Liquid metal/wood-based phase change materials with anisotropic and high thermal conductivity for targeted thermotherapy

Hot/cold therapy is a therapeutic method that can promote blood circulation and alleviate pain. However, thermal management materials with low efficiency and non-targeted limit their thermotherapy application. Herein, metallic wood (Ga/DW) has been developed with anisotropic and high thermal conductivity, in which liquid metal gallium (Ga) is used as the phase change material filling in the anisotropic wood channels. As a phase change material, Ga exhibits a low melting point, close to human body temperature, and high thermal conductivity. Wood's unique anisotropic porous structure endows metallic wood with anisotropic thermal conductivity and form stability, serving as effective supporting materials. The anisotropic thermal conductivity ratio (kappa & Vert;/kappa perpendicular to) of metallic wood is 5.92, which can precisely locate the heat management spot and reduce unnecessary heat diffusion for long-term constant temperature. The high axial thermal conductivity (0.378 W/m & sdot;K), enthalpy of fusion (64.66 J/g) and excellent from-stable properties further indicate that metallic wood has good potential to be used for personal thermal management and thermotherapy. This anisotropic thermal conductivity strategy may open a promising avenue for studying targeted thermotherapy.