Scalable, large-size, and flexible transparent bamboo

Transparent wood (TW) has received extensive attention recently because of its excellent optical, mechanical, and thermal properties. However, the long growth cycle of timber and forbidden deforestation regulation limit the large-scale application. Bamboo has a much shorter growth cycle than wood, but its high density and lack of lateral cell tissues make it challenging to produce transparent products. Meanwhile, fabrication of large-size transparent bamboo (TB) remains a huge challenge because of the inherent features of irregular, hollow cylindrical shape with nodes, and big culm taper. In this work, the “alkali pretreatment-crosslinking-delignification” strategy was developed to fabricate the scalable, large-size, and flexible TB from the building block of sliced bamboo veneer (SBV). The optical transmittance and haze of the TB with a thickness of 1.0 mm were approximately 80 % and 72 %, respectively, and possessed the light modulation capability. The fabricated TB exhibited flexibility, and the tensile strength was 78.5 MPa, which was higher than all reported flexible TW. Besides, the TB exhibited a low thermal conductivity of 0.35 W m−1 k−1, which had an outstanding thermal insulation and indoor temperature regulation performance. More importantly, this study demonstrated the feasibility of successful preparation of large-size TB, which can promote its large-scale and industrial application. The TB with excellent overall performance holds great potential in engineering applications, especially for energy-efficient windows, light-tunable devices, flexible transparent materials, etc.