Two thermochromic laminated veneer cellulose-based alizarin/stearic acid/nano‑silicon dioxide/hexagonal boron nitride composites encapsulated with xanthan gum and wood wax oil films, that have excellent temperature-responsive and thermal-storing capabilities

Thermochromic wood-based phase change material (TWPCM) is a temperature-responsive, smart material that actively manages thermal energy in response to ambient temperature fluctuations. The material has become a central focus in research on thermal energy storage and temperature sensing in recent years. A key research direction is the incorporation of delignified veneer impregnated with thermochromic phase change material (TPCM) into a multi-layered structure to enhance the thermal energy storage capacity of TWPCM. This study fabricated two thermochromic laminated veneer cellulose-based alizarin/stearic acid/nano‑silicon dioxide/hexagonal boron nitride composites encapsulated with xanthan gum and wood wax oil films, designated as TWPCM1-XW and TWPCM2-XW. Herein, a TPCM with superior latent heat value (215.9 J/g) was fabricated by compositing alizarin and stearic acid. TWPCM1-XW and TWPCM2-XW can obviously change color within a temperature range of 52–74 °C and revert to primary color at temperatures below 45 °C within 60 min, their latent heat values can reach 133.8 J/g and 163.4 J/g. Therefore, the resulting composites exhibit superior temperature-responsive and thermal-storing capabilities. Moreover, the materials demonstrate outstanding long-term applicability and stability in their capabilities. Additionally, the chemical structures of the synthesized materials were elucidated, and their thermochromic and thermal-storing mechanisms were explained for developing the smart material.