Photochromic transparent bamboo composite with excellent optical and thermal management for smart window applications

In the face of the frequent occurrence of many global climate anomalies in recent years, the concept of green and sustainable development has driven a growing interest among researchers in the development and utilization of renewable biomass resources. Transparent wood (TW) has become a hot research topic due to its transparency, sustainability, and multi-functionality. However, the long growth period of wood and the shortage of wood resources have hindered the large-scale application of TW. Although bamboo has also been shown to have the capability to prepare transparent materials, the preparation of transparent bamboo (TB) with advanced functionality and large dimensions has always been a challenge. In this study, a straightforward but efficient method for preparing photochromic transparent bamboo (PTB) with enlarged dimensions (100 mm × 100 mm × 0.9 mm) is introduced. The method involves pre-crosslinking the delignification of sliced bamboo veneer (SBV) and impregnating delignified bamboo (DB) substrates with epoxy resin mixed with photochromic pigments (PC). The PTB composites that emerged displayed impressive characteristics such as excellent optical performance, rapid photochromic response, thermal insulation behavior, and robustness. The PTB's excellent overall performance is promising to be applied in some high-end fields, such as smart windows, information storage, smart decorative materials, etc.