The growing use of wireless electronics and high-frequency technologies has increased the demand for materials that can simultaneously manage electromagnetic interference, heat and fire. However, many high-performance porous materials depend on freeze-drying or solvent-exchange processes, which increase energy consumption and complicate large-scale manufacturing. The new work addresses this processing challenge by using bamboo fiber as the structural framework and combining it with TEMPO-oxidized cellulose nanofibrils and multiwalled carbon nanotubes.
The preparation relies on a multiscale assembly strategy. TOCNFs help disperse MWCNTs throughout the bamboo fiber network, while hydrogen bonding, fiber entanglement and Zn2+-mediated crosslinking reinforce the porous framework. Ice templating is used to establish the cellular structure, after which aniline is polymerized in situ to form a polyaniline network. This interconnected structure allows the resulting foam to retain its shape during ambient drying, avoiding the severe collapse normally caused by capillary forces during water evaporation. The authors report that the energy cost of ambient drying was only 1.23% of that required for freeze-drying.
The optimized Zn-P3M4BC1 foam showed an electrical conductivity of 101.7 S/m and an EMI shielding effectiveness of 61.56 dB in the X-band. Its lightweight architecture also delivered an SSE/d value of 2,375.2 dB cm2/g. Beyond electromagnetic protection, the foam exhibited a limiting oxygen index of 56.8% and a peak heat release rate of only 20.71 W/g. Its thermal conductivity remained as low as 0.085 W/(m·K).
The conductive network further enabled Joule heating. Under an applied voltage of 5 V, the foam reached approximately 166.8 °C and maintained a stable temperature of 167 ± 2 °C for 900 seconds. Demonstrations also showed that the material could mask the infrared signatures of heated objects and provide electrically assisted deicing. The study therefore presents ambient drying as a practical route toward lightweight cellulose foams that combine electromagnetic shielding with thermal protection and active thermal functions.
See the article:
DOI
https://doi.org/10.1016/j.jobab.2026.100299
Original Source URL
https://www.sciencedirect.com/science/article/pii/S236996982600071
Journal
Journal of Bioresources and Bioproducts
