scholarly journals Development and Investigation of PEDOT:PSS Composition Coated Fabrics Intended for Microwave Shielding and Absorption

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1191
Author(s):  
Vitalija Rubeziene ◽  
Julija Baltusnikaite-Guzaitiene ◽  
Ausra Abraitiene ◽  
Audrone Sankauskaite ◽  
Paulius Ragulis ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Structural Parameters ◽  
Contact Angles ◽  
Electromagnetic Properties ◽  
Microwave Range ◽  
Fiber Composition ◽  
Water Solvent ◽  
Coated Fabrics ◽  
Fabric Surface ◽  
Resistance Performance

This study presents the investigation of the electromagnetic properties and resistance performance of electrically conductive fabrics coated with composition containing the conjugated polymer system poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS). The developed fabrics were intended for electromagnetic radiation (EMR) shielding in microwave range and for absorbing microwaves in radar operating range, so as to act as radar absorbing materials (RAM). The measurements of reflection and transmission of the developed fabrics were performed in a frequency range of 2–18 GHz, which covers the defined frequencies relevant to the application. Four types of fabrics with different fiber composition (polyamide; polyamide/cotton; wool and para-aramid/viscose) were selected and coated with conductive paste using screen printing method. It was found that EMR shielding effectiveness (SE) as well as absorption properties depend not only the amount of conductive paste topped on the fabric, but also resides in the construction parameters of fabrics. Depending on such fabric structural parameters as density, mass per unit area, type of weave, a layer of shield (or coating) just sticks on the fabric surface or penetrates into fabric, changing the shield thickness and herewith turning SE results. Meanwhile, the fiber composition of fabrics influences mostly bonding between fibers and polymer coating. To improve the resistance performance of the developed samples, a conventional textile surface modification technique, atmospheric plasma treatment, was applied. Initially, before plasma treatment and after treatment the fabrics were evaluated regarding an aqueous liquid repellency test, measuring the contact angles for the water solvent. The influence of plasma treatment on resistance performance of coated fabrics was evaluated by subjecting the plasma treated samples and untreated samples to abrasion in the Martindale abrasion apparatus and to multiplex washing cycles. These investigations revealed that applied plasma treatment visibly improved abrasion resistance as a result of better adhesion of the coating. However, washing resistance increased not so considerably.

scholarly journals Electrothermal Modeling and Analysis of Polypyrrole-Coated Wearable E-Textiles

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 550
Author(s):  
Akif Kaynak ◽  
Ali Zolfagharian ◽  
Toby Featherby ◽  
Mahdi Bodaghi ◽  
M. A. Parvez Mahmud ◽  
...  
Keyword(s):  
Finite Element ◽  
Plasma Treatment ◽  
Joule Heating ◽  
Electrical Resistance ◽  
Atmospheric Plasma ◽  
Maximum Temperature ◽  
Element Analysis ◽  
Numerical Work ◽  
Coated Fabrics ◽  
Fabric Surface

The inhomogeneity of the resistance of conducting polypyrrole-coated nylon–Lycra and polyester (PET) fabrics and its effects on surface temperature were investigated through a systematic experimental and numerical work including the optimization of coating conditions to determine the lowest resistivity conductive fabrics and establish a correlation between the fabrication conditions and the efficiency and uniformity of Joule heating in conductive textiles. For this purpose, the effects of plasma pre-treatment and molar concentration analysis of the dopant anthraquinone sulfonic acid (AQSA), oxidant ferric chloride, and monomer pyrrole was carried out to establish the conditions to determine the sample with the lowest electrical resistance for generating heat and model the experiments using the finite element modeling (FEM). Both PET and nylon-Lycra underwent atmospheric plasma treatment to functionalize the fabric surface to improve the binding of the polymer and obtain coatings with reduced resistance. Both fabrics were compared in terms of average electrical resistance for both plasma treated and untreated samples. The plasma treatment induced deep black coatings with lower resistance. Then, heat-generating experiments were conducted on the polypyrrole (PPy) coated fabrics with the lowest resistance using a variable power supply to study the distribution and maximum value of the temperature. The joule heating model was developed to predict the heating of the conductive fabrics via finite element analysis. The model was based on the measured electrical resistance at different zones of the coated fabrics. It was shown that, when the fabric was backed with neoprene insulation, it would heat up quicker and more evenly. The average electrical resistance of the PPy-PET sample used was 190 Ω, and a maximum temperature reading of 43 °C was recorded. The model results exhibited good agreement with thermal camera data.

Research of Electromagnetic Properties of Composite Materials on the Basis of MWNTs in Microwave Range

2014 ◽  
Vol 1040 ◽  
pp. 142-147
Author(s):  
Valentine I. Suslyaev ◽  
Vladimir L. Kuznetsov ◽  
S.I. Moseenkov ◽  
Evgeniy Yu. Korovin ◽  
D.V. Krasnikov
Keyword(s):  
Carbon Nanotubes ◽  
Composite Materials ◽  
Structural Parameters ◽  
Multiwall Carbon Nanotubes ◽  
Dielectric Permeability ◽  
Electromagnetic Properties ◽  
Microwave Range ◽  
Multilayer Carbon Nanotubes ◽  
Multiwall Carbon ◽  
Parameters Calculation

In this paper electromagnetic properties of composite materials based on polymethylmethacrylate and multiwall carbon nanotubes (MWCNTs) are investigated. Carbon nanotubes are received with application of various types of catalysts and have various structural parameters. Calculation of dielectric permeability of the synthesised materials is carried out. Dependence of electromagnetic properties of composite materials on concentration and structure used multilayer carbon nanotubes is shown.

scholarly journals Treatment of wood with atmospheric plasma discharge: study of the treatment process, dynamic wettability and interactions with a waterborne coating

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Jure Žigon ◽  
Matjaž Pavlič ◽  
Pierre Kibleur ◽  
Jan Van den Bulcke ◽  
Marko Petrič ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Treatment Process ◽  
Beech Wood ◽  
Treated Wood ◽  
Plasma Discharge ◽  
Contact Angles ◽  
Atmospheric Plasma ◽  
Waterborne Coating ◽  
Spruce Wood ◽  
The Impact

AbstractPlasma treatment is becoming a mature technique for modification of surfaces of various materials, including wood. A better insight in the treatment process and the impact of the plasma on properties of wood bulk are still needed. The study was performed on Norway spruce and common beech wood, as well as their thermally modified variations. The formations of the airborne discharge, as well as mass changes of the treated wood, were monitored. The impact of such treatment on wood-coating interaction was investigated by evaluating the dynamic wettability and penetration into wood. At the wood surface, plasma streamers were observed more intense on denser latewood regions. Wood mass loss was higher with increasing number of passes through the plasma discharge and was lower for thermally modified wood than for unmodified wood. Plasma treatment increased the surface free energy of all wood species and lowered the contact angles of a waterborne coating, these together indicating enhanced wettability after treatment. Finally, the distribution and penetration depth of the coating were studied with X-ray microtomography. It was found that the coating penetrated deeper into beech than into spruce wood. However, the treatment with plasma increased the penetration of the coating only into spruce wood.

scholarly journals Electromagnetic properties of LaCa3Fe5Oi2in the microwave range

2016 ◽  
Vol 110 ◽  
pp. 012106
Author(s):  
V V Golenkina ◽  
S A Ghyngazov ◽  
V I Suslyaev ◽  
E Yu Korovin ◽  
G E Kuleshov ◽  
...  
Keyword(s):  
Electromagnetic Properties ◽  
Microwave Range

scholarly journals Benefits of Nonthermal Atmospheric Plasma Treatment on Dentin Adhesion

2018 ◽  
Vol 43 (6) ◽  
pp. E288-E299 ◽  
Author(s):  
AP Ayres ◽  
PH Freitas ◽  
J De Munck ◽  
A Vananroye ◽  
C Clasen ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Water Storage ◽  
Contact Angles ◽  
The Other ◽  
Atmospheric Plasma ◽  
Hybrid Layer ◽  
Water Contact ◽  
Dentin Surface

SUMMARY Objectives: This study aimed to evaluate the influence of two nonthermal atmospheric plasma (NTAP) application times and two storage times on the microtensile bond strength (μTBS) to dentin. The influence of NTAP on the mechanical properties of the dentin-resin interface was studied by analyzing nanohardness (NH) and Young's modulus (YM). Water contact angles of pretreated dentin and hydroxyapatite blocks were also measured to assess possible alterations in the surface hydrophilicity upon NTAP. Methods and Materials: Forty-eight human molars were used in a split-tooth design (n=8). Midcoronal exposed dentin was flattened by a 600-grit SiC paper. One-half of each dentin surface received phosphoric acid conditioning, while the other half was covered with a metallic barrier and remained unetched. Afterward, NTAP was applied on the entire dentin surface (etched or not) for 10 or 30 seconds. The control groups did not receive NTAP treatment. Scotchbond Universal (SBU; 3M ESPE) and a resin-based composite were applied to dentin following the manufacturer's instructions. After 24 hours of water storage at 37°C, the specimens were sectioned perpendicular to the interface to obtain approximately six specimens or bonded beams (approximately 0.9 mm2 in cross-sectional area) representing the etch-and-rinse (ER) approach and another six specimens representing the self-etch (SE) approach. Half of the μTBS specimens were immediately loaded until failure, while the other half were first stored in deionized water for two years. Three other bonded teeth were selected from each group (n=3) for NH and YM evaluation. Water contact-angle analysis was conducted using a CAM200 (KSV Nima) goniometer. Droplet images of dentin and hydroxyapatite surfaces with or without 10 or 30 seconds of plasma treatment were captured at different water-deposition times (5 to 55 seconds). Results: Two-way analysis of variance revealed significant differences in μTBS of SBU to dentin after two years of water storage in the SE approach, without differences among treatments. After two years of water aging, the ER control and ER NTAP 10-second groups showed lower μTBS means compared with the ER NTAP 30-second treated group. Nonthermal atmospheric plasma resulted in higher NH and YM for the hybrid layer. The influence of plasma treatment in hydrophilicity was more evident in the hydroxyapatite samples. Dentin hydrophilicity increased slightly after 10 seconds of NTAP, but the difference was higher when the plasma was used for 30 seconds. Conclusions: Dentin NTAP treatment for 30 seconds contributed to higher μTBS after two years of water storage in the ER approach, while no difference was observed among treatments in the SE evaluation. This result might be correlated to the increase in nanohardness and Young's modulus of the hybrid layer and to better adhesive infiltration, since dentin hydrophilicity was also improved. Although some effects were observed using NTAP for 10 seconds, the results suggest that 30 seconds is the most indicated treatment time.

Surface Modification of Cellulose Membrane by Air Plasma Treatment

2013 ◽  
Vol 770 ◽  
pp. 112-115
Author(s):  
Nawal Binhayeeniyi ◽  
Adinan Jehsu ◽  
Mancharee Sukpet ◽  
Safitree Nawae
Keyword(s):  
Surface Modification ◽  
Plasma Treatment ◽  
Surface Modifications ◽  
Contact Angles ◽  
Cellulose Membrane ◽  
Air Plasma ◽  
Before And After ◽  
Cellulose Membranes ◽  
Hydrophilic Membranes ◽  
Air Plasma Treatment

Low-temperature air plasma was used to treat the cellulose membranes by varying the period of time from 10 to 30 minutes. The surfaces of membranes were changed from hydrophobic to hydrophilic membranes. The contact angles of treated membranes were increased when increasing time to treat. The surface modifications of membrane before and after treated were characterized by SEM. It is shown that air plasma treatment is used to improve the roughness. The dielectric property was also studied.

Analysis of load distribution and contact stiffness of the single-nut ball screw based on the whole rolling elements model

2019 ◽  
Vol 43 (3) ◽  
pp. 344-365 ◽  
Author(s):  
Ye Chen ◽  
Chun-yu Zhao ◽  
Si-yu Zhang ◽  
Xian-li Meng
Keyword(s):  
Load Distribution ◽  
Contact Stiffness ◽  
Structural Parameters ◽  
Contact Angles ◽  
Ball Screw ◽  
Distribution Model ◽  
Axial Stiffness ◽  
Feed System ◽  
Normal Contact ◽  
Rolling Elements

This paper aims to investigate the load distribution and contact stiffness characteristics of the single-nut ball screw pair (SNBSP). First, the transformed relationship of coordinate systems is established. Then, the whole rolling elements load distribution model of the SNBSP is presented. Based on this, the whole rolling elements contact stiffness model is obtained. Applying the Newton–Raphson iterative method to solve the model, the normal force of rolling elements and the contact angles between balls and raceway surface are determined. The calculation results are reasonably consistent with those of the half pitch model. Then, the local contact stiffness and global contact stiffness are obtained. Furthermore, the effects of axial load and structural parameters of the SNBSP on the normal contact force, contact angle, and local and global contact stiffness are discussed using numeric analysis. Finally, a dynamic model of the z-axis feed system with time-varying axial stiffness is established, and the accuracy of the model is verified by experiments.

scholarly journals Superhydrophobic Fabrics with Mechanical Durability Prepared by a Two-Step Plasma Processing Method

Coatings ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 351 ◽  
Author(s):  
Kosmas Ellinas ◽  
Angeliki Tserepi ◽  
Evangelos Gogolides
Keyword(s):  
Surface Energy ◽  
Plasma Deposition ◽  
Contact Angle Hysteresis ◽  
Plasma Processing ◽  
High Water ◽  
Contact Angles ◽  
Processing Method ◽  
Static Contact ◽  
Mechanical Durability ◽  
Fabric Surface

Most studies on superhydrophobic fabrics focus on their realization using additive manufacturing (bottom-up) techniques. Here we present the direct modification of three different fabrics using a plasma-based method to obtain anti-adhesive and self-cleaning properties. A two-step plasma processing method is used: (a) for the creation of micro-nanoscale features on the fabric surface (plasma texturing step) and (b) the minimization of the fabric surface energy (by a short plasma deposition step of a very thin, low surface energy layer). The entire process takes only 14 min and all fabrics after processing exhibit high water static contact angles (WSCA > 150°), low contact angle hysteresis (CAH < 7°) and advantageous mechanical durability against hand-rumpling. The method is simple and generic, and it can be therefore expanded to other polymeric fabrics (i.e., acrylic) in addition to polyester, without any limitation rising from the weaving characteristics of the fabric or the starting nature of the material (i.e., hydrophobic or hydrophilic).

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