Stretchable liquid metal electromagnetic interference shielding coating materials with superior effectiveness

Flexible electromagnetic interference (EMI) shielding materials typically exhibit poor stretchability due to the break of electronic transport, which makes shielding efficiency decrease sharply with discontinuous conductivity. This electric-mechanical contradiction is limiting for soft electronics a...

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Bibliographic Details
Published in:Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2019, Vol.7 (33), p.1331-1337
Main Authors: Zhang, Mingkuan, Zhang, Pengju, Wang, Qian, Li, Lei, Dong, Shijin, Liu, Jing, Rao, Wei
Format: Article
Language:English
Subjects:
Casting
Deformation
Electromagnetic shielding
Electron transport
Formability
Gallium oxides
Liquid metals
Mechanical properties
Newtonian fluids
Non Newtonian fluids
Stiffness
Stretchability
Substrates
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Summary:Flexible electromagnetic interference (EMI) shielding materials typically exhibit poor stretchability due to the break of electronic transport, which makes shielding efficiency decrease sharply with discontinuous conductivity. This electric-mechanical contradiction is limiting for soft electronics and other emerging applications that require materials with both high shielding performance and low mechanical stiffness. Here, this constraint is overcome with a liquid metal amalgam that exhibits superior metal conductivity and the capability to undergo large deformation (up to 300% strain). This amalgam is mainly composed of GaIn 24.5 , Ni particles and gallium oxide. A substrate decorated with this amalgam demonstrated excellent EMI shielding effectiveness of over 75 dB at frequencies of 100 kHz-18 GHz owing to its excellent conductivity; furthermore, this material can satisfy military shielding requirements (>60 dB) even at strains of up to 75%. Besides, this amalgam, as a non-Newtonian fluid, can facilely decorate various substrates with irregular shapes because it has good adhesion and superb flexibility. The exceptional combination of shielding performance and mechanical properties is enabled by large-scale deformability of the liquid metal to create a continuous conductive path, even under extreme stretching conditions. This material provides a brand new perspective for stretchable shielding applications. The GIN amalgam can easily decorate various substrates and provide sufficient shielding protect. Stretchable film decorated by GIN can satisfy military shielding requirements (>60 dB) even at strain up to 75%.
ISSN:2050-7526
2050-7534
DOI:10.1039/c9tc02887k