Reversible thermochromic transparent bamboo for dynamically adaptive smart windows

The development of energy-saving functional materials plays a crucial role in the field of smart windows. Transparent bamboo is an emerging sustainable alternative to glass. However, the use of transparent bamboo in combination with organic thermochromic materials has not yet been thoroughly studied. In this study, reversible thermochromic transparent bamboo with dynamically temperature-adaptive functions was developed by incorporating thermochromic microcapsule powder. Reversible thermochromic transparent bamboo is colorless and has high transmittance at low temperatures, whereas it is purple with low transmittance at high temperatures providing a visually cool emotional impression. With the increase in thermochromic powder addition, the transmittance of thermochromic transparent bamboo decreased and the haze increased. When the amount of thermochromic powder was 1 wt % of the resin mass, the highest transmittance in thermochromic bamboo was 79.27 % for colorless and 63.67 % for colored. The highest tensile strength (77.79 MPa) and lowest thermal conductivity (0.225 W m-1 K-1) were obtained when the amount of powder was 3 wt %. Thermochromic transparent bamboo has excellent potential for smart window applications and its impressive haze and light absorption properties may also allow it to be used as a solar energy storage material.