scholarly journals Development of Oxygen-Plasma-Surface-Treated UHMWPE Fabric Coated with a Mixture of SiC/Polyurethane for Protection against Puncture and Needle Threats

Fibers ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 46 ◽  
Author(s):  
Dariush Firouzi ◽  
Chan Y. Ching ◽  
Syed N. Rizvi ◽  
P. Ravi Selvaganapathy
Keyword(s):  
Oxygen Plasma ◽  
Single Layer ◽  
Areal Density ◽  
Hypodermic Needle ◽  
Resistance Force ◽  
Oxygen Plasma Treatment ◽  
Multiple Layer ◽  
Coated Fabric ◽  
Parametric Studies ◽  
Maximum Penetration

Although considerable research has been directed at developing materials for ballistic protection, considerably less has been conducted to address non-firearm threats. Even fewer studies have examined the incorporation of particle-laden elastomers with textiles for spike, knife, and needle protection. We report on a new composite consisting of ultra-high-molecular-weight polyethylene (UHMWPE) fabric impregnated with nanoparticle-loaded elastomer, specifically designed for spike- and needle-resistant garments. Failure analysis and parametric studies of particle-loading and layer-count were conducted using a mixture of SiC and polyurethane at 0, 30, and 50 wt.%. The maximum penetration resistance force of a single-layer of uncoated fabric increased up to 218–229% due to nanoparticle loading. Multiple-layer stacks of coated fabric show up to 57% and 346% improvement in spike puncture and hypodermic needle resistance, respectively, and yet were more flexible and 21–55% thinner than a multiple-layer stack of neat fabric (of comparable areal density). We show that oxygen-plasma-treatment of UHMWPE is critical to enable effective coating.

Transition from Metallic to Semiconducting Behavior in Oxygen Plasma-treated Single-layer Graphene

2011 ◽  
Vol 1336 ◽  
Author(s):  
Amirhasan Nourbakhsh ◽  
Mirco Cantoro ◽  
Tom Vosch ◽  
Geoffrey Pourtois ◽  
Johan Hofkens ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Oxygen Plasma ◽  
Treatment Time ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Oxygen Plasma Treatment ◽  
Pristine Graphene ◽  
Layer Graphene ◽  
Epoxy Groups ◽  
Semiconducting Behavior

ABSTRACTWe investigate the structural, optical and electrical properties of single-layer graphene exposed to oxygen plasma treatment. We find that the pristine semimetallic behavior of graphene disappears upon plasma treatment, in favour of the opening of a bandgap and the featuring of semiconducting properties. The metal-to-semiconductor transition observed appears to be dependent on the plasma treatment time. The semiconducting behavior is also confirmed by photoluminescence measurements. The opening of a bandgap in graphene is explained in terms of graphene surface functionalization with oxygen atoms, bonded as epoxy groups. Ab initio calculations of the density of states show more details about the oxygen–graphene interaction and its effects on the graphene optoelectronic properties, predicting no states near the Fermi level at increasing epoxy group density. The structural changes are also monitored by Raman spectroscopy, showing the progressive evolution of the sp2 character of pristine graphene to sp3, due to the lattice decoration with out-of-plane epoxy groups.

Single Layer vs Bilayer Graphene: A Comparative Study of the Effects of Oxygen Plasma Treatment on Their Electronic and Optical Properties

2011 ◽  
Vol 115 (33) ◽  
pp. 16619-16624 ◽  
Author(s):  
Amirhasan Nourbakhsh ◽  
Mirco Cantoro ◽  
Alexander V. Klekachev ◽  
Geoffrey Pourtois ◽  
Tom Vosch ◽  
...  
Keyword(s):  
Optical Properties ◽  
Comparative Study ◽  
Plasma Treatment ◽  
Oxygen Plasma ◽  
Single Layer ◽  
Bilayer Graphene ◽  
Oxygen Plasma Treatment ◽  
Electronic And Optical Properties

Low-temperature oxygen plasma treatment of single-layer molybdenum disulfide

2019 ◽  
Vol 6 (5) ◽  
pp. 055007 ◽  
Author(s):  
Anthony Akayeti ◽  
Weibing Zhang ◽  
Xiaohong Yan ◽  
Quan Wang
Keyword(s):  
Low Temperature ◽  
Plasma Treatment ◽  
Molybdenum Disulfide ◽  
Oxygen Plasma ◽  
Single Layer ◽  
Oxygen Plasma Treatment

scholarly journals Photoluminescence Quenching in Single-Layer MoS2 via Oxygen Plasma Treatment

2014 ◽  
Vol 118 (36) ◽  
pp. 21258-21263 ◽  
Author(s):  
Narae Kang ◽  
Hari P. Paudel ◽  
Michael N. Leuenberger ◽  
Laurene Tetard ◽  
Saiful I. Khondaker
Keyword(s):  
Plasma Treatment ◽  
Oxygen Plasma ◽  
Single Layer ◽  
Oxygen Plasma Treatment ◽  
Photoluminescence Quenching

High Breakdown Voltage GaN HEMT Device Fabricated on Self-Standing GaN Substrate

2013 ◽  
Vol 347-350 ◽  
pp. 1535-1539
Author(s):  
Jian Jun Zhou ◽  
Liang Li ◽  
Hai Yan Lu ◽  
Ceng Kong ◽  
Yue Chan Kong ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Breakdown Voltage ◽  
Oxygen Plasma ◽  
Cutoff Frequency ◽  
Chemical Vapor ◽  
Current Gain ◽  
Organic Chemical ◽  
Oxygen Plasma Treatment ◽  
Gan Hemt ◽  
High Breakdown Voltage

In this letter, a high breakdown voltage GaN HEMT device fabricated on semi-insulating self-standing GaN substrate is presented. High quality AlGaN/GaN epilayer was grown on self-standing GaN substrate by metal organic chemical vapor deposition. A 0.8μm gate length GaN HEMT device was fabricated with oxygen plasma treatment. By using oxygen plasma treatment, gate forward working voltage is increased, and a breakdown voltage of more than 170V is demonstrated. The measured maximum drain current of the device is larger than 700 mA/mm at 4V gate bias voltage. The maximum transconductance of the device is 162 mS/mm. In addition, high frequency performance of the GaN HEMT device is also obtained. The current gain cutoff frequency and power gain cutoff frequency are 19.7 GHz and 32.8 GHz, respectively. A high fT-LG product of 15.76 GHzμm indicating that homoepitaxy technology is helpful to improve the frequency performance of the device.

scholarly journals An Assessment of Surface Treatments for Adhesion of Polyimide Thin Films

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1955
Author(s):  
Marco Cen-Puc ◽  
Andreas Schander ◽  
Minerva G. Vargas Gleason ◽  
Walter Lang
Keyword(s):  
Flexible Electronics ◽  
Oxygen Plasma ◽  
Reactive Ion Etching ◽  
Peel Test ◽  
Scratch Test ◽  
Peel Strength ◽  
Surface Treatments ◽  
Oxygen Plasma Treatment ◽  
Polyimide Films ◽  
Ion Etching

Polyimide films are currently of great interest for the development of flexible electronics and sensors. In order to ensure a proper integration with other materials and PI itself, some sort of surface modification is required. In this work, microwave oxygen plasma, reactive ion etching oxygen plasma, combination of KOH and HCl solutions, and polyethylenimine solution were used as surface treatments of PI films. Treatments were compared to find the best method to promote the adhesion between two polyimide films. The first selection of the treatment conditions for each method was based on changes in the contact angle with deionized water. Afterward, further qualitative (scratch test) and a quantitative adhesion assessment (peel test) were performed. Both scratch test and peel strength indicated that oxygen plasma treatment using reactive ion etching equipment is the most promising approach for promoting the adhesion between polyimide films.

scholarly journals Evaluation of the Effective Microstructure Parameter of the Microwave Emission Model of Layered Snowpack for Multiple-Layer Snow

2021 ◽  
Vol 13 (10) ◽  
pp. 2012
Author(s):  
Yue Yu ◽  
Jinmei Pan ◽  
Jiancheng Shi
Keyword(s):  
Process Model ◽  
Mean Squared Error ◽  
Weighted Average ◽  
Single Layer ◽  
Microwave Emission ◽  
Emission Model ◽  
Snow Layer ◽  
Optimal Method ◽  
Microstructure Parameter ◽  
Multiple Layer

Natural snow, one of the most important components of the cryosphere, is fundamentally a layered medium. In forward simulation and retrieval, a single-layer effective microstructure parameter is widely used to represent the emission of multiple-layer snowpacks. However, in most cases, this parameter is fitted instead of calculated based on a physical theory. The uncertainty under different frequencies, polarizations, and snow conditions is uncertain. In this study, we explored different methods to reduce the layered snow properties to a set of single-layer values that can reproduce the same brightness temperature (TB) signal. A validated microwave emission model of layered snowpack (MEMLS) was used as the modelling tool. Multiple-layer snow TB from the snow’s surface was compared with the bulk TB of single-layer snow. The methods were tested using snow profile samples from the locally validated and global snow process model simulations, which follow the natural snow’s characteristics. The results showed that there are two factors that play critical roles in the stability of the bulk TB error, the single-layer effective microstructure parameter, and the reflectivity at the air–snow and snow–soil boundaries. It is important to use the same boundary reflectivity as the multiple-layer snow case calculated using the snow density at the topmost and bottommost layers instead of the average density. Afterwards, a mass-weighted average snow microstructure parameter can be used to calculate the volume scattering coefficient at 10.65 to 23.8 GHz. At 36.5 and 89 GHz, the effective microstructure parameter needs to be retrieved based on the product of the snow layer transmissivity. For thick snow, a cut-off threshold of 1/e is suggested to be used to include only the surface layers within the microwave penetration depth. The optimal method provides a root mean squared error of bulk TB of less than 5 K at 10.65 to 36.5 GHz and less than 10 K at 89 GHz for snow depths up to 130 cm.

LDI-MS examination of oxygen plasma modified polymer for designing tailored implant biointerfaces

RSC Advances ◽  
2014 ◽  
Vol 4 (50) ◽  
pp. 26240-26243 ◽  
Author(s):  
M. Gołda-Cępa ◽  
N. Aminlashgari ◽  
M. Hakkarainen ◽  
K. Engvall ◽  
A. Kotarba
Keyword(s):  
Plasma Treatment ◽  
Oxygen Plasma ◽  
Oxygen Plasma Treatment ◽  
Parylene C ◽  
Modified Polymer

A versatile parylene C coating for biomaterials was fabricated by the mild oxygen plasma treatment and examined by the use of LDI-MS..

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