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

Abstract

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.

Review on engineering designing of electromagnetic interference shielding materials using additive manufacturing

“…Due to their compatibility characteristics with the fusion and extrusion process of 3D printing and inherent properties required for shielding electromagnetic waves, the specific type of raw materials can be used to fabricate EMI shielding material using unique 3D printing processing. The different raw materials like PLA, [43][44][45]51,52] poly (3,4-ethylene dioxythiophene): poly (styrene sulfonic acid), [48] polypropylene random copolymer, [50] graphene nanofilms, [46] CNT, MWCNT, and CB has been used for developing EMI shielding material as shown in Figure 14 given below.…”

“…Also, a few modifications can be done to prepare composites and substrates to attain the required EMI SE. [48] In another study, Yan Wang et al, 2020, reported 3D printed scaffolds of PLA as a matrix and CNT as fillers for electrical conductivity were used to fabricate the material for EMI shielding applications. Materials used in the fabrication process were PLA, CNT, and CTAB (cetyltrimethylammonium).…”

“…Also, a few modifications can be done to prepare composites and substrates to attain the required EMI SE. [ 48 ]…”

Progress in polymers and polymer composites used as efficient materials for EMI shielding

“…Dielectric measurements of the PANI/PS/MWCNT composites showed a one order of magnitude increase in the real part of the electrical permittivity when compared to PS/MWCNT composites, which enables them to be used for charge storage purposes. Zakar et al 101 investigated the cumulative effects of layering a conductive polymer composite containing 2 wt% of MWCNT in PEDOT:PSS on a Mylar substrate for application in EMI shielding. The optical transmittance of the spin-coated composite layers was 90%, 45%, and 20% with a thickness of 0.05 μm, 0.15 μm, and 0.45 μm, respectively.…”

“…The incorporation of AgNW imparted the functionalized PPy with tunable electrical conductivity and improved EMI shielding efficiency. By increasing content Zakar et al[101] investigated the cumulative effects of layering a conductive polymer composite containing 2 wt. % of MWCNT in PEDOT:PSS on a Mylar substrate for application in EMI shielding.…”