Enhancing effective anisotropic thermal conductivity and electromagnetic interference shielding via interface engineering of natural cellular channels in wood and liquid metal/cellulose aerogel

In this study, a continuous heat transfer network was constructed through interface engineering by performing surface functionalization on the surface of liquid metal (LM), on which alkoxy and carboxyl groups were introduced to facilitate strong interactions with the hydroxyl groups on cellulose aerogel (CA). This allowed LM to anchor onto the CA tube walls, which promoted the formation of a thermally conductive network. The thermal conductivity of CA filled with LM modified by thiomalic acid reached 7.421 W/(m·K) with a thermal conductivity anisotropy ratio of 23, which is 1.35 times higher than the unmodified LM-filled CA composite. The high heat transfer efficiency achieved in the composites in heat transfer experiments was further validated through finite element simulations, which showed that the construction of the LM thermal networks provided effective pathways for phonon transfer. Additionally, the prepared composites exhibited outstanding electromagnetic interference shielding performance with a shielding effectiveness of 32.11 dB corresponding to the blockage of 99.937% of the incoming radiation and a high conductivity of 25.64 S/m.