Effects of conductive polymer composite layering on EMI shielding during additive manufacturing

MRS Advances ◽  
2019 ◽  
Vol 4 (38-39) ◽  
pp. 2153-2159 ◽  
Author(s):  
Eugene Zakar ◽  
Theodore Anthony ◽  
Madan Dubey

Abstract:Spin coating and drop casting are viable methods for rapid and low-cost additive manufacturing of components for flexible devices and sensors. We investigated the cumulative effects of layering a conductive polymer composite 2 wt% MWCNT filler in PEDOT:PSS on a Mylar substrate for application to electromagnetic interference (EMI) shielding. The optical transmittace of spin coated composite layers is 90%, 45%, and 20% with a thickness of 0.05 µm, 0.15 µm, and 0.45 µm respectively. Drop cast composite layers have 0% transmittance due to their much greater starting thickness of 4.4 µm. The addition of isopropyl alcohol (IPA) to the solution mixture and substrate heating to 40 °C improves the conductivity, and drying time of the cured composite layers to 10 min. This study shows that the cumulative effects of composite layering are additive, but the electrical properties do not scale the same way. A significant increase in the EMI SE is mainly attributed to the enhanced electrical conductivity of the composite. The insertion of a 50 µm gap in between two 15 µm composite layers accentuates the EMI shielding effectiveness (SE) significantly to a peak of 21 dB within a narrow frequency range in the Ku-band tested.

2020 ◽  
Vol 8 (18) ◽  
pp. 9146-9159 ◽  
Author(s):  
Hongji Duan ◽  
Huixin Zhu ◽  
Jiefeng Gao ◽  
Ding-Xiang Yan ◽  
Kun Dai ◽  
...  

An ultraefficient EMI shielding WPU composite foam with extremely low reflection is achieved via ingenious asymmetric conductive network design.


2011 ◽  
Vol 31 (4) ◽  
Author(s):  
Habibun Nabi Muhammad Ekramul Mahmud ◽  
Anuar Kassim

Abstract Conducting polymer films produced by electropolymerization technique are highly conductive, simple, and suitable for use especially in electronic devices. An attempt has been made to produce polypyrrole-poly(vinyl alcohol) (PPy-PVA) conducting polymer composite films using 0.1 m p-toluene sulfonate dopant at a potential of 1.2 V (vs. standard calomel electrode) on indium tin oxide glass electrode. The potential application of the prepared PPy-PVA conducting polymer composite films as an electromagnetic interference (EMI) shielding material has been investigated in the present study. The EMI shielding effectiveness of PPy-PVA composite films prepared from different experimental conditions was analyzed in the microwave frequency range of 8–12 GHz. The shielding effectiveness of 45.67–35.7 dB has been demonstrated by PPy-PVA conducting polymer composite films, which appears to be very attractive in any EMI shielding applications where a minimum shielding effectiveness of 35 dB is required.


2014 ◽  
Vol 1064 ◽  
pp. 83-88 ◽  
Author(s):  
A. Ansri ◽  
M. Hamouni ◽  
S. Khaldi

The purpose of this communication is to study the effect of the nature of the polymer layer on the electromagnetic shielding effectiveness of a multilayer organic based composite material. Our work is divided into two parts. In the first part, we set different layer thicknesses and the frequency is varied. In the second part, we set the frequency and do vary the nature of the polymer layer and the thickness of the different layers. The different results obtained we show that the efficiency is strongly influenced by the nature of the polymer layer.


2020 ◽  
Vol 9 (1) ◽  
pp. 768-788
Author(s):  
Emayaruba G. Barathi Dassan ◽  
Aslina Anjang Ab Rahman ◽  
Mohd Shukur Zainol Abidin ◽  
Hazizan Md Akil

AbstractThe growth of the application of electronic devices has created a new form of pollution known as noise or radio frequency interference, electromagnetic radiation, or electromagnetic interference (EMI), which results in the malfunction of equipment. A new carbon-based polymer composite has been unlocked through the discovery of polymer composites. Carbon nanotubes (CNTs) have shown potential as reinforcement fillers in polymer to enhance an EMI shielding material owing to their large specific surface area, well-defined 3D networking structure, and unique electronic structure. The main focus of this review is the role of CNT as fillers in intrinsic conducting polymer and conducting polymer composite. The factors that influence EMI shielding performance are also included in this review. The roles of the size; shape; and electronic, mechanical, and chemical properties of nanomaterials in tuning the EMI shielding effectiveness of polymer hybrid are emphasized. The structural design of CNT polymer composite has been reviewed as well. Future research direction has been proposed to overcome the current technological limitations and realize the most advanced EMI shielding materials for future use. The composites have a potential to replace traditional shielding materials owing to their advantageous properties.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Rongliang Yang ◽  
Xuchun Gui ◽  
Li Yao ◽  
Qingmei Hu ◽  
Leilei Yang ◽  
...  

AbstractLightweight, flexibility, and low thickness are urgent requirements for next-generation high-performance electromagnetic interference (EMI) shielding materials for catering to the demand for smart and wearable electronic devices. Although several efforts have focused on constructing porous and flexible conductive films or aerogels, few studies have achieved a balance in terms of density, thickness, flexibility, and EMI shielding effectiveness (SE). Herein, an ultrathin, lightweight, and flexible carbon nanotube (CNT) buckypaper enhanced using MXenes (Ti3C2Tx) for high-performance EMI shielding is synthesized through a facile electrophoretic deposition process. The obtained Ti3C2Tx@CNT hybrid buckypaper exhibits an outstanding EMI SE of 60.5 dB in the X-band at 100 μm. The hybrid buckypaper with an MXene content of 49.4 wt% exhibits an EMI SE of 50.4 dB in the X-band with a thickness of only 15 μm, which is 105% higher than that of pristine CNT buckypaper. Furthermore, an average specific SE value of 5.7 × 104 dB cm2 g−1 is exhibited in the 5-μm hybrid buckypaper. Thus, this assembly process proves promising for the construction of ultrathin, flexible, and high-performance EMI shielding films for application in electronic devices and wireless communications.


2021 ◽  
pp. 108128652110214
Author(s):  
Xiaodong Xia ◽  
George J. Weng

Recent experiments have revealed two distinct percolation phenomena in carbon nanotube (CNT)/polymer nanocomposites: one is associated with the electrical conductivity and the other is with the electromagnetic interference (EMI) shielding. At present, however, no theories seem to exist that can simultaneously predict their percolation thresholds and the associated conductivity and EMI curves. In this work, we present an effective-medium theory with electrical and magnetic interface effects to calculate the overall conductivity of a generally agglomerated nanocomposite and invoke a solution to Maxwell’s equations to calculate the EMI shielding effectiveness. In this process, two complex quantities, the complex electrical conductivity and complex magnetic permeability, are adopted as the homogenization parameters, and a two-scale model with CNT-rich and CNT-poor regions is utilized to depict the progressive formation of CNT agglomeration. We demonstrated that there is indeed a clear existence of two separate percolative behaviors and showed that, consistent with the experimental data of poly-L-lactic acid (PLLA)/multi-walled carbon nanotube (MWCNT) nanocomposites, the electrical percolation threshold is lower than the EMI shielding percolation threshold. The predicted conductivity and EMI shielding curves are also in close agreement with experimental data. We further disclosed that the percolative behavior of EMI shielding in the overall CNT/polymer nanocomposite can be illustrated by the establishment of connective filler networks in the CNT-poor region. It is believed that the present research can provide directions for the design of CNT/polymer nanocomposites in the EMI shielding components.


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