The effect of carbonization/silver plating double modification on the thermal properties of PEG/wood-based composite phase change materials: experiments and molecular dynamics simulations

To overcome the bottleneck of single modification methods for composite phase change materials struggling to balance high thermal conductivity and high phase change enthalpy, this study employed poplar wood as the raw material to fabricate a wood-based porous carrier through a dual-modulation strategy involving carbonization and silver-plating. This modified carrier was then impregnated with polyethylene glycol phase change material to synthesize a shape-stable composite phase change material with integrated structure and function. A combined experimental and modeling approach was used to investigate the thermal properties and underlying mechanisms of the composite. Experimental results demonstrate that the silver-enhanced carbonized wood/polyethylene glycol composite phase change material achieved 93.2 % photothermal conversion efficiency and its thermal conductivity reached 0.632 W·m −1 ·K −1 , representing a 2.64-fold enhancement compared to pure polyethylene glycol. The material exhibited effective temperature control capability in electronic device thermal management scenarios and maintained stable phase change behavior over 100 heating–cooling cycles. Molecular dynamics simulations elucidated the synergistic mechanism between the silver nanoparticle-modified three-dimensional porous network and polyethylene glycol. Vibrational density of states spectra confirmed that enhanced interfacial phonon coupling reduced interfacial thermal resistance to 3.459 × 10 −9 m 2 ·K·W −1 , corresponding to a 56.23 % reduction relative to non-modified wood/polyethylene glycol composites. This work innovatively combines wood cell wall engineering with interfacial phonon engineering, revealing atomic-scale heat transfer mechanisms at the microscopic level. The integrated experimental and simulation approach provides valuable insights for developing wood-based multifunctional composite phase change materials.