pH-responsive wood-based phase change material for thermal energy storage building material application

In this work, we prepared a composite phase change material by using wood as the matrix and polyethylene glycol (PEG) as phase change material (PCM). The composite realized a pH-induced function with the impregnation of litmus. As a hierarchical porous material, wood particle had a high PEG loading and solved the liquid leakage of PEG efficiently. Differential scanning calorimetry (DSC) measurement indicated that the freezing and melting enthalpy of the composite reached 102.2 J/g and 107.1 J/g, respectively. Thermal cycling tests, leakage testing and thermogravimetric analysis (TG) showed that the samples had excellent thermal reliability and stability. More importantly, the particle boards impregnated with litmus and PEG (LPB) has great pH induction ability, which could reflect the pH value through the color change. This provides the possibility of monitoring the rain pH value when it is used as building wall material. The outstanding pH response ability, excellent latent heat and thermal reliability of LPB suggest it had great potential in the application of building energy conservation, pH induction and temperature regulation.