2) ◽  
pp. 163-173 ◽  
Author(s):  
Ljiljana Kljajevic ◽  
Zuzana Melichova ◽  
Danilo Kisic ◽  
Milos Nenadovic ◽  
Bratislav Todorovic ◽  
...  
Keyword(s):  
Contact Angle ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Matrix Composition ◽  
Homogeneous Surface ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Sem Micrograph ◽  
Alumino Silicate

The purpose of this investigation is to investigate the hydrophobicity of geopolymers, new alumino-silicate materials and the influence of Si/Al ratio on their surface properties. Contact angle measurement (CAM) as reliable indicator of hydrophobicity was determined for synthesized geopolymers using water and ethylene-glycol as reference liquids. Geopolymers were synthesized from various precursors: kaolin, bentonite and diatomite. Characterization of phase structure and microstructure was performed by XRD, FTIR, SEM/EDX methods. Contact angle measurements confirmed that the geopolymers synthesized from metakaolin are the most porous, which can be explained by the smallest Si/Al ratio. The maximum value of contact angle and free surface energy (110.2 mJ/m2) has been achieved for geopolymer synthesized by diatoms (GPMD). SEM micrograph of GPMD shows a homogeneous surface with some longitudinal cavities in the gel and is significantly different from the micrographs of other two geopolymer samples, GPMB and GPMK.

Structure of Silane Films and their Adhesion Properties

1995 ◽  
Vol 407 ◽  
Author(s):  
Y. Carolina Araujo ◽  
Pedro G. Toledo
Keyword(s):  
Contact Angle ◽  
Surface Coverage ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Flow In Porous Media ◽  
Adhesion Properties ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Glass Surfaces

ABSTRACTSilane films, their structure and stability, are of great interest in processes such as flow in porous media, mineral flotation, chromatography and corrosion. Here, the structure of octadecyl thriclorosilane (OTS) films on glass surfaces is studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM), their adhesion properties by contact angle measurements and adhesion tests. Complete glass surface coverage by the silane is attained after an immersion time tc characteristic of the OTS compound. The time evolution of the OTS films regarding surface coverage is monitored by SEM with a BSE detector, by measuring the OTS film thicknesses from XPS data, by AFM and by contact angle measurement. At tc the structure of the films changes from micromolecular to macromolecular. Below tc the glass coverage has a fractal geometry and various degrees of hydrophobicity are possible. At t > tc the surface coverage is complete and the contact angle achieved a well defined constant value.

Effects of Surface Treatments of Polycaprolactone Scaffolds on their Properties

2013 ◽  
Vol 747 ◽  
pp. 178-181 ◽  
Author(s):  
Wasana Kosorn ◽  
Boonlom Thavornyutikarn ◽  
Wanida Janvikul
Keyword(s):  
Contact Angle ◽  
Plasma Treatment ◽  
Alkaline Hydrolysis ◽  
Photoelectron Spectroscopy ◽  
Atomic Ratio ◽  
Contact Angle Measurement ◽  
Contact Angles ◽  
Angle Measurement ◽  
Water Contact ◽  
Oh Groups

Polycaprolactone (PCL) was surface modified with alkaline hydrolysis by NaOH and/or low pressure oxygen (O2) plasma treatment. The hydrolysis was conducted in two different stages: one was performed prior to PCL scaffold fabrication by a high pressure supercritical CO2 technique; the other was carried out after the fabrication. The resulting hydrolyzed PCL scaffolds, with pore sizes in the range of 150-250 μm, were denoted as pre-HPCL and post-HPCL, respectively. Both non-hydrolyzed and hydrolyzed PCL scaffolds were subsequently subjected to the plasma treatment, to further enhance the hydrophilicity of the scaffolds. The surface morphology, wettability and chemical composition of all PCL scaffolds were analyzed by scanning electron microscopy (SEM), water contact angle measurement, and X-ray photoelectron spectroscopy (XPS), respectively. It was found that the surface of the scaffolds turned from fairly smooth to highly rough after the hydrolysis and plasma treatment, particularly when both treatments were in use. The post-hydrolysis induced more surface roughness, compared to the pre-hydrolysis. In addition, the water contact angles on the scaffolds enormously reduced after the treatments; plasma treatment, however, showed a more prominent effect than the alkaline hydrolysis. Although expressing a zero-degree contact angle, the plasma-treated pre-HPCL scaffold was wetted more readily than the plasma-treated post-HPCL. These were in good agreement with the XPS results; interestingly, the plasma-treated pre-HPCL scaffold exhibited the greatest O/C atomic ratio among the PCL scaffolds. This indicated its highest extent of PCL chain oxidation, a degradation of ester groups into-COOH and-OH groups.

Optimal Number of Contact Angle Measurements on Pyrite Surface

2014 ◽  
Vol 926-930 ◽  
pp. 17-21
Author(s):  
Lukas Koval ◽  
Jarmila Drozdova
Keyword(s):  
Contact Angle ◽  
Standard Deviation ◽  
Statistical Evaluation ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Optimal Number ◽  
Pyrite Surface ◽  
Quick Method ◽  
Angle Measurements ◽  
Contact Angle Measurements

Contact angle measurement is a simple and quick method that expresses the surface wettability. Resulting values vary and depend on many factors that significantly affect the interpretation of results. In this paper a set of seventeen samples from different deposits with different genesis were subjected to a statistical evaluation, to determine the optimal number of measurements needed to obtain the desired standard deviation.

scholarly journals Separation of Water/Oil Emulsions by an Electrospun Copolyamide Mat Covered with a 2D Ti3C2Tx MXene

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3171
Author(s):  
AbdolAli Moghaddasi ◽  
Patrik Sobolčiak ◽  
Anton Popelka ◽  
Igor Krupa
Keyword(s):  
Contact Angle ◽  
Vegetable Oil ◽  
Separation Efficiency ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements ◽  
Oil Emulsions ◽  
Uv Transmittance ◽  
Stock Solutions

Purpose: Copolyamide 6,10 (coPA) electrospun mats were covered with multilayered (ML) and single-layered (SL) MXene (Ti3C2Tx) as a membrane for the separation of water/vegetable oil emulsions. Methods: Prepared membranes were characterized by atomic force microscopy (AFM), profilometry, the contact angle measurements of various liquids in air, and the underwater contact angle of vegetable oil. The separation efficiency was evaluated by measuring the UV transmittance of stock solutions compared to the UV transmittance of the filtrate. Results: The MXene coating onto coPA mats led to changes in the permeability, hydrophilicity, and roughness of the membranes and enhanced the separation efficiency of the water/vegetable oil emulsions containing 10, 100, and 1000 ppm of sunflower vegetable oil. It was found that membranes were highly oleophobic (>124°) under water, unlike in air, where the membranes showed high oleophobicity (<5°). The separation efficiency of water/oil emulsions for both types of covered membranes reached over 99%, with a surface coverage of 3.2 mg/cm2 Ti3C2Tx (for ML-Ti3C2Tx) and 2.9 mg/cm2 (for SL-Ti3C2Tx). Conclusions: The separation efficiency was greater than 98% for membranes covered with 2.65 mg/cm2 of ML-Ti3C2Tx, whereas the separation efficiency for membranes containing 1.89 and 0.77 mg/cm2 was less than 90% for all studied emulsion concentrations.

Effect of Plasma-Induced Polymerization on Contact Angle of Paper

2011 ◽  
Vol 396-398 ◽  
pp. 1619-1623
Author(s):  
Zhao Ping Song ◽  
Jun Rong Li ◽  
Hui Ning Xiao
Keyword(s):  
Contact Angle ◽  
Photoelectron Spectroscopy ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Polymer Grafting ◽  
Hydrophobic Property ◽  
Cellulose Fibres ◽  
Water Contact ◽  
X Ray ◽  
Factors Associated

Hydrophobic modification of cellulose fibres was conducted by plasma-induced polymer grafting in an attempt to increase the hydrophobicity of paper. Two hydrophobic monomers, i.e., butyl acrylate (BA) and 2-ethylhexyl acrylate (2-EHA) were grafted on cellulose fibres, induced by atmospheric cold plasma. Various influencing factors associated with the plasma-induced grafting were investigated, including the contact time and reaction temperature with monomers, and the dosage of monomers. Contact-angle measurement, infrared spectrum (IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were used to ascertain the occurrence of the grafting. The results showed that the hydrophobic property of the modified paper sheet was improved significantly after the plasma-induced grafting. The water contact angle on the surface of the paper reached up to higher than125°.

Wettability measurements on two sandstones: an experimental investigation before and after CO2 flooding

2020 ◽  
Vol 60 (1) ◽  
pp. 117
Author(s):  
Cut Aja Fauziah ◽  
Emad A. Al-Khdheeawi ◽  
Ahmed Barifcani ◽  
Stefan Iglauer
Keyword(s):  
Contact Angle ◽  
Co2 Storage ◽  
Contact Angle Measurement ◽  
Contact Angles ◽  
Angle Measurement ◽  
Co2 Injection ◽  
Co2 Flooding ◽  
Berea Sandstone ◽  
Before And After ◽  
Carbon Dioxide Co2

Wettability of rock–fluid systems is an important for controlling the carbon dioxide (CO2) movement and the capacities of CO2 geological trapping mechanisms. Although contact angle measurement is considered a potentially scalable parameter for evaluation of the wettability characteristics, there are still large uncertainties associated with the contact angle measurement for CO2–brine–rock systems. Thus, this study experimentally examined the wettability, before and after flooding, of two different samples of sandstone: Berea and Bandera grey sandstones. For both samples, several sets of flooding of brine (5 wt % NaCl + 1 wt % KCl in deionised water), CO2-saturated (live) brine and supercritical CO2 were performed. The contact angle measurements were conducted for the CO2–sandstone system at two different reservoir pressures (10 and 15 MPa) and at a reservoir temperature of 323 K. The results showed that both the advancing and receding contact angles of the sandstone samples after flooding were higher than that measured before flooding (i.e. after CO2 injection the sandstones became more CO2-wet). Moreover, the Bandera grey samples had higher contact angles than Berea sandstone. Thus, we conclude that CO2 flooding altered the sandstone wettability to be more CO2-wet, and Berea sandstone had a higher CO2 storage capacity than Bandera grey sandstone.

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