Stretchable microwave absorbing and electromagnetic interference shielding foam with hierarchical buckling induced by solvent swelling

Huang, Kun; Chen, Mengmeng; He, Gang; Hu, Xiaoyu; He, Wenqian; Zhou, Xiang; Huang, Yi; Liu, Zunfeng

doi:10.1016/j.carbon.2019.10.059

Cited by 85 publications

(45 citation statements)

References 55 publications

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“…Though research and development into microwave absorbing materials [ 2–14 ] is growing exponentially, [ 15 ] the current R&D pipeline has yet to see the implementation of data‐driven methods into the materials development cycle. Current research involves rigorous materials development though complex nanostructure formulation and composite development.…”

Section: Figurementioning

confidence: 99%

Obtaining Strong, Broadband Microwave Absorption of Polyaniline Through Data‐Driven Materials Discovery

Green

Tran

Chen

2020

Adv Materials Inter

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materials development methods do not guarantee results. Yet, the continued development of microwave absorbing materials is imperative. These materials are highly utilized in the defense [16-22] and telecommunications industries, [18,23-27] as means for reducing radar cross sections for stealth technology, [28,29] and providing electromagnetic interference shielding for the information processing and transport capabilities in electronic devices. The progression of research and development in the field of MAMs continues to accelerate, and researchers are in need of new methods for materials development and analysis. One of the most common components integrated into materials systems for microwave absorption is polyaniline. [30-36] This polymer, particularly the protonated Emeraldine Salt variation due to its high conductivity, is a popular material for MAM research and development due the strong dielectric response it demonstrates when irradiated with GHz-range electromagnetic energy. [15] For example, Liu et al. embedded a graphene-polyaniline matrix with nickel ferrite in an attempt to synergistically couple the magnetic properties of the ferrite with the dielectric nature of the matrix. This coupling resulted in a strong microwave interaction and reflection loss of −50.5 dB at 12.5 GHz, with an effective bandwidth of 5.3 GHz. [30] Wang et al. took a similar approach, imbedding a nickel-zinc ferrite into a polyaniline matrix, with a similar goal of coupling the strong dielectric action of the polyaniline material with a magnetic material. The maximal reflection loss realized by these efforts was −41 dB at 12.8 GHz and a 5 GHz effective bandwidth with a material thickness of 2.6 mm. [31] In this study, we demonstrate for the first time a data-driven process for optimizing the microwave absorbing properties of polyaniline. The final reflection loss is maximally reported as −88.54 dB with (f, d) coordinates of (7.0 GHz, 3.8 mm) 5.5 GHz with a 2.1 mm thickness. These results are record-setting for polyaniline-based materials, and the methods used to achieve these experimentally-validated results are thought to be scalable and applicable to the type of research methodologies prevalent in MAM development. As such, this type of data-driven optimization has the potential to revolutionize materials R&D for microwave absorption. The polyaniline materials were synthesized according to standard literature procedures [37] and characterized via X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and Microwave absorbing materials (MAMs) are highly utilized in the defense and telecommunications industries, as means for reducing radar cross sections for stealth technology, and providing electromagnetic interference shielding for the information processing and transport capabilities in electronic devices. Polyaniline materials have attracted enormous attention in the field of MAM development due to their strong dielectric properties. In this manuscript, the strong dielectric action of polyaniline is utilized to demonstrate...

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Section: Figurementioning

confidence: 99%

Obtaining Strong, Broadband Microwave Absorption of Polyaniline Through Data‐Driven Materials Discovery

Green

Tran

Chen

2020

Adv Materials Inter

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“…The EMI shielding stability of the LM/PDMS lattice composites was compared with other stretchable EMI shielding materials made by various techniques (Figure 4d and Figure S7, Supporting Information). In comparison, the composites fabricated by dispersing conductive fillers into the polymer matrix (blue symbols) generally exhibit significantly declined EMI SE at stretching, [ 48–51 ] although great efforts have been made to improve the dispersion state and utilize high‐quality fillers and elastomer matrixes. The different results are because the conductive networks of those composites constructed by percolated solid fillers could be easily changed with the deformed matrix, which makes the conductive paths vulnerable to external loadings and thus exhibits unstable EMI SE.…”

Section: Resultsmentioning

confidence: 99%

Rational Assembly of Liquid Metal/Elastomer Lattice Conductors for High‐Performance and Strain‐Invariant Stretchable Electronics

Wang

Xia

Zhu

et al. 2021

Adv Funct Materials

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Highly stretchable and conductive composites have gained tremendous research interests due to the imperative demands in the fields of stretchable electronics and soft robotics. However, it is challenging to maintain the original performance of the composites under complex external deformations. Here, a one‐step dual‐material 3D printing technique is developed to rationally assemble liquid metal (LM) into an elastomer lattice. The 3D interconnected and deformable liquid conductive network is supported by a highly ordered and robust polydimethylsiloxane lattice skeleton, yielding the resultant composites high electrical conductivity (1.98 × 106 S m−1), stretchability (180%), and electromagnetic interference (EMI) shielding effectiveness (72 dB). Unlike those composites with dispersed fillers, the LM/elastomer lattice composites deliver negligible electromechanical coupling, showing a negative resistance change of only −2% at a large tensile strain of 100%. The composites also exhibit strain‐invariant EMI shielding performance in a strain range of 0–100%, and present exceptional stability over 1000 rigorous cycles of stretching and releasing. The applications of the composites in flexible display circuits, microwave shielding layer, and EMI shields in wireless power transmission systems are demonstrated. The current findings suggest an effective strategy for fabricating LM‐based composites with precisely controlled and unprecedented multi‐functionality.

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“…Fabricating process of the CF/PU conductive film (a), digital photograph of the prepared ZnO-g-CF/PU film (b), tensile curves of the CF/PU composite with different components (c), corresponding tensile strength and elongation at break (d), conductivity–strain relationship of the conductive films with different components (e), corresponding initial conductivity and conductivity at 100% strain (f); and comparison of relative conductivity (σ: conductivity; σ 0 : initial conductivity) and stretchablility in other reports: CNTs/PDMS, CNTs/PU/Ecoflex, Ag NWs/TPU, Ag@Au NWs/PDMS, Ag NWs/PU, Au/Ni@GE/PDMS, CNTs/GO/PDMS, rGO/PDMS, CNTs/GE/PDMS, CNTs/PDMS, Ag NWs/PDMS, , Au/PDMS, , Ag/PDMS, and liquid metal/PU (g).…”

Section: Resultsmentioning

confidence: 99%

“…When the mixed CF/ ZnO hybrid fillers were introduced into the PU matrix at the same total mass loading, the medium strength (4.96 MPa) implied that the superior mechanical property of ZnO-g-CF/ PU composite, in essence, originated from positive contribution of the unique interface rather than the synergistic enhancement effect of CF and ZnO. It is worth noting that although the mechanical enhancements were accompanied by 42 CNTs/PU/Ecoflex, 43 Ag NWs/ TPU, 44 Ag@Au NWs/PDMS, 45 Ag NWs/PU, 46 Au/Ni@GE/PDMS, 47 CNTs/GO/PDMS, 48 rGO/PDMS, 49 CNTs/GE/PDMS, 50 CNTs/ PDMS, 51 Ag NWs/PDMS, 52,53 Au/PDMS, 54,55 Ag/PDMS, 56 and liquid metal/PU 57 (g). a clear reduction in the elongation at break, the ZnO-g-CF/PU composite still tolerated a strain up to 216%, which was high enough to satisfy the application of the wearable electronics (tensile strain of larger than 50%).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Highly Stretchable and Conductive Carbon Fiber/Polyurethane Conductive Films Featuring Interlocking Interfaces

Yang

Nie

et al. 2021

ACS Appl. Mater. Interfaces

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Stretchable conductors are essential assembly units of next-generation flexible electronics, requiring excellent conductivity and stretchability simultaneously. However, poor interfacial adhesion between conductive fillers and polymer matrixes often triggers the relative slippage and dislocation of the conductive network, deteriorating the final conductivity. Herein, we constructed interlocking interfaces in a polyurethane (PU) conductive composite by introducing brush-like carbon fibers (CFs) with laterally grown zinc oxide nanowires (ZnO NWs). The ZnO NW-enabled construction of the functional interfaces integrated the CFs tightly with the polymer matrix to greatly improve the interfacial adhesion and suppress the sliding displacement of conductive fillers upon external load, contributing to excellent mechanical strength and conductive stability. Specifically, the combination of high mechanical strength (7.19 MPa) and stable conductivity (26.3 S/m under 100% strain, approaching 30 S/m of the initial conductivity) was demonstrated for the brushlike CF/PU film. Finally, the application potential of the novel stretchable conductor as a thermal therapy unit and connecting wire in a flexible circuit was explored successfully under complex dynamic deformations. Accordingly, this inspiring result creatively combines the interface geometry with conductive stability, and offers a facile and effective route to prepare excellent stretchable conductors, which can be easily applied to other conductive composites.

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Stretchable microwave absorbing and electromagnetic interference shielding foam with hierarchical buckling induced by solvent swelling

Cited by 85 publications

References 55 publications

Obtaining Strong, Broadband Microwave Absorption of Polyaniline Through Data‐Driven Materials Discovery

Obtaining Strong, Broadband Microwave Absorption of Polyaniline Through Data‐Driven Materials Discovery

Rational Assembly of Liquid Metal/Elastomer Lattice Conductors for High‐Performance and Strain‐Invariant Stretchable Electronics

Highly Stretchable and Conductive Carbon Fiber/Polyurethane Conductive Films Featuring Interlocking Interfaces

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