Category Archives: forestry

Wood pulp and pomegranate peels as clothing

Lilly Smith’s Sept. 11, 2020 article for Fast Company profiles a new article of clothing from Volllebak (first mentioned here in a March 11, 2019 posting titled: It’s a very ‘carbony’ time: graphene jacket, graphene-skinned airplane, and schwarzite),

The Vollebak hoodie is made out of sustainably sourced eucalyptus and beech trees. The wood pulp from the trees is then turned into a fiber through a closed-loop production process (99% of the water and solvent used to turn pulp into fiber is recycled and reused). The fiber is then woven into the fabric you pull over your head.

The hoodie is a light green because it’s dyed with pomegranate peels, which typically are thrown out. The Vollebak team went with pomegranate as the natural dye for the hoodie for two reasons: It’s high in a biomolecule called tannin, which makes it easy to extract natural dye, and the fruit can withstand a range of climates (it loves heat but can tolerate temperatures as low as 10 degrees). Given that the material is “robust enough to survive our planet’s unpredictable future,” according to Vollebak cofounder Nick Tidball, it’s likely to remain a reliable part of the company’s supply chain even as global warming causes more extreme weather patterns.

… the hoodie won’t degrade from normal wear and tear—it needs fungus, bacteria, and heat in order to biodegrade (sweat doesn’t count). It will take about 8 weeks to decompose if buried in compost, and up to 12 if buried in the ground—the hotter the conditions, the faster it breaks down. “Every element is made from organic matter and left in its raw state,” says Steve Tidball, Vollebak’s other cofounder (and Nick’s twin brother). “There’s no ink or chemicals to leach into the soil. Just plants and pomegranate dye, which are organic matter. So when it disappears in 12 weeks, nothing is left behind.”

The article hosts a picture of the hoodie as does Vollebak website’s Product, Plant and Pomegranate Hoodie webpage,

Plant and Pomegranate Hoodie. Built from eucalyptus trees and dyed in a giant vat of fruit. The waiting list is now open.

5,000 years ago our ancestors made their clothes from nature, using grass, tree bark, animal skins and plants. We need to get back to the point where you could throw your clothes away in a forest and nature would take care of the rest. The Plant and Pomegranate Hoodie feels like a normal hoodie, looks like a normal hoodie, and lasts as long as a normal hoodie. The thing that makes it different is simply the way it starts and ends its life. All the materials we’ve used were grown in nature. Each hoodie is made from eucalyptus trees from sustainably managed forests before being submerged in a giant vat of pomegranate dye to give it its colour. As it’s made entirely from plants, the hoodie is fully biodegradable and compostable. When you decide your hoodie has reached the end of its life – whether that’s in 3 years’ time or 30 – you can put it out with the compost or bury it in your garden. Because the hoodie that starts its life in nature is designed to end up there too. Launching September 2020, the waiting list is now open.

Not much information, eh? I found the same dearth of detail the last time I looked for more technical information about a Vollebak product (their graphene jacket).

As for composting or burying the hoodies, how does that work? I live in an apartment building; I don’t think composting is allowed in my apartment and the building owners will likely get upset if I start digging holes in the front yard. There is a park nearby but it is city property and I’m pretty sure that digging into it to bury a hoodie will turn out to be illegal.

There is a recycling bin for organics but I don’t know if the businesses tasked with picking up the organic refuse and dealing with it will be familiar with biodegradable hoodies and I ‘m not sure hoodie disposal in the organics would be allowed by the city, which oversees the recycling programme.

These are not insurmountable problems but if people want to be mindful about their purchases and future disposal of said purchases, research may be needed.

Glass-like wood windows protect against UV rays and insulate heat

Engineers at the University of Maryland designed a transparent ceiling made of wood that highlights the natural woodgrain pattern. Credit: A. James Clark School of Engineering, University of Maryland [downloaded from https://phys.org/news/2020-08-glass-like-wood-insulates-tough-blocks.html]

An August 7, 2020 news item by Martha Hell on phys.org announces the latest research (links to previous posts about this research at the end of this post) on ‘transparent’ wood from the University of Maryland,

Need light but want privacy? A new type of wood that’s transparent, tough, and beautiful could be the solution. This nature-inspired building material allows light to come through (at about 80%) to fill the room but the material itself is naturally hazy (93%), preventing others from seeing inside.

An August 16, 2020 University of Maryland news release (also on EurekAlert) describes the work in more detail,

Engineers at the A. James Clark School of Engineering at the University of Maryland (UMD) demonstrate in a new study that windows made of transparent wood could provide more even and consistent natural lighting and better energy efficiency than glass

In a paper just published [July 31, 20202] in the peer-reviewed journal Advanced Energy Materials [this seems to be an incorrectly cited journal; I believe it should be Nature Communications as indicated in the phys.org news item], the team, headed by Liangbing Hu of UMD’s Department of Materials Science and Engineering and the Energy Research Center lay out research showing that their transparent wood provides better thermal insulation and lets in nearly as much light as glass, while eliminating glare and providing uniform and consistent indoor lighting. The findings advance earlier published work on their development of transparent wood.

The transparent wood lets through just a little bit less light than glass, but a lot less heat, said Tian Li, the lead author of the new study. “It is very transparent, but still allows for a little bit of privacy because it is not completely see-through. We also learned that the channels in the wood transmit light with wavelengths around the range of the wavelengths of visible light, but that it blocks the wavelengths that carry mostly heat,” said Li.

The team’s findings were derived, in part, from tests on tiny model house with a transparent wood panel in the ceiling that the team built. The tests showed that the light was more evenly distributed around a space with a transparent wood roof than a glass roof.

The channels in the wood direct visible light straight through the material, but the cell structure that still remains bounces the light around just a little bit, a property called haze. This means the light does not shine directly into your eyes, making it more comfortable to look at. The team photographed the transparent wood’s cell structure in the University of Maryland’s Advanced Imaging and Microscopy (AIM) Lab.

Transparent wood still has all the cell structures that comprised the original piece of wood. The wood is cut against the grain, so that the channels that drew water and nutrients up from the roots lie along the shortest dimension of the window. The new transparent wood uses theses natural channels in wood to guide the sunlight through the wood.

As the sun passes over a house with glass windows, the angle at which light shines through the glass changes as the sun moves. With windows or panels made of transparent wood instead of glass, as the sun moves across the sky, the channels in the wood direct the sunlight in the same way every time.

“This means your cat would not have to get up out of its nice patch of sunlight every few minutes and move over,” Li said. “The sunlight would stay in the same place. Also, the room would be more equally lighted at all times.”

Working with transparent wood is similar to working with natural wood, the researchers said. However, their transparent wood is waterproof due to its polymer component. It also is much less breakable than glass because the cell structure inside resists shattering.

The research team has recently patented their process for making transparent wood. The process starts with bleaching from the wood all of the lignin, which is a component in the wood that makes it both brown and strong. The wood is then soaked in epoxy, which adds strength back in and also makes the wood clearer. The team has used tiny squares of linden wood about 2 cm x 2 cm, but the wood can be any size, the researchers said.

Here’s a link to and a citation for the July 31, 2020 paper,

Scalable aesthetic transparent wood for energy efficient buildings by Ruiyu Mi, Chaoji Chen, Tobias Keplinger, Yong Pei, Shuaiming He, Dapeng Liu, Jianguo Li, Jiaqi Dai, Emily Hitz, Bao Yang, Ingo Burgert & Liangbing Hu. Nature Communications volume 11, Article number: 3836 (2020) DOI: https://doi.org/10.1038/s41467-020-17513-w Published 31 July 2020

This paper is open access.

There were two previous posts about this work at the University of Maryland,

University of Maryland looks into transparent wood May 11, 2016 posting

Transparent wood more efficient than glass in windows? Sept, 8, 2016 posting

I also have this posting, which is also from 2016 but features work in Sweden,

Transparent wood instead of glass for window panes? April 1, 2016 posting

I seem to have stumbled across a number of transparent wood stories in 2016. Hmm I think I need to spend more time searching previous titles for my postings so I didn’t end up with too many that sound similar.

CRISPR (clustered regularly interspaced short palindromic repeats)-Cas9 in the forest

It seems lignin is a bit of a problem. Its presence in a tree makes processing the wood into various products more difficult. (Of course, some people appreciate trees for other reasons both practical [carbon sequestration?] and/or aesthetic.)

In any event, scientists have been working on ways to reduce the amount of lignin in poplar trees since at least 2014 (see my April 7, 2014 posting titled ‘Good lignin, bad lignin: Florida researchers use plant waste to create lignin nanotubes while researchers in British Columbia develop trees with less lignin’; scroll down about 40% of the way for the ‘less lignin’ story).

(I don’t believe the 2014 research was accomplished with the CRISPR (clustered regularly interspaced short palindromic repeats)-Cas9 technique as it had only been developed in 2012.)

The latest in the quest to reduce the amount of lignin of poplar trees comes from a Belgian/US team, from an Oct. 6, 2020 news item on ScienceDaily,

Researchers led by prof. Wout Boerjan (VIB-UGent [Ghent University] Center for Plant Systems Biology) have discovered a way to stably finetune the amount of lignin in poplar by applying CRISPR/Cas9 technology. Lignin is one of the main structural substances in plants and it makes processing wood into, for example, paper difficult. This study is an important breakthrough in the development of wood resources for the production of paper with a lower carbon footprint, biofuels, and other bio-based materials. Their work, in collaboration with VIVES University College (Roeselare, Belgium) and University of Wisconsin (USA) appears in Nature Communications.

Picture Tailoring lignin and growth by creating CCR2 allelic variants (From left to right: wild type, CCR2(-/-), CCR2(-/*) line 206, CCR2(-/*) line 12) Courtesy: VIB (Flanders Institute of Biotechnology)

An Oct. 6, 2020 VIB (Vlaams Instituut voor Biotechnologie; Flanders Institute of Biotechnology) press release (also on EurekAlert), which originated the news item, explains the reason for this research and how CRISPR (clustered regularly interspaced short palindromic repeats) technology could help realize it,

Towards a bio-based economy

Today’s fossil-based economy results in a net increase of CO2 in the Earth’s atmosphere and is a major cause of global climate change. To counter this, a shift towards a circular and bio-based economy is essential. Woody biomass can play a crucial role in such a bio-based economy by serving as a renewable and carbon-neutral resource for the production of many chemicals. Unfortunately, the presence of lignin hinders the processing of wood into bio-based products.

Prof. Wout Boerjan (VIB-UGent): “A few years ago, we performed a field trial with poplars that were engineered to make wood containing less lignin. Most plants showed large improvements in processing efficiency for many possible applications. The downside, however, was that the reduction in lignin accomplished with the technology we used then – RNA interference – was unstable and the trees grew less tall.”

New tools

Undeterred, the researchers went looking for a solution. They employed the recent CRISPR/Cas9 technology in poplar to lower the lignin amount in a stable way, without causing a biomass yield penalty. In other words, the trees grew just as well and as tall as those without genetic changes.

Dr. Barbara De Meester (VIB-UGent): “Poplar is a diploid species, meaning every gene is present in two copies. Using CRISPR/Cas9, we introduced specific changes in both copies of a gene that is crucial for the biosynthesis of lignin. We inactivated one copy of the gene, and only partially inactivated the other. The resulting poplar line had a stable 10% reduction in lignin amount while it grew normally in the greenhouse. Wood from the engineered trees had an up to 41% increase in processing efficiency”.

Dr. Ruben Vanholme (VIB-UGent): “The mutations that we have introduced through CRISPR/Cas9 are similar to those that spontaneously arise in nature. The advantage of the CRISPR/Cas9 method is that the beneficial mutations can be directly introduced into the DNA of highly productive tree varieties in only a fraction of the time it would take by a classical breeding strategy.”

The applications of this method are not only restricted to lignin but might also be useful to engineer other traits in crops, providing a versatile new breeding tool to improve agricultural productivity.

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

Tailoring poplar lignin without yield penalty by combining a null and haploinsufficient CINNAMOYL-CoA REDUCTASE2 allele by Barbara De Meester, Barbara Madariaga Calderón, Lisanne de Vries, Jacob Pollier, Geert Goeminne, Jan Van Doorsselaere, Mingjie Chen, John Ralph, Ruben Vanholme & Wout Boerjan. Nature Communications volume 11, Article number: 5020 (2020) DOI: https://doi.org/10.1038/s41467-020-18822-w Published 06 October 2020

This paper is open access.

Improving batteries with cellulosic nanomaterials

This is a cellulose nanocrystal (CNC) story and in this story it’s derived from trees as opposed to banana skins or carrots or … A February 19, 2020 news item on Nanowerk announces CNC research from Northeastern University (Massachusetts, US),

Nature isn’t always generous with its secrets. That’s why some researchers look into unusual places for solutions to our toughest challenges, from powerful antibiotics hiding in the guts of tiny worms, to swift robots inspired by bats.

Now, Northeastern researchers have taken to the trees to look for ways to make new sustainable materials from abundant natural resources—specifically, within the chemical structure of microfibers that make up wood.

A team led by Hongli (Julie) Zhu, an assistant professor of mechanical and industrial engineering at Northeastern, is using unique nanomaterials derived from cellulose to improve the large and expensive kind of batteries needed to store renewable energy harnessed from sources such as sunlight and the wind.

A February 18, 2020 Northeastern University news release by Roberto Molar Candanosa, which originated the news item, provides more detail (Note: Links have been removed),

Cellulose, the most abundant natural polymer on Earth, is also the most important structural component of plants. It contains important molecular structures to improve batteries, reduce plastic pollution, and power the sort of electrical grids that could support entire communities with renewable energy, Zhu says.  

“We try to use polymers from wood, from bark, from seeds, from flowers, bacteria, green tea—from these kinds of plants to replace plastic,”  Zhu says.

One of the main challenges in storing energy from the sun, wind, and other types of renewables is that variation in factors such as the weather lead to inconsistent sources of power. 

That’s where batteries with large capacity come in. But storing the large amounts of energy that sunlight and the wind are able to provide requires a special kind of device.

The most advanced batteries to do that are called flow batteries, and are made with vanadium ions dissolved in acid in two separate tanks—one with a substance of negatively charged ions, and one with positive ones. The two solutions are continuously pumped from the tank into a cell, which functions like an engine for the battery. 

These substances are always separated by a special membrane that ensures that they exchange positive hydrogen ions without flowing into each other. That selective exchange of ions is the basis for the ability of the battery to charge and discharge energy. 

Flow batteries are ideal devices in which to store solar and wind energy because they can be tweaked to increase the amount of energy stored without compromising the amount of energy that can be generated. The bigger the tanks, the more energy the battery can store from non-polluting and practically inexhaustible resources.

But manufacturing them requires several moving pieces of hardware. As the membrane separating the two flowing substances decays, it can cause the vanadium ions from the solution to mix. That crossover reduces the stability of a battery, along with its capacity to store energy.

Zhu says the limited efficiency of that membrane, combined with  its high cost, are the main factors keeping flow batteries from being widely used in large-scale grids.

In a recent paper, Zhu reported that a new membrane made with cellulose nanocrystals demonstrates superior efficiency compared to other membranes used commonly in the market. The team tested different membranes made from cellulose nanocrystals to make flow batteries cheaper.

“The cost of our membrane per square meter is 147.68 US dollars, ” Zhu says, adding that her calculations do not include costs associated with marketing. “The price quote for the commercialized Nafion membrane is $1,321 per square meter.”

Their tests also showed that the membranes, made with support from the Rogers Corporation and its Innovation Center at Northeastern’s Kostas Research Institute, can offer substantially longer battery lifetimes than other membranes. 

Zhu’s naturally derived membrane is especially efficient because its cellular structure contains thousands of hydroxyl groups, which involve bonds of hydrogen and oxygen that make it easy for water to be transported in plants and trees. 

In flow batteries, that molecular makeup speeds the transport of protons as they flow through the membrane.

The membrane also consists of another polymer known as poly(vinylidene fluoride-hexafluoropropylene), which prevents the negatively and positively charged acids from mixing with each other. 

“For these materials, one of the challenges is that it is difficult to find a polymer that is proton conductive and that is also a material that is very stable in the flowing acid,” Zhu says. 

Because these materials are practically everywhere, membranes made with it can be easily put together at large scales needed for complex power grids. 

Unlike other expensive artificial materials that need to be concocted in a lab, cellulose can be extracted from natural sources including algae, solid waste, and bacteria. 

“A lot of material in nature is a composite, and if we disintegrate its components, we can use it to extract cellulose,” Zhu says. “Like waste from our yard, and a lot of solid waste that we don’t always know what to do with.” 

Here’s a link to and a citation for the paper mentioned in the news release,

Stable and Highly Ion-Selective Membrane Made from Cellulose Nanocrystals for Aqueous Redox Flow Batteries by Alolika Mukhopadhyay, Zheng Cheng, Avi Natan, Yi Ma, Yang Yang, Daxian Cao, Wei Wan, Hongli Zhu. Nano Lett. 2019, 19, 12, 8979-8989 DOI: https://doi.org/10.1021/acs.nanolett.9b03964Publication Date:November 8, 2019 Copyright © 2019 American Chemical Society

This paper is behind a paywall.

Nanocellulose sensors: 3D printed and biocompatible

I do like to keep up with nanocellulose doings, especially when there’s some Canadian involvement, and an October 8, 2019 news item on Nanowerk alerted me to a newish application for the product,

Physiological parameters in our blood can be determined without painful punctures. Empa researchers are currently working with a Canadian team to develop flexible, biocompatible nanocellulose sensors that can be attached to the skin. The 3D-printed analytic chips made of renewable raw materials will even be biodegradable in future.

The idea of measuring parameters that are relevant for our health via the skin has already taken hold in medical diagnostics. Diabetics, for example, can painlessly determine their blood sugar level with a sensor instead of having to prick their fingers.

An October 8, 2019 Empa (Swiss Federal Laboratories for Materials Science and Technology) press release, which originated the news item, provides more detail,

A transparent foil made of wood

Nanocellulose is an inexpensive, renewable raw material, which can be obtained in form of crystals and fibers, for example from wood. However, the original appearance of a tree no longer has anything to do with the gelatinous substance, which can consist of cellulose nanocrystals and cellulose nanofibers. Other sources of the material are bacteria, algae or residues from agricultural production. Thus, nanocellulose is not only relatively easy and sustainable to obtain. Its mechanical properties also make the “super pudding” an interesting product. For instance, new composite materials based on nanocellulose can be developed that could be used as surface coatings, transparent packaging films or even to produce everyday objects like beverage bottles.

Researchers at Empa’s Cellulose & Wood Materials lab and Woo Soo Kim from the Simon Fraser University [SFU] in Burnaby, Canada, are also focusing on another feature of nanocellulose: biocompatibility. Since the material is obtained from natural resources, it is particularly suitable for biomedical research.

With the aim of producing biocompatible sensors that can measure important metabolic values, the researchers used nanocellulose as an “ink” in 3D printing processes. To make the sensors electrically conductive, the ink was mixed with silver nanowires. The researchers determined the exact ratio of nanocellulose and silver threads so that a three-dimensional network could form.

Just like spaghetti – only a wee bit smaller

It turned out that cellulose nanofibers are better suited than cellulose nanocrystals to produce a cross-linked matrix with the tiny silver wires. “Cellulose nanofibers are flexible similar to cooked spaghetti, but with a diameter of only about 20 nanometers and a length of just a few micrometers,” explains Empa researcher Gilberto Siqueira.

The team finally succeeded in developing sensors that measure medically relevant metabolic parameters such as the concentration of calcium, potassium and ammonium ions. The electrochemical skin sensor sends its results wirelessly to a computer for further data processing. The tiny biochemistry lab on the skin is only half a millimeter thin.

While the tiny biochemistry lab on the skin – which is only half a millimeter thin – is capable of determining ion concentrations specifically and reliably, the researchers are already working on an updated version. “In the future, we want to replace the silver [nano] particles with another conductive material, for example on the basis of carbon compounds,” Siqueira explains. This would make the medical nanocellulose sensor not only biocompatible, but also completely biodegradable.

I like the images from Empa better than the ones from SFU,

Using a 3D printer, the nanocellulose “ink” is applied to a carrier plate. Silver particles provide the electrical conductivity of the material. Image: Empa
Empa researcher Gilberto Siqueira demonstrates the newly printed nanocellulose circuit. After a subsequent drying, the material can be further processed. Image: Empa

SFU produced a news release about this work back in February 2019. Again, I prefer what the Swiss have done because they’re explaining/communicating the science, as well as , communicating benefits. From a February 13, 2019 SFU news release (Note: Links have been removed),

Simon Fraser University and Swiss researchers are developing an eco-friendly, 3D printable solution for producing wireless Internet-of-Things (IoT) sensors that can be used and disposed of without contaminating the environment. Their research has been published as the cover story in the February issue of the journal Advanced Electronic Materials.

SFU professor Woo Soo Kim is leading the research team’s discovery, which uses a wood-derived cellulose material to replace the plastics and polymeric materials currently used in electronics.

Additionally, 3D printing can give flexibility to add or embed functions onto 3D shapes or textiles, creating greater functionality.

“Our eco-friendly, 3D-printed cellulose sensors can wirelessly transmit data during their life, and then can be disposed without concern of environmental contamination,” says Kim, a professor in the School of Mechatronic Systems Engineering. The SFU research is being carried out at PowerTech Labs in Surrey, which houses several state-of-the-art 3D printers used to advance the research.

“This development will help to advance green electronics. For example, the waste from printed circuit boards is a hazardous source of contamination to the environment. If we are able to change the plastics in PCB to cellulose composite materials, recycling of metal components on the board could be collected in a much easier way.”

Kim’s research program spans two international collaborative projects, including the latest focusing on the eco-friendly cellulose material-based chemical sensors with collaborators from the Swiss Federal Laboratories for Materials Science.

He is also collaborating with a team of South Korean researchers from the Daegu Gyeongbuk Institute of Science and Technology’s (DGIST)’s department of Robotics Engineering, and PROTEM Co Inc, a technology-based company, for the development of printable conductive ink materials.

In this second project, researchers have developed a new breakthrough in the embossing process technology, one that can freely imprint fine circuit patterns on flexible polymer substrate, a necessary component of electronic products.

Embossing technology is applied for the mass imprinting of precise patterns at a low unit cost. However, Kim says it can only imprint circuit patterns that are imprinted beforehand on the pattern stamp, and the entire, costly stamp must be changed to put in different patterns.

The team succeeded in developing a precise location control system that can imprint patterns directly resulting in a new process technology. The result will have widespread implications for use in semiconductor processes, wearable devices and the display industry.

This paper was made available online back in December 2018 and then published in print in February 2019. As to why there’d be such large gaps between the paper’s publication dates and the two institution’s news/press releases, it’s a mystery to me. In any event, here’s a link to and a citation for the paper,

3D Printed Disposable Wireless Ion Sensors with Biocompatible Cellulose Composites by Taeil Kim, Chao Bao, Michael Hausmann, Gilberto Siqueira, Tanja Zimmermann, Woo Soo Kim. Advanced Electronic Materials DOI: https://doi.org/10.1002/aelm.201970007 First published online December 19, 2018. First published in print: 08 February 2019 (Adv. Electron. Mater. 2/2109) Volume 5, Issue 2 February 2019 1970007

This paper is behind a paywall.

A fire-retardant coating made of renewable nanocellulose materials

Firefighters everywhere are likely to appreciate the efforts of researchers at Texas A&M University (US) to a develop a non-toxic fire retardant coating. From a February 12, 2019 news item on Nanowerk (Note: A link has been removed),

Texas A&M University researchers are developing a new kind of flame-retardant coating using renewable, nontoxic materials readily found in nature, which could provide even more effective fire protection for several widely used materials.

Dr. Jaime Grunlan, the Linda & Ralph Schmidt ’68 Professor in the J. Mike Walker ’66 Department of Mechanical Engineering at Texas A&M, led the recently published research that is featured on the cover of a recent issue of the journal Advanced Materials Interfaces (“Super Gas Barrier and Fire Resistance of Nanoplatelet/Nanofibril Multilayer Thin Films”).

Successful development and implementation of the coating could provide better fire protection to materials including upholstered furniture, textiles and insulation.

“These coatings offer the opportunity to reduce the flammability of the polyurethane foam used in a variety of furniture throughout most people’s homes,” Grunlan noted.

A February 8, 2019 Texas A&M University news release (also on EurekAlert) by Steve Kuhlmann, which originated the news item, describes the work being done in collaboration with a Swedish team in more detail,

The project is a result of an ongoing collaboration between Grunlan and a group of researchers at KTH Royal Institute of Technology in Stockholm, Sweden, led by Lars Wagberg. The group, which specializes in utilizing nanocellulose, provided Grunlan with the ingredients he needed to complement his water-based coating procedure.

In nature, both the cellulose – a component of wood and various sea creatures – and clay – a component in soil and rock formations – act as mechanical reinforcements for the structures in which they are found.

“The uniqueness in this current study lies in the use of two naturally occurring nanomaterials, clay nanoplatelets and cellulose nanofibrils,” Grunlan said. “To the best of our knowledge, these ingredients have never been used to make a heat shielding or flame-retardant coating as a multilayer thin film deposited from water.”

Among the benefits gained from using this method include the coating’s ability to create an excellent oxygen barrier to plastic films – commonly used for food packaging – and better fire protection at a lower cost than other, more toxic ingredients traditionally used flame-retardant treatments.

To test the coatings, Grunlan and his colleagues applied the flexible polyurethane foam – often used in furniture cushions – and exposed it to fire using a butane torch to determine the level of protection the compounds provided.

While uncoated polyurethane foam immediately melts when exposed to flame, the foam treated with the researchers’ coating prevented the fire from damaging any further than surface level, leaving the foam underneath undamaged.

“The nanobrick wall structure of the coating reduces the temperature experienced by the underlying foam, which delays combustion,” Grunlan said. “This coating also serves to promote insulating char formation and reduces the release of fumes that feed a fire.”

With the research completed, Grunlan said the next step for the overall flame-retardant project is to transition the methods into industry for implementation and further development. 

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

Super Gas Barrier and Fire Resistance of Nanoplatelet/Nanofibril Multilayer Thin Films by Shuang Qin, Maryam Ghanad Pour, Simone Lazar, Oruç Köklükaya, Joseph Gerringer, Yixuan Song, Lars Wågberg, Jaime C. Grunlan. Advanced Materials Interfaces Volume 6, Issue 2 January 23, 2019 1801424 DOI: https://doi.org/10.1002/admi.201801424 First published online: 16 November 2018

This paper is behind a paywall.

Nanocellulosic 3D-printed ears

It’s been a while since I’ve had a story abut cellulose nanocrystals (CNC) and this one comes from Switzerland’s Empa (Swiss Federal Laboratories for Materials Science and Technology) in a January 15, 2019 news item on Nanowerk (Note: A link has been removed),

Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing (ACS Nano, “Dynamics of Cellulose Nanocrystal Alignment during 3D Printing”).

It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains: “In viscous state cellulose nanocrystals can easily be shaped together with nother biopolymers into complex 3-dimensional structures using a 3D printer, such as the Bioplotter.”

Once cross-linked, the structures remain stable despite their soft mechanical properties. Hausmann is currently investigating the characteristics of the nanocellulose composite hydrogels in order to further optimize their stability as well as the printing process. The researcher already used X-ray analysis to determine how cellulose is distributed and organized within the printed structures.

At this point in time the printed ear is entirely and solely made of cellulose nanocrystals and a biopolymer. However, the objective is to incorporate both human cells and therapeutics into the base structure in order to produce biomedical implants.

Here’s one of the researchers (Michael Hausmann) showing off their ‘ear’,

A 3D-printed ear: Empa researcher Michael Hausmann uses nanocellulose as the basis for novel implants (Image: Empa)

Doesn’t look like much does, eh? It’s scaffolding or, you could say, a kind of skeleton and a January 15, 2019 Empa press release, which originated the news item, describes it and explains how it will house new cells,

A new project is currently underway, looking into how chondrocytes (cartilage cells) can be integrated into the scaffold to yield artificial cartilage tissue. As soon as the colonization of the hydrogel with cells is established, nanocellulose based composites in the shape of an ear could serve as an implant for children with an inherited auricular malformation as for instance, in microtia, where the external ears are only incompletely developed. A reconstruction of the auricle can esthetically and medically correct the malformation; otherwise the hearing ability can be severely impaired. In the further course of the project, cellulose nanocrystals containing hydrogels will also be used for the replacement of articular cartilage (e.g. knee) in cases of joint wear due to, for example, chronic arthritis.

Once the artificial tissue has been implanted in the body, the biodegradable polymer material is expected to degrade over time. The cellulose itself is not degradable in the body, but biocompatible. However, it is not only its biocompatibility that makes nanocellulose the perfect material for implant scaffolds. “It is also the mechanical performance of cellulose nanocrystals that make them such promising candidates because the tiny but highly stable fibers can extremely well reinforce the produced implant,” said Hausmann.

Moreover, nanocellulose allows the incorporation of various functions by chemical modifications into the viscous hydrogel. Thus, the structure, the mechanical properties and the interactions of the nanocellulose with its environment can be specifically tailored to the desired end product. “For instance, we can incorporate active substances that promote the growth of chondrocytes or that sooth joint inflammation into the hydrogel,” says the Empa researcher.

And last but not least, as raw material cellulose is the most abundant natural polymer on earth. Therefore, the use of cellulose nanocrystals not only benefits from the mere elegance of the novel process but also from the availability of the raw material.

The white nanocellulose ear lies glossy on the glass carrier. Just out of the Bioplotter, it is already robust and dimensionally stable. Hausmann can give the go-ahead for the next steps. 

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

Dynamics of Cellulose Nanocrystal Alignment during 3D Printing by Michael K. Hausmann, Patrick A. Rühs, Gilberto Siqueira, Jörg Läuger, Rafael Libanori, Tanja Zimmermann, and André R. Studart. ACS Nano, 2018, 12 (7), pp 6926–6937 DOI: 10.1021/acsnano.8b02366 Publication Date (Web): July 5, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

Two new Canada Excellence Research Chairs (CERC) at the University of British Columbia (Canada) bring bioproducts and precision medicine skills

This is very fresh news. One of these chairs has not yet been listed (at the time of this writing) as a member of the institute that he will be leading. Here’s the big picture news from an
April 17, 2019 University of British Columbia (UBC) news release, Note: Links have been removed,

Two internationally recognized researchers join the University of British Columbia as Canada Excellence Research Chairs, bringing international talent in the fields of forest bioproducts and precision cancer drug design.

Orlando Rojas has accepted the Canada Excellence Research Chair in Forest Bioproducts, while Sriram Subramaniam will hold the Gobind Khorana Canada Excellence Research Chair in Precision Cancer Drug Design—named after late Nobel Prize-winning UBC biochemistry professor Har Gobind Khorana.

“We are delighted to welcome Dr. Rojas and Dr. Subramaniam to UBC,” said UBC President and Vice-Chancellor, Professor Santa J. Ono. “Thanks to the CERC program and the generous support of our partners, including VGH & UBC Hospital Foundation, we have an opportunity to continue to build on UBC’s reputation as a global leader in these vitally important research fields.”

The Canada Excellence Research Chairs (CERC) program was established by the federal government in 2008 to attract top research talent from abroad to Canada. UBC will receive up to $10 million over seven years to support each chair and their research teams. In addition, a philanthropic gift of $18 million made to VGH & UBC Hospital Foundation will support cancer drug design that will be carried out by Subramaniam in close partnership with UBC and the Vancouver Prostate Centre at VGH.

“VGH & UBC Hospital Foundation is honoured to announce an $18 million gift from Aqueduct Foundation on behalf of an anonymous donor that will increase capacity for discovering and testing new life-saving cancer treatments right here in B.C. This funding will specifically support the design of precise, targeted and cost-effective drugs for cancer in work led by Dr. Sriram Subramaniam in close partnership with UBC and the Vancouver Prostate Centre at VGH and other research centres,” says Barbara Grantham, president and CEO of VGH & UBC Hospital Foundation.

Bioproducts

The April 17, 2019 UBC news release, goes on to describe the two new chairs,

Breaking new ground in forest bioproducts

Orlando Rojas comes to UBC from Aalto University [Finland], where he directs with VTT, the Technical Research Centre of Finland, a scientific cluster to advance the Finnish materials bio-economy. A recipient of the Anselme Payen Award—one of the highest international recognitions in the area of cellulose and renewable materials—and an elected member of the American Chemical Society and the Finnish Academy of Science and Letters, Rojas is recognized as a worldwide leader in the area of nanocelluloses.

“I’m thrilled to join an already stellar team of researchers at UBC’s BioProducts Institute,” said Rojas. “My research is aimed at uncovering solutions that can be found in nature to fulfill our material needs by using sustainably, readily available bio-resources. I hope to break new grounds to create positive societal impacts and to better our quality of life.”

As the CERC in Forest Bioproducts, Rojas will establish a world-class research program in genomics, synthetic biology, materials science and engineering. Together with his team and by applying cutting-edge nano- and biotechnologies, he will discover new strategies to isolate and transform biomass components—non-fossil organic materials derived from plants (including wood)—as well as side-streams and residuals from forestry and agriculture, oils and biomolecules. The work will lead to the generation of new bio-based precursors and advanced materials critical to the future bioeconomy. Rojas will be the scientific director of the UBC BioProducts Institute, synergizing a distinguished group of professors and researchers across campus who will conduct multi- and cross-disciplinary research that will position UBC at the forefront in the area.

As climate change continues to be the greatest threat to our world, the need to transition toward a more sustainable bio-based circular economy is critical. Rojas’ research is vital in understanding the role of forest and other plant-based resources in facilitating the transition to renewable materials and bioproducts.

As I noted earlier, Rojas has yet to be added to the UBC BioProducts Institute roster but I did find a listing of his published papers on Google Scholar and noted a number of them are focused on nanocellulose with at least one study on cellulose nanocrystals (CNC),

  • Cellulose nanocrystals: chemistry, self-assembly, and applications [by] Y Habibi, LA Lucia, OJ Rojas Chemical reviews 110 (6), 3479-3500

The University of British Columbia was the site for much of the early work in Canada and internationally on cellulose nanocrystals. After the provincial government lost interest in supporting it, the researchers at FPInnovations (I think it was a university spin-off organization) moved their main headquarters (leaving a smaller group in British Columbia) to the province of Québec where they receive significant support . In turn, FPInnovations spun-off a company, CelluForce which produces CNC from forest products.This news about Roja’s appointment would seem to make for an interesting development in Canada’s nanocellulose story.

Precision medicine with cryo-electron microscopy

Now for the second CERC appointment, from the April 17, 2019 UBC news release,

Putting Canada at the forefront of precision medicine

Sriram Subramaniam is recognized as a global leader in the emerging field of cryo-electron microscopy, or cryo-EM, a technology that has sparked a revolution in imaging of protein complexes. Subramaniam and his team demonstrated that proteins and protein-bound drugs could be visualized at atomic resolution with cryo-EM, paving the way for this technology to be used in accelerating drug discovery.

Subramaniam comes to UBC’s faculty of medicine from the US National Cancer Institute (NCI) at the National Institutes of Health (NIH) where he led a research team that made seminal advances in molecular and cellular imaging using electron microscopy, including work on advancing vaccine design for viruses such as HIV. Subramaniam is also founding director of the National Cryo-EM Program at NCI, NIH.

As the Gobind Khorana Canada Excellence Research Chair in Precision Cancer Drug Design, Subramaniam will establish and direct a laboratory located at UBC, aimed at bringing about transformative discoveries in cancer, neuroscience and infectious disease. Subramaniam is appointed both in the department of urologic sciences and in biochemistry and molecular biology at UBC, and is linked to the precision cancer drug design program at the Vancouver Prostate Centre at VGH.

His research is supported by a philanthropic gift of $18 million made to VGH & UBC Hospital Foundation. He will work in close partnership with the Vancouver Prostate Centre at VGH.

“We would not be able to undertake this path aimed at leveraging advances in imaging technology to improve patient outcomes if it weren’t for the generous support of the donor, the Canadian government, and VGH & UBC Hospital Foundation,” said Subramaniam. “I am proud to be part of a team of outstanding researchers here in Vancouver, and working together to harness the true potential of cryo-EM to accelerate drug design. Our work has the potential to establish VGH, UBC and Canada at the forefront of the emerging era of precision medicine.”

I was not able to find much in the way of additional information about Subramaniam—other than this (from the High Resolution Electron Microscopy Lab Members webpage),

Sriram Subramaniam received his Ph.D. in Physical Chemistry from Stanford University and completed postdoctoral training in the Departments of Chemistry and Biology at M.I.T. [Massachusetts Institute of Technology] He is chief of the Biophysics Section in the Laboratory of Cell Biology at the Center for Cancer Research, National Cancer Institute. He holds a visiting faculty appointment at the Johns Hopkins University School of Medicine.

Welcome to both Orlando J. Rohas and Sriram Subramaniam!

Stronger than steel and spider silk: artificial, biodegradable, cellulose nanofibres

This is an artificial and biodegradable are two adjectives you don’t usually see united by the conjunction, and. However, it is worth noting that the artificial material is initially derived from a natural material, cellulose. Here’s more from a May 16, 2018 news item on ScienceDaily,

At DESY’s [Deutsches Elektronen-Synchrotron] X-ray light source PETRA III, a team led by Swedish researchers has produced the strongest bio-material that has ever been made. The artifical, but bio-degradable cellulose fibres are stronger than steel and even than dragline spider silk, which is usually considered the strongest bio-based material. The team headed by Daniel Söderberg from the KTH Royal Institute of Technology in Stockholm reports the work in the journal ACS Nano of the American Chemical Society.

A May 16, 2018 DESY press release (also on EurekAlert), which originated the news item, provides more detail,

The ultrastrong material is made of cellulose nanofibres (CNF), the essential building blocks of wood and other plant life. Using a novel production method, the researchers have successfully transferred the unique mechanical properties of these nanofibres to a macroscopic, lightweight material that could be used as an eco-friendly alternative for plastic in airplanes, cars, furniture and other products. “Our new material even has potential for biomedicine since cellulose is not rejected by your body”, explains Söderberg.

The scientists started with commercially available cellulose nanofibres that are just 2 to 5 nanometres in diameter and up to 700 nanometres long. A nanometre (nm) is a millionth of a millimetre. The nanofibres were suspended in water and fed into a small channel, just one millimetre wide and milled in steel. Through two pairs of perpendicular inflows additional deionized water and water with a low pH-value entered the channel from the sides, squeezing the stream of nanofibres together and accelerating it.

This process, called hydrodynamic focussing, helped to align the nanofibres in the right direction as well as their self-organisation into a well-packed macroscopic thread. No glue or any other component is needed, the nanofibres assemble into a tight thread held together by supramolecular forces between the nanofibres, for example electrostatic and Van der Waals forces.

With the bright X-rays from PETRA III the scientists could follow and optimise the process. “The X-rays allow us to analyse the detailed structure of the thread as it forms as well as the material structure and hierarchical order in the super strong fibres,” explains co-author Stephan Roth from DESY, head of the Micro- and Nanofocus X-ray Scattering Beamline P03 where the threads were spun. “We made threads up to 15 micrometres thick and several metres in length.”

Measurements showed a tensile stiffness of 86 gigapascals (GPa) for the material and a tensile strength of 1.57 GPa. “The bio-based nanocellulose fibres fabricated here are 8 times stiffer and have strengths higher than natural dragline spider silk fibres,” says Söderberg. “If you are looking for a bio-based material, there is nothing quite like it. And it is also stronger than steel and any other metal or alloy as well as glass fibres and most other synthetic materials.” The artificial cellulose fibres can be woven into a fabric to create materials for various applications. The researchers estimate that the production costs of the new material can compete with those of strong synthetic fabrics. “The new material can in principle be used to create bio-degradable components,” adds Roth.

The study describes a new method that mimics nature’s ability to accumulate cellulose nanofibres into almost perfect macroscale arrangements, like in wood. It opens the way for developing nanofibre material that can be used for larger structures while retaining the nanofibres’ tensile strength and ability to withstand mechanical load. “We can now transform the super performance from the nanoscale to the macroscale,” Söderberg underlines. “This discovery is made possible by understanding and controlling the key fundamental parameters essential for perfect nanostructuring, such as particle size, interactions, alignment, diffusion, network formation and assembly.” The process can also be used to control nanoscale assembly of carbon tubes and other nano-sized fibres.

(There are some terminology and spelling issues, which are described at the end of this post.)

Let’s get back to a material that rivals spider silk and steel for strength (for some reason that reminded me of an old carnival game where you’d test your strength by swinging a mallet down on a ‘teeter-totter-like’ board and sending a metal piece up a post to make a bell ring). From a May 16, 2018 DESY press release (also on EurekAlert), which originated the news item,

The ultrastrong material is made of cellulose nanofibres (CNF), the essential building blocks of wood and other plant life. Using a novel production method, the researchers have successfully transferred the unique mechanical properties of these nanofibres to a macroscopic, lightweight material that could be used as an eco-friendly alternative for plastic in airplanes, cars, furniture and other products. “Our new material even has potential for biomedicine since cellulose is not rejected by your body”, explains Söderberg.

The scientists started with commercially available cellulose nanofibres that are just 2 to 5 nanometres in diameter and up to 700 nanometres long. A nanometre (nm) is a millionth of a millimetre. The nanofibres were suspended in water and fed into a small channel, just one millimetre wide and milled in steel. Through two pairs of perpendicular inflows additional deionized water and water with a low pH-value entered the channel from the sides, squeezing the stream of nanofibres together and accelerating it.

This process, called hydrodynamic focussing, helped to align the nanofibres in the right direction as well as their self-organisation into a well-packed macroscopic thread. No glue or any other component is needed, the nanofibres assemble into a tight thread held together by supramolecular forces between the nanofibres, for example electrostatic and Van der Waals forces.

With the bright X-rays from PETRA III the scientists could follow and optimise the process. “The X-rays allow us to analyse the detailed structure of the thread as it forms as well as the material structure and hierarchical order in the super strong fibres,” explains co-author Stephan Roth from DESY, head of the Micro- and Nanofocus X-ray Scattering Beamline P03 where the threads were spun. “We made threads up to 15 micrometres thick and several metres in length.”

Measurements showed a tensile stiffness of 86 gigapascals (GPa) for the material and a tensile strength of 1.57 GPa. “The bio-based nanocellulose fibres fabricated here are 8 times stiffer and have strengths higher than natural dragline spider silk fibres,” says Söderberg. “If you are looking for a bio-based material, there is nothing quite like it. And it is also stronger than steel and any other metal or alloy as well as glass fibres and most other synthetic materials.” The artificial cellulose fibres can be woven into a fabric to create materials for various applications. The researchers estimate that the production costs of the new material can compete with those of strong synthetic fabrics. “The new material can in principle be used to create bio-degradable components,” adds Roth.

The study describes a new method that mimics nature’s ability to accumulate cellulose nanofibres into almost perfect macroscale arrangements, like in wood. It opens the way for developing nanofibre material that can be used for larger structures while retaining the nanofibres’ tensile strength and ability to withstand mechanical load. “We can now transform the super performance from the nanoscale to the macroscale,” Söderberg underlines. “This discovery is made possible by understanding and controlling the key fundamental parameters essential for perfect nanostructuring, such as particle size, interactions, alignment, diffusion, network formation and assembly.” The process can also be used to control nanoscale assembly of carbon tubes and other nano-sized fibres.

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

Multiscale Control of Nanocellulose Assembly: Transferring Remarkable Nanoscale Fibril Mechanics to Macroscale Fibers by Nitesh Mittal, Farhan Ansari, Krishne Gowda V, Christophe Brouzet, Pan Chen, Per Tomas Larsson, Stephan V. Roth, Fredrik Lundell, Lars Wågberg, Nicholas A. Kotov, and L. Daniel Söderberg. ACS Nano, Article ASAP DOI: 10.1021/acsnano.8b01084 Publication Date (Web): May 9, 2018

Copyright © 2018 American Chemical Society

This paper is open access and accompanied by this image illustrating the work,

Courtesy: American Chemical Society and the researchers [Note: The bottom two images of cellulose nanofibres, which are constittuents of an artificial cellulose fibre, appear to be from a scanning tunneling microsscope. Credit: Nitesh Mittal, KTH Stockholm

This news has excited interest at General Electric (GE) (its Wikipedia entry), which has highlighted the work in a May 25, 2018 posting (The 5 Coolest Things On Earth This Week) by Tomas Kellner on the GE Reports blog.

Terminology and spelling

I’ll start with spelling since that’s the easier of the two. In some parts of the world it’s spelled ‘fibres’ and in other parts of the world it’s spelled ‘fibers’. When I write the text in my post, it tends to reflect the spelling used in the news/press releases. In other words, I swing in whichever direction the wind is blowing.

For diehards only

As i understand the terminology situation, nanocellulose and cellulose nanomaterials are interchangeable generic terms. Further, cellulose nanofibres (CNF) seems to be another generic term and it encompasses both cellulose nanocrystals (CNC) and cellulose nanofibrils (CNF). Yes, there appear to be two CNFs. Making matters more interesting is the fact that cellulose nanocrystals were originally christened nanocrystalline cellulose (NCC). For anyone who follows the science and technology scene, it becomes obvious that competing terminologies are the order of the day. Eventually the dust settles and naming conventions are resolved. More or less.

Ordinarily I would reference the Nanocellulose Wikipedia entry in my attempts to clarify the issues but it seems that the writers for the entry have not caught up to the current naming convention for cellulose nanocrystals, still referring to the material as nanocrystalline cellulose. This means, I can’t trust the rest of the entry, which has only one CNF (cellulose nanofibres).

I have paid more attention to the NCC/CNC situation and am not as familiar with the CNF situation. Using, NCC/CNC as an example of a terminology issue, I believe it was first developed in Canada and it was Canadian researchers who were pushing their NCC terminology while the international community pushed back with CNC.

In the end, NCC became a brand name, which was trademarked by CelluForce, a Canadian company in the CNC market. From the CelluForce Products page on Cellulose Nanocrystals,

CNC are not all made equal. The CNC produced by CelluForce is called CelluForce NCCTM and has specific properties and are especially easy to disperse. CelluForce NCCTM is the base material that CelluForce uses in all its products. This base material can be modified and tailored to suit the specific needs in various applications.

These, days CNC is almost universally used but NCC (not as a trademark) is a term still employed on occasion (and, oddly, the researchers are not necessarily Canadian).

Should anyone have better information about terminology issues, please feel free to comment.

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.