Encapsulation of thermochromic tetradecyl myristate/methyl red composite via full poplar-based cellulose/lignin/SiO2 framework for preparation of thermochromic wood with thermal response and storage.

ABSTRACT

Thermochromic wood (TW), a smart material that can respond to temperature changes and store thermal energy, holds broad potential for application in the construction industry. This study fabricated thermochromic poplar (TP) by encapsulating a thermochromic phase change material (TPCM), consisting of tetradecyl myristate and methyl red, within a full poplar-based cellulose/lignin/SiO2 framework. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses indicate that the poplar matrix and the incorporated SiO2 formed an integrated cellulose/lignin/SiO2 framework, which encapsulated the TPCM within the poplar ducts. The TP exhibits a color change from light purple to dark purple within the temperature range of 30-48 °C, with a pronounced shift at approximately 42 °C, correlating with the sensation of scalding. Thus, TP-based products can alert users to the risk of scalding through a noticeable color change. The full poplar-based framework mitigates the impact of ultraviolet (UV) radiation on the TP and prevents the loss of TPCM during thermal processing. The mechanical properties of TP are enhanced to a strength grade comparable to that of Manchurian ash wood, making it suitable for load-bearing components in wooden structures. Additionally, the average temperature of TP is around 10 °C higher than that of untreated poplar within 25 min after the same thermal treatment. Consequently, TP can serve as a building material with capabilities for temperature response, thermal energy storage, and structural load-bearing.