Superstructure silver micro-tube composites for ultrahigh electromagnetic wave shielding

Absorption-dominant electromagnetic shielding materials can effectively reduce secondary pollution in the shielding process, and have greater significance in practical applications. Herein, silver (Ag) micro-tubes with superstructure, which were fabricated via using poly(lactic acid) (PLA) fibers as templates, were used to achieve the composites with ultrahigh, lightweight, and absorption-dominant electromagnetic shielding performance. The Ag nanoparticles were firstly deposited on the surface of PLA fibers by chemical reduction. The Ag micro-tubes were obtained by etching the PLA fibers in the core. The Ag nanoparticles were stuck together to form the Ag micro-tubes by polymer chains. The ultrahigh electromagnetic interference (EMI) shielding effectiveness (SE) of similar to 110 dB was found in the Ag micro-tubes composed with polydimethylsiloxane or PLA with 1.5 mm in thickness. Due to the micro-tube structure, the composites containing with Ag micro-tubes exhibited absorption dominant shielding mechanism and low density. The absorption coefficient (A) value could reach 0.79 in the composites with Ag micro-tubes. The ultrahigh EMI SE performance and absorption dominant shielding mechanism of the composites was ascribed to the superstructure of the Ag micro-tubes which could efficiently create surface plasmon resonance, electronic vibration, interfacial polarization, capacitance effect and conductive loss. The work provides a new idea for preparing ultrahigh electromagnetic shielding materials with high absorption and low density.

Automated summary

This study focuses on the preparation of absorption-dominant electromagnetic shielding materials using silver (Ag) micro-tubes with superstructure fabricated via deposition of Ag nanoparticles on poly(lactic acid) (PLA) fibers. The composites show ultrahigh electromagnetic interference (EMI) shielding effectiveness and low density, attributed to the absorption dominant shielding mechanism of the Ag micro-tubes. The superstructure of the Ag micro-tubes creates efficient surface plasmon resonance, electronic vibration, interfacial polarization, capacitance effect, and conductive loss, contributing to the high absorption and low density of the materials.