When it comes to transparent building materials, the likes of construction experts, electronic manufacturers, and aerospace professionals typically turn to glass as their go-to choice. Now an unexpected contender has emerged as a more sustainable option: bamboo. While it sounds bizarre in theory, it actually presents practical solutions that surpass those of glass.
Why traditional glass works—and also why it doesn’t
Whether it’s a window, a pair of spectacles, or a screen protector for your mobile phone, traditional silica glass—made from sand—has been the primary building material of choice due to its clarity, malleability, and durability.
On the other hand, glass does have its drawbacks. It is susceptible to breakage when under significant pressure, is not fire-resistant, and cannot completely suppress smoke. Additionally, without proper hydrophobic coating, glass can absorb water, which can result in moisture accumulation and deterioration over time.
In a bid to seek a stronger, renewable alternative, researchers at the Central South University of Forestry and Technology (CSUFT) in Changsha, China, turned to bamboo—an ancient building material dating back 5000 years—to create a new form of transparent glass.
When it comes to wood, bamboo is a cut above the rest
It’s not the first time that scientists have used a renewable source like wood to develop glass. The process involves extracting the lignin from the fibers and subsequently treating the remaining material with polymers such as epoxy or plexiglass. This renders the material transparent and robust, much more so than traditional glass.
Unfortunately, wood is far more flammable than glass. The high demand for wood also means that it takes far longer for forests to regenerate.
Drawing inspiration from these previous experiments, the CSUFT team—led by professors Caichao Wan and Yiqiang Wu—used a similar process on bamboo. After removing the lignin and treating the leftover material with an inorganic liquid sodium silicate, they then applied a hydrophobic coating.
The end result is a transparent, three-layered bamboo structure, one that has a light transmission of 71.6%, is water- and fireproof, and can block smoke and carbon monoxide. Where mechanical capabilities are concerned, it possesses a bending module of 7.6 GPa as well as a traction module of 6.7 GPa.
It’s crystal clear: Transparent bamboo is nature’s answer to long-term sustainability
As a renewable resource, says Professor Wan, bamboo grows rapidly and can be harvested without damaging ecosystems.
“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,” he explained. “With an output four times higher than wood per acre, bamboo is recognized for its exceptional efficiency.”
Compared to traditional glass, the unique properties of transparent bamboo make it ideal for “high light transmission and a high haze factor, allowing privacy and facilitating the entry of natural light into the interior.” It also holds promise as a component in solar technology, in that it can act as a light management layer for perovskite solar cells, thereby boosting their conversion efficiency by 15.29%.
Professor Wan says that the CSUFT team plans to focus on “large-scale fabrication and multi-functionalization” of transparent bamboo as they continue their research.
For now, the results they have yielded are indicative of bamboo’s prospects as a viable alternative to glass in real-world applications. Perhaps in the near future, various industries will begin to recognize the benefits of this innovative material and transition to using it instead of traditional glass. Until then, bamboo represents a promising step forward in the journey for sustainable, transparent building materials.