Scientists in China have transformed bamboo into a contender against glass, a surprising development in the materials world. This bamboo variant offers transparency, fire and water resistance, and smoke suppression.
Traditionally, silica glass, derived from sand, has been the preferred choice for transparent and sturdy structures such as windows. However, its sustainability is questionable, and it tends to be heavy and brittle.
Transparent wood has emerged as a competitor to glass in recent years. By chemically removing lignin from wood fibers and treating the material with substances like plexiglass or epoxy, researchers have produced a renewable, transparent, and robust alternative to glass, with superior thermal insulation and reduced weight.
In light of these advancements, challenges like wood’s flammability and sluggish replenishment rates come to the fore. Thus, researchers at the Central South University of Forestry and Technology (CSUFT) shifted their focus to bamboo to tackle these concerns.
“Bamboo, often referred to as ‘the second forest,’ boasts a fast growth and regeneration rate, allowing it to reach maturity and be utilized as a building material within four to seven years of growth,” said Caichao Wan, corresponding author of the study. “With an output four times higher than wood per acre, bamboo is recognized for its exceptional efficiency.”
After removing lignin, the bamboo is infused with an inorganic liquid sodium silicate to alter light refraction, resulting in transparency. Additional treatments make the material hydrophobic, fire-resistant, and capable of blocking smoke and carbon monoxide. The resulting structure consists of three layers: silane on top, silicon dioxide in the middle, and sodium silicate at the bottom.
Transparent bamboo exhibits a light transmittance of 71.6% and impressive mechanical properties, with bending and tensile moduli of 7.6 GPa and 6.7 GPa, respectively.
Furthermore, transparent bamboo demonstrates potential beyond building materials. When used as a substrate for perovskite solar cells, it enhances light management and increases power conversion efficiency by 15.29%.
“In the future research, we will focus on the large-scale fabrication and multi-functionalization of this transparent bamboo,” said Wan.
