Tag Archives: Qiliang Fu

Cellulose aerogels for new wood-based composites

‘Frozen smoke’ or ‘solid smoke’ as it’s sometimes described, aerogel fascinates scientists.The latest on cellulose aerogels derived from wood is the focus for a February 14, 2018 Nanowerk Sportlight article by Michael Berger (Note: Links have been removed),

Aerogels, sometimes called frozen smoke, are nanoscale foams: solid materials whose sponge-like structure is riddled by pores as small as nanometers across. They can be made from different materials, for instance silicon.

Aerogels are among the lightest solid substances in the world yet flexible, extremely strong and water repellent, which makes them very interesting materials for engineers.

Cellulose aerogels, made from nanofibrils found in plants, have several unique features, one of which is super high oil absorption capacity that is several times higher than commercial sorbents available in the market.

“Encouraged from our previous work on transparent wood (“Transparent wood for functional and structural applications”; “Optically Transparent Wood from a Nanoporous Cellulosic Template: Combining Functional and Structural Performance”; “Nanostructured Wood Hybrids for Fire-Retardancy Prepared by Clay Impregnation into the Cell Wall”), we started to develop porous wood/epoxy biocomposite materials, which preserves the original hierarchical and porous structure of wood,” Qi Zhou, an associate professor in the Department of Chemistry at KTH Royal Institute of Technology, tells Nanowerk.

“Our strategy is different from traditional wood modification methods,” explains Zhou. “It involves two steps, a simple chemical treatment to remove the lignin (delignification) at first, then back infiltration of the wood cell wall with epoxy, leaving the lumen (a void space) open. In traditional wood polymer composites, both the cell wall and cell lumen are filled with polymer.”

The scientists don’t seem to have any particular applications in mind but they are hopeful that new materials will inspire new uses. Here’s a link to and a citation for Zhou’s latest paper,

Wood Nanotechnology for Strong, Mesoporous, and Hydrophobic Biocomposites for Selective Separation of Oil/Water Mixtures by Qiliang Fu, Farhan Ansari, Qi Zhou, and Lars A. Berglund. ACS Nano, Article ASAP DOI: 10.1021/acsnano.8b00005 Publication Date (Web): February 7, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

Transparent wood instead of glass for window panes?

The transparent wood is made by removing the lignin in the wood veneer. (Photo: Peter Larsson

The transparent wood is made by removing the lignin in the wood veneer. (Photo: Peter Larsson

Not quite ready as a replacement for some types of glass window panes, nonetheless, transparent (more like translucent) wood is an impressive achievement. According to a March 30, 2016 news item on ScienceDaily size is what makes this piece of transparent wood newsworthy,

Windows and solar panels in the future could be made from one of the best — and cheapest — construction materials known: wood. Researchers at Stockholm’s KTH Royal Institute of Technology [Sweden] have developed a new transparent wood material that’s suitable for mass production.

Lars Berglund, a professor at Wallenberg Wood Science Center at KTH, says that while optically transparent wood has been developed for microscopic samples in the study of wood anatomy, the KTH project introduces a way to use the material on a large scale. …

A March 31 (?), 2016 KTH Institute of Technology press release, which originated the news item, provides more detail,

“Transparent wood is a good material for solar cells, since it’s a low-cost, readily available and renewable resource,” Berglund says. “This becomes particularly important in covering large surfaces with solar cells.”

Berglund says transparent wood panels can also be used for windows, and semitransparent facades, when the idea is to let light in but maintain privacy.

The optically transparent wood is a type of wood veneer in which the lignin, a component of the cell walls, is removed chemically.

“When the lignin is removed, the wood becomes beautifully white. But because wood isn’t not naturally transparent, we achieve that effect with some nanoscale tailoring,” he says.

The white porous veneer substrate is impregnated with a transparent polymer and the optical properties of the two are then matched, he says.

“No one has previously considered the possibility of creating larger transparent structures for use as solar cells and in buildings,” he says

Among the work to be done next is enhancing the transparency of the material and scaling up the manufacturing process, Berglund says.

“We also intend to work further with different types of wood,” he adds.

“Wood is by far the most used bio-based material in buildings. It’s attractive that the material comes from renewable sources. It also offers excellent mechanical properties, including strength, toughness, low density and low thermal conductivity.”

The American Chemical Society has a March 30, 2016 news release about the KTH achievement on EurekAlert  highlighting another potential use for transparent wood,

When it comes to indoor lighting, nothing beats the sun’s rays streaming in through windows. Soon, that natural light could be shining through walls, too. Scientists have developed transparent wood that could be used in building materials and could help home and building owners save money on their artificial lighting costs. …

Homeowners often search for ways to brighten up their living space. They opt for light-colored paints, mirrors and lots of lamps and ceiling lights. But if the walls themselves were transparent, this would reduce the need for artificial lighting — and the associated energy costs. Recent work on making transparent paper from wood has led to the potential for making similar but stronger materials. Lars Berglund and colleagues wanted to pursue this possibility.

Here’s a link to and a citation for the paper,

Optically Transparent Wood from a Nanoporous Cellulosic Template: Combining Functional and Structural Performance by Yuanyuan Li, Qiliang Fu, Shun Yu, Min Yan, and Lars Berglund. Biomacromolecules, Article ASAP DOI: 10.1021/acs.biomac.6b00145 Publication Date (Web): March 4, 2016

Copyright © 2016 American Chemical Society

This paper appears to be open access.