scholarly journals Plasma-Stimulated Super-Hydrophilic Surface Finish of Polymers

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2498 ◽  
Author(s):  
Miran Mozetič
Keyword(s):  
Surface Finish ◽  
Photoelectron Spectroscopy ◽  
Oxygen Plasma ◽  
Polymer Materials ◽  
Oxygen Plasma Treatment ◽  
Hydrophilic Surface ◽  
Capacitively Coupled ◽  
Force Microscopy ◽  
The Stability ◽  
Micrometer Scale

Super-hydrophilicity is a desired but rarely reported surface finish of polymer materials, so the methods for achieving such a property represent a great scientific and technological challenge. The methods reported by various authors are reviewed and discussed in this paper. The super-hydrophilic surface finish has been reported for polymers functionalized with oxygen-rich surface functional groups and of rich morphology on the sub-micrometer scale. The oxygen concentration as probed by X-ray photoelectron spectroscopy should be above 30 atomic % and the roughness as determined by atomic force microscopy over a few nm, although most authors reported the roughness was close to 100 nm. A simple one-step oxygen plasma treatment assures for super-hydrophilicity of few polymers only, but the technology enables such a surface finish of almost any fluorine-free polymer providing a capacitively coupled oxygen plasma that enables deposition of minute quantities of inorganic material is applied. More complex methods include deposition of at least one coating, followed by surface activation with oxygen plasma. Fluorinated polymers require treatment with plasma rich in hydrogen to achieve the super-hydrophilic surface finish. The stability upon aging depends largely on the technique used for super-hydrophilization.

scholarly journals Oxygen-plasma-modified biomimetic nanofibrous scaffolds for enhanced compatibility of cardiovascular implants

2015 ◽  
Vol 6 ◽  
pp. 254-262 ◽  
Author(s):  
Anna Maria Pappa ◽  
Varvara Karagkiozaki ◽  
Silke Krol ◽  
Spyros Kassavetis ◽  
Dimitris Konstantinou ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Plasma Treatment ◽  
Photoelectron Spectroscopy ◽  
Oxygen Plasma ◽  
Cell Attachment ◽  
Oxygen Plasma Treatment ◽  
Depth Sensing ◽  
Force Microscopy ◽  
Nanofibrous Scaffolds ◽  
Cardiovascular Implants

Electrospun nanofibrous scaffolds have been extensively used in several biomedical applications for tissue engineering due to their morphological resemblance to the extracellular matrix (ECM). Especially, there is a need for the cardiovascular implants to exhibit a nanostructured surface that mimics the native endothelium in order to promote endothelialization and to reduce the complications of thrombosis and implant failure. Thus, we herein fabricated poly-ε-caprolactone (PCL) electrospun nanofibrous scaffolds, to serve as coatings for cardiovascular implants and guide tissue regeneration. Oxygen plasma treatment was applied in order to modify the surface chemistry of the scaffold and its effect on cell attachment and growth was evaluated. The conditions of the surface modification were properly adjusted in order to define those conditions of the treatment that result in surfaces favorable for cell growth, while maintaining morphological integrity and mechanical behavior. Goniometry (contact angle measurements), scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) measurements were used to evaluate the morphological and chemical changes induced by the plasma treatment. Moreover, depth-sensing nanoindentation was performed to study the resistance of the plasma-treated scaffolds to plastic deformation. Lastly, the cell studies indicated that all scaffolds were cytocompatible, with the plasma-treated ones expressing a more pronounced cell viability and adhesion. All the above findings demonstrate the great potential of these biomimetic tissue-engineering constructs as efficient coatings for enhanced compatibility of cardiovascular implants.

scholarly journals Biomimetic nanostructures for the silicone-biosystem interface: tuning oxygen-plasma treatments of polydimethylsiloxane

2017 ◽  
Vol 9 (2) ◽  
Author(s):  
Bekim Osmani ◽  
Gabriela Gerganova ◽  
Bert Müller
Keyword(s):  
Plasma Treatment ◽  
Oxygen Plasma ◽  
Dynamic Contact Angle ◽  
Dynamic Contact ◽  
Oxygen Plasma Treatment ◽  
Pdms Film ◽  
Pdms Surface ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Hydrophobic Recovery

AbstractPolydimethylsiloxanes (PDMS) have drawn attention because of their applicability in medical implants, soft robotics and microfluidic devices. This article examines the formation of dedicated nanostructures on liquid submicrometer PDMS films when exposed to oxygen-plasma treatment. We show that by using a vinyl-terminated PDMS prepolymer with a molecular weight of 800 g/mol, one can bypass the need of solvent, copolymer, or catalyst to fabricate wrinkled films. The amplitude and periodicity of the wrinkles is tuned varying the thickness of the PDMS film between 150 and 600 nm. The duration of the plasma treatment and the oxygen pressure determine the surface morphology. The amplitude was found between 30 and 300 nm with periodicities ranging from 500 to 2800 nm. Atomic force microscopy was used to measure film thickness, amplitude and wrinkle periodicity. The hydrophobic recovery of the nanostructured PDMS surface, as assessed by dynamic contact angle measurements, scales with nanostructure’s fineness, associated with an improved biocompatibility. The mechanical properties were extracted out of 10,000 nanoindentations on 50×50-μm

Ta2O5-Incorporated WO3 Nanocomposite Film for Improved Electrochromic Performance in an Acidic Condition

2006 ◽  
Vol 6 (11) ◽  
pp. 3572-3576 ◽  
Author(s):  
Hee-Sang Shim ◽  
Hyo-Jin Ahn ◽  
Youn-Su Kim ◽  
Yung-Eun Sung ◽  
Won Bae Kim
Keyword(s):  
Surface Roughness ◽  
Photoelectron Spectroscopy ◽  
Potential Cycling ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Continuous Potential ◽  
Chemical States ◽  
The Stability

We report electrochromic and electrochemical properties of a WO3-Ta2O5 nanocomposite electrode that was fabricated from co-sputtering. Transmission electron microscopy (TEM)images of the WO3-Ta2O5 nanocomposite electrode revealed that morphology of the WO3 film was changed by incorporation of Ta2O5 nanoparticles, and their chemical states were confirmed to be W6+ and Ta5+ oxides from X-ray photoelectron spectroscopy (XPS). The introduction of Ta2O5 to the WO3 film played a role in alleviating surface roughness increase during continuous potential cycling; whereas the surface roughness of the WO3 film was increased from ca. 3.0 nm to ca. 13.4 nm after 400 cycles, the roughness increase on the WO3-Ta2O5 was significantly reduced to 4.2 nm after 400 cycles, as investigated by atomic force microscopy (AFM). This improvement of the stability by adding Ta2O5 may be responsible for the enhanced electrochemical and optical properties over long-term cycling with the WO3-Ta2O5 nanocomposite electrode.

scholarly journals Optimization in Milling of Polymer Materials for High Quality Surfaces

2021 ◽  
Vol 15 (4) ◽  
pp. 512-520
Author(s):  
Ryota Uchiyama ◽  
Yuki Inoue ◽  
Fumihiro Uchiyama ◽  
Takashi Matsumura ◽  
◽  
...  
Keyword(s):  
Neural Network ◽  
Surface Quality ◽  
Surface Finish ◽  
Cutting Parameters ◽  
Polymer Materials ◽  
Optimization Approach ◽  
High Quality ◽  
Gradient Information ◽  
Surface Finishes ◽  
The Stability

High quality surfaces with transparency are required for manufacturing of plastic products. In cutting of polymer materials, surface quality is sometimes deteriorated by tarnish and/or unequal spaces of area on a surface. The cutting parameters should be determined through understanding of surface finish characteristics. This paper presents an optimization approach in milling of polycarbonate with polycrystal diamond tools in terms of the surface finish. Surfaces are finished with changing the feed rate and the clearance angle of the tool. The surface finishes, then, were observed to classify the deterioration type into welding, adhesion, and the unequal space of cutter marks with measurement of the surface profiles. The measured surface roughnesses are decomposed into the theoretical/geometrical term and the irregular term induced by the thermal and the dynamic effects. A map is presented to characterize the irregular term for the feed rates and the clearance angles. Because the surface roughnesses are measured at discrete sets of the cutting parameters in the actual cutting tests, the process design cannot be conducted to optimize the operation parameters. Therefore, a neural network is applied to associate the cutting parameters with the irregular term in the map. An approach is presented to determine the number of hidden nodes/units in the design of the neural network. Three prominent areas of welding, adhesion, and unequal spaces of the cutter marks, appear in the map of irregular roughness. The map of the surface roughness is made to optimize the cutting process. The applicable feed rates and clearance angles are determined for the tolerable surface roughnesses. The gradient information in the map is used to evaluate the stability/robustness of the surface quality for changing the parameters. The optimum parameters were determined to minimize the gradient information in the applicable feed rates and clearance angles.

Synergistic effect of polyvinylpyrrolidone noncovalently modified graphene and epoxy resin in anticorrosion application

2020 ◽  
pp. 095400832094229
Author(s):  
Shifeng Wen ◽  
Jiacheng Ma
Keyword(s):  
Epoxy Resin ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Covalent Modification ◽  
Original Structure ◽  
Graphene Layers ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Stability ◽  
Modified Graphene

In this article, polyvinylpyrrolidone (PVP) was used for the noncovalent modification on the surface of graphene. Compared with covalent modification, this method maintained the original structure of graphene layers, thereby maximizing the original properties of graphene. The π–π noncovalent bond was formed between PVP and graphene by X-ray photoelectron spectroscopy analysis, indicating that PVP successfully modified graphene. The thickness of graphene layer was measured by atomic force microscopy, which showed that the distance between graphene layers was increased by 5–6 nm, and the stability of the modified graphene in N, N-dimethylformamide was remarkably improved. The obtained composite coating by combination of the modified graphene and the epoxy resin was subjected to electrochemical impedance test to obtain the best anticorrosive effect of the coating with the graphene content of 0.3 wt%. The results showed that the addition of graphene to the epoxy resin could effectively improve the anticorrosive effect. Meanwhile, the good electrical conductivity allowed the electrons which lost from the substrate to led to air or saline rapidly, thereby reducing the combination of iron ions with oxygen and the generation of corrosion products (iron oxides).

scholarly journals Effects on the Surface and Luminescence Properties of GaAs by SF6 Plasma Passivation

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 339 ◽  
Author(s):  
Yumeng Xu ◽  
Xin Gao ◽  
Xiaolei Zhang ◽  
Zhongliang Qiao ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Photoelectron Spectroscopy ◽  
Treatment Time ◽  
Gaas Surface ◽  
Chamber Pressure ◽  
Rf Plasma ◽  
Force Microscopy ◽  
Plasma Passivation ◽  
Plasma Treatment Time ◽  
The Stability

The passivation effects of the SF6 plasma on a GaAs surface has been investigated by using the radio frequency (RF) plasma method. The RF’s power, chamber pressure, and plasma treatment time are optimized by photoluminescence (PL), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The PL intensity of passivated GaAs samples is about 1.8 times higher than those which are untreated. The oxide traps and As-As dimers can be removed effectively by using SF6 plasma treatment, and Ga-F can form on the surface of GaAs. It has also been found that the stability of the passivated GaAs surface can be enhanced by depositing SiO2 films onto the GaAs surface. These indicate that the passivation of GaAs surfaces can be achieved by using SF6 plasma treatment.

Epitaxial Growth and Characterization of NbxTi1−xO2 Rutile Films by Oxygen-Plasma-Assisted Molecular Beam Epitaxy

1995 ◽  
Vol 401 ◽  
Author(s):  
Y. Gao ◽  
S. A. Chambers
Keyword(s):  
Molecular Beam Epitaxy ◽  
Photoelectron Spectroscopy ◽  
Oxygen Plasma ◽  
Molecular Beam ◽  
High Energy ◽  
Epitaxial Films ◽  
Layer By Layer ◽  
Force Microscopy ◽  
Atomic Force

AbstractEpitaxial films of NbxTi1−xO2 rutile were grown on TiO2 (110) and (100) at 600 °C by oxygen-plasma-assisted molecular beam epitaxy using elemental Ti and Nb sources. The epitaxial films were characterized by means of reflection high-energy and low-energy electron diffraction (RHEED/LEED), x-ray photoelectron spectroscopy and diffraction (XPS/XPD), ultraviolet photoemission spectroscopy (UPS) and atomic force microscopy (AFM). The epitaxial films grow in a layer-by-layer fashion and have excellent short- and long-range structure order at x≤0.3 on TiO2(110) and at x≤0.15 on TiO2(100). However, the epitaxial films become rough and disorder at higher doping levels. Nb substitutionally incorporates at cation lattice sites, leading to NbxTi1−xO2 solid solutions. In addition, the oxidation state of Nb in the NbxTi1−xO2 films has been determined to be +4.

scholarly journals Атомный состав и морфология тонких пленок ресвератрола на поверхности окисленного кремния и поликристаллического золота

2019 ◽  
Vol 61 (3) ◽  
pp. 598
Author(s):  
А.С. Комолов ◽  
Э.Ф. Лазнева ◽  
Н.Б. Герасимова ◽  
В.С. Соболев ◽  
Ю.А. Панина ◽  
...  
Keyword(s):  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
Sample Surface ◽  
Total Surface Area ◽  
Contact Mode ◽  
Force Microscopy ◽  
Scanning Area ◽  
Before And After ◽  
The Stability ◽  
Substrate Surfaces

AbstractThe atomic composition of films of a polyphenol antioxidant, namely, resveratrol (RVL), with a thickness of up to 50 nm thermally deposited on an oxidized silicon surface is studied by the method of X-ray photoelectron spectroscopy (XPS). It is found that the surface area of pores in the RVL film is about 15% of the total surface area. The results of studying the stability of the RVL films when their surface is treated with Ar^+ ions of 3 keV under the electric current of 1 μA passing through the sample for 30 s are given. The treatment gives rise to an increase in the area of pores to 30–40%, while the ratio of the concentration of C atoms to the concentration of O atoms in the RVL film both before and after the treatment of the surface with ions does not correspond to the chemical formula of RVL molecules. Using the method of atomic force microscopy (AFM) in contact mode with a scanning area size of about 10 × 10 μm, RVL coatings deposited on the oxidized silicon and polycrystalline Au surfaces are studied. It is found that the RVL films produce grainy and porous coatings on the substrate surfaces. The typical size of grains in the sample surface plane is 150–300 nm, and the characteristic elevation reaches 30 nm.

scholarly journals Evaluation of the Mechanical Properties of ZnO Nanorods Treated with Oxygen Plasma using Atomic Force Microscopy

2021 ◽  
Vol 59 (3) ◽  
pp. 209-216
Author(s):  
Donghyuck Park ◽  
Yijun Yang ◽  
Kwanlae Kim
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Plasma Treatment ◽  
Elastic Properties ◽  
Oxygen Vacancies ◽  
Oxygen Plasma ◽  
Zno Nanorods ◽  
Oxygen Plasma Treatment ◽  
Force Microscopy ◽  
Atomic Force

Zinc oxide (ZnO) simultaneously exhibits semiconducting and piezoelectric properties. ZnO in the form of nanorods has been studied intensively for application in self-powering devices. The power generation in piezoelectric nanogenerators based on ZnO nanorods can be improved via several approaches, including an oxygen plasma treatment. When ZnO nanorods are exposed to oxygen plasma, the charge carrier concentration decreases and the piezoelectric output voltage consequently increases. However, the effects of oxygen plasma on the mechanical properties of ZnO nanorods has not been systematically studied using a precise measurement technique. Given the size of ZnO nanorods, atomic force microscopy (AFM) is a suitable method for manipulating individual ZnO nanorods and measuring their elastic properties. In the present work, we observed the effects of oxygen plasma on the elemental composition and microstructure of ZnO nanorods. First of all, the surface roughness of the ZnO nanorods was analyzed using AFM, revealing that it increased due to the etching effect of the oxygen plasma. From X-ray photoelectron spectroscopy (XPS) measurements, three distinct peaks corresponding to lattice oxygen, oxygen vacancies, and absorbed oxygen on the surface were identified. The XPS analysis results showed that oxygen vacancy defects on the ZnO nanorods were decreased by oxygen plasma treatment. Next, the effects of oxygen plasma on the elastic properties of ZnO nanorods were studied using lateral force microscopy. It was confirmed that the elastic modulus of ZnO nanorods increased due to the reduced number of defects originating from oxygen vacancies.

Effect of oxygen plasma treatment on the performance of recessed AlGaN/GaN Schottky barrier diodes

2021 ◽  
Author(s):  
Wei Mao ◽  
shihao Xu ◽  
Haiyong Wang ◽  
Cui Yang ◽  
ShengLei Zhao ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Schottky Barrier ◽  
Photoelectron Spectroscopy ◽  
Oxygen Plasma ◽  
Oxygen Plasma Treatment ◽  
Surface Oxide Layer ◽  
Schottky Barrier Diodes ◽  
X Ray ◽  
Current Collapse ◽  
Effect Of Oxygen

Abstract The treatment effect of the oxygen plasma on the performance of recessed AlGaN/GaN Schottky barrier diodes has been investigated. After the oxygen plasma treatment, the turn-on voltage and reverse leakage current are slightly changed, while the current collapse could be effectively mitigated. The X-ray photoelectron spectroscopy results suggest that a thin surface oxide layer is formed by the oxygen plasma treatment, which is responsible for the reduced current collapse. In addition, the device with oxygen plasma treatment has a relatively more inhomogeneous barrier height.

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