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Updated: Aug 15, 2026
Towards Biomimicking Wood: Fabricated Free-standing Films of Nanocellulose, Lignin, and a Synthetic Polycation
Published on: June 17, 2014
Cellulose nanofiber based films with oriented, spiky ball-chain and cocoa-tree gradient heterostructures for
Gengmei Liu1, Jinbao Li1, Dingwen Yin1
1College of Bioresources Chemical & Materials Engineering, Shaanxi University of Science & Technology, Xi'an, Shaanxi, 710021, China.
Abstract:
The proliferation of 5G technology has intensified electromagnetic pollution, necessitating the development of advanced shielding materials with exceptional attenuation and low reflection. Harnessing the abundance of cellulose nanofiber (CNF), this study presents a hierarchically designed trilayer composite film with an inverse gradient structure, featuring a descending magnetic permeability gradient and an ascending electrical conductivity gradient. The architecture comprises: a magnetic field oriented Co-Fe NPs top layer fixed by CNF@PDA, maximizing eddy current and hysteresis losses through aligned nanostructures; an intermediate spiky ball-chain-like CNF-Ni layer enhancing polarization and scattering losses via multiscale interfaces; and a bio-inspired cocoa-tree-like CNF/AgNWs/SiO2@PDA base layer establishing an interconnected conductive network for resistor-capacitor coupled loss. This meticulously engineered transition from strong magnetic to dominant dielectric dissipation achieves unprecedented impedance matching, resulting in an exceptional shielding effectiveness of 98.25 dB in the X-band while maintaining an ultralow reflection loss of 6.08 dB. The CNF-based composite further demonstrates remarkable thermal stability, excellent mechanical flexibility, and ultrafast strain response, representing a significant advancement in multifunctional electromagnetic shielding materials for next-generation communication systems.
