A Flexible and Repairable Ultra-Broadband Electromagnetic Wave Absorber by Liquid-Liquid Phase Separation Strategy

Area of Science:

• Materials Science
• Electromagnetics
• Polymer Chemistry

Background:

• Ultra-broadband electromagnetic wave (EMW) absorption is crucial for electronic devices but often requires complex fabrication or harsh conditions.
• Existing absorbers face limitations in flexibility, repairability, and biocompatibility, hindering their use in advanced applications.

Purpose of the Study:

• To develop a simple, one-step method for creating flexible and repairable ultra-broadband EMW absorbers.
• To achieve a balance between impedance matching and attenuation for enhanced EMW absorption.
• To explore the potential of photopolymerization in ionic liquids for advanced material fabrication.

Main Methods:

• Utilized photopolymerization of a common monomer in ionic liquid.
• Leveraged liquid-liquid phase separation to create a polymer network with conductive nanochannels.
• Characterized the material's EMW absorption, mechanical properties, transparency, and repairability.

Main Results:

• Achieved the broadest effective absorption band (<-10 dB from 5 to 40 GHz) for single-layer absorbers.
• Demonstrated excellent mechanical properties: high fracture strength (≈8.2 MPa), fracture energy (≈774 kJ/m²), and stretchability (≈900% strain).
• Obtained high transparency (≈85%) and significant repairability of microwave absorption (≈97% repaired).

Conclusions:

• The proposed one-step method provides a general strategy for fabricating high-performance, flexible, and repairable ultra-broadband EMW absorbers.
• The developed material shows great promise for applications in biomedicine and flexible electronics.
• This work advances the field of flexible electromagnetic materials with a facile and effective fabrication technique.