Tag Archives: Liangbing Hu

Windows and roofs ‘self-adapt’ to heating and cooling conditions

I have two items about thermochromic coatings. It’s a little confusing since the American Association for the Advancement of Science (AAAS), which publishes the journal featuring both papers has issued a news release that seemingly refers to both papers as a single piece of research.

Onto, the press/new releases from the research institutions to be followed by the AAAS news release.

Nanyang Technological University (NTU) does windows

A December 16, 2021 news item on Nanowerk announced work on energy-saving glass,

An international research team led by scientists from Nanyang Technological University, Singapore (NTU Singapore) has developed a material that, when coated on a glass window panel, can effectively self-adapt to heat or cool rooms across different climate zones in the world, helping to cut energy usage.

Developed by NTU researchers and reported in the journal Science (“Scalable thermochromic smart windows with passive radiative cooling regulation”), the first-of-its-kind glass automatically responds to changing temperatures by switching between heating and cooling.

The self-adaptive glass is developed using layers of vanadium dioxide nanoparticles composite, Poly(methyl methacrylate) (PMMA), and low-emissivity coating to form a unique structure which could modulate heating and cooling simultaneously.

A December 17, 2021 NTU press release (PDF), also on EurekAlert but published December 16, 2021, which originated the news item, delves further into the research (Note: A link has been removed),

The newly developed glass, which has no electrical components, works by exploiting the spectrums of light responsible for heating and cooling.

During summer, the glass suppresses solar heating (near infrared light), while boosting radiative cooling (long-wave infrared) – a natural phenomenon where heat emits through surfaces towards the cold universe – to cool the room. In the winter, it does the opposite to warm up the room.

In lab tests using an infrared camera to visualise results, the glass allowed a controlled amount of heat to emit in various conditions (room temperature – above 70°C), proving its ability to react dynamically to changing weather conditions.

New glass regulates both heating and cooling

Windows are one of the key components in a building’s design, but they are also the least energy-efficient and most complicated part. In the United States alone, window-associated energy consumption (heating and cooling) in buildings accounts for approximately four per cent of their total primary energy usage each year according to an estimation based on data available from the Department of Energy in US.[1]

While scientists elsewhere have developed sustainable innovations to ease this energy demand – such as using low emissivity coatings to prevent heat transfer and electrochromic glass that regulate solar transmission from entering the room by becoming tinted – none of the solutions have been able to modulate both heating and cooling at the same time, until now.

The principal investigator of the study, Dr Long Yi of the NTU School of Materials Science and Engineering (MSE) said, “Most energy-saving windows today tackle the part of solar heat gain caused by visible and near infrared sunlight. However, researchers often overlook the radiative cooling in the long wavelength infrared. While innovations focusing on radiative cooling have been used on walls and roofs, this function becomes undesirable during winter. Our team has demonstrated for the first time a glass that can respond favourably to both wavelengths, meaning that it can continuously self-tune to react to a changing temperature across all seasons.”

As a result of these features, the NTU research team believes their innovation offers a convenient way to conserve energy in buildings since it does not rely on any moving components, electrical mechanisms, or blocking views, to function.

To improve the performance of windows, the simultaneous modulation of both solar transmission and radiative cooling are crucial, said co-authors Professor Gang Tan from The University of Wyoming, USA, and Professor Ronggui Yang from the Huazhong University of Science and Technology, Wuhan, China, who led the building energy saving simulation.

“This innovation fills the missing gap between traditional smart windows and radiative cooling by paving a new research direction to minimise energy consumption,” said Prof Gang Tan.

The study is an example of groundbreaking research that supports the NTU 2025 strategic plan, which seeks to address humanity’s grand challenges on sustainability, and accelerate the translation of research discoveries into innovations that mitigate human impact on the environment.

Innovation useful for a wide range of climate types

As a proof of concept, the scientists tested the energy-saving performance of their invention using simulations of climate data covering all populated parts of the globe (seven climate zones).

The team found the glass they developed showed energy savings in both warm and cool seasons, with an overall energy saving performance of up to 9.5%, or ~330,000 kWh per year (estimated energy required to power 60 household in Singapore for a year) less than commercially available low emissivity glass in a simulated medium sized office building.

First author of the study Wang Shancheng, who is Research Fellow and former PhD student of Dr Long Yi, said, “The results prove the viability of applying our glass in all types of climates as it is able to help cut energy use regardless of hot and cold seasonal temperature fluctuations. This sets our invention apart from current energy-saving windows which tend to find limited use in regions with less seasonal variations.”

Moreover, the heating and cooling performance of their glass can be customised to suit the needs of the market and region for which it is intended.

“We can do so by simply adjusting the structure and composition of special nanocomposite coating layered onto the glass panel, allowing our innovation to be potentially used across a wide range of heat regulating applications, and not limited to windows,” Dr Long Yi said.

Providing an independent view, Professor Liangbing Hu, Herbert Rabin Distinguished Professor, Director of the Center for Materials Innovation at the University of Maryland, USA, said, “Long and co-workers made the original development of smart windows that can regulate the near-infrared sunlight and the long-wave infrared heat. The use of this smart window could be highly important for building energy-saving and decarbonization.”  

A Singapore patent has been filed for the innovation. As the next steps, the research team is aiming to achieve even higher energy-saving performance by working on the design of their nanocomposite coating.

The international research team also includes scientists from Nanjing Tech University, China. The study is supported by the Singapore-HUJ Alliance for Research and Enterprise (SHARE), under the Campus for Research Excellence and Technological Enterprise (CREATE) programme, Minster of Education Research Fund Tier 1, and the Sino-Singapore International Joint Research Institute.

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

Scalable thermochromic smart windows with passive radiative cooling regulation by Shancheng Wang, Tengyao Jiang, Yun Meng, Ronggui Yang, Gang Tan, and Yi Long. Science • 16 Dec 2021 • Vol 374, Issue 6574 • pp. 1501-1504 • DOI: 10.1126/science.abg0291

This paper is behind a paywall.

Lawrence Berkeley National Laboratory (Berkeley Lab; LBNL) does roofs

A December 16, 2021 Lawrence Berkeley National Laboratory news release (also on EurekAlert) announces an energy-saving coating for roofs (Note: Links have been removed),

Scientists have developed an all-season smart-roof coating that keeps homes warm during the winter and cool during the summer without consuming natural gas or electricity. Research findings reported in the journal Science point to a groundbreaking technology that outperforms commercial cool-roof systems in energy savings.

“Our all-season roof coating automatically switches from keeping you cool to warm, depending on outdoor air temperature. This is energy-free, emission-free air conditioning and heating, all in one device,” said Junqiao Wu, a faculty scientist in Berkeley Lab’s Materials Sciences Division and a UC Berkeley professor of materials science and engineering who led the study.

Today’s cool roof systems, such as reflective coatings, membranes, shingles, or tiles, have light-colored or darker “cool-colored” surfaces that cool homes by reflecting sunlight. These systems also emit some of the absorbed solar heat as thermal-infrared radiation; in this natural process known as radiative cooling, thermal-infrared light is radiated away from the surface.

The problem with many cool-roof systems currently on the market is that they continue to radiate heat in the winter, which drives up heating costs, Wu explained.

“Our new material – called a temperature-adaptive radiative coating or TARC – can enable energy savings by automatically turning off the radiative cooling in the winter, overcoming the problem of overcooling,” he said.

A roof for all seasons

Metals are typically good conductors of electricity and heat. In 2017, Wu and his research team discovered that electrons in vanadium dioxide behave like a metal to electricity but an insulator to heat – in other words, they conduct electricity well without conducting much heat. “This behavior contrasts with most other metals where electrons conduct heat and electricity proportionally,” Wu explained.

Vanadium dioxide below about 67 degrees Celsius (153 degrees Fahrenheit) is also transparent to (and hence not absorptive of) thermal-infrared light. But once vanadium dioxide reaches 67 degrees Celsius, it switches to a metal state, becoming absorptive of thermal-infrared light. This ability to switch from one phase to another – in this case, from an insulator to a metal – is characteristic of what’s known as a phase-change material.

To see how vanadium dioxide would perform in a roof system, Wu and his team engineered a 2-centimeter-by-2-centimeter TARC thin-film device.

TARC “looks like Scotch tape, and can be affixed to a solid surface like a rooftop,” Wu said.

In a key experiment, co-lead author Kechao Tang set up a rooftop experiment at Wu’s East Bay home last summer to demonstrate the technology’s viability in a real-world environment.

A wireless measurement device set up on Wu’s balcony continuously recorded responses to changes in direct sunlight and outdoor temperature from a TARC sample, a commercial dark roof sample, and a commercial white roof sample over multiple days.

How TARC outperforms in energy savings

The researchers then used data from the experiment to simulate how TARC would perform year-round in cities representing 15 different climate zones across the continental U.S.

Wu enlisted Ronnen Levinson, a co-author on the study who is a staff scientist and leader of the Heat Island Group in Berkeley Lab’s Energy Technologies Area, to help them refine their model of roof surface temperature. Levinson developed a method to estimate TARC energy savings from a set of more than 100,000 building energy simulations that the Heat Island Group previously performed to evaluate the benefits of cool roofs and cool walls across the United States.

Finnegan Reichertz, a 12th grade student at the East Bay Innovation Academy in Oakland who worked remotely as a summer intern for Wu last year, helped to simulate how TARC and the other roof materials would perform at specific times and on specific days throughout the year for each of the 15 cities or climate zones the researchers studied for the paper.

The researchers found that TARC outperforms existing roof coatings for energy saving in 12 of the 15 climate zones, particularly in regions with wide temperature variations between day and night, such as the San Francisco Bay Area, or between winter and summer, such as New York City.

“With TARC installed, the average household in the U.S. could save up to 10% electricity,” said Tang, who was a postdoctoral researcher in the Wu lab at the time of the study. He is now an assistant professor at Peking University in Beijing, China.

Standard cool roofs have high solar reflectance and high thermal emittance (the ability to release heat by emitting thermal-infrared radiation) even in cool weather.

According to the researchers’ measurements, TARC reflects around 75% of sunlight year-round, but its thermal emittance is high (about 90%) when the ambient temperature is warm (above 25 degrees Celsius or 77 degrees Fahrenheit), promoting heat loss to the sky. In cooler weather, TARC’s thermal emittance automatically switches to low, helping to retain heat from solar absorption and indoor heating, Levinson said.

Findings from infrared spectroscopy experiments using advanced tools at Berkeley Lab’s Molecular Foundry validated the simulations.

“Simple physics predicted TARC would work, but we were surprised it would work so well,” said Wu. “We originally thought the switch from warming to cooling wouldn’t be so dramatic. Our simulations, outdoor experiments, and lab experiments proved otherwise – it’s really exciting.”

The researchers plan to develop TARC prototypes on a larger scale to further test its performance as a practical roof coating. Wu said that TARC may also have potential as a thermally protective coating to prolong battery life in smartphones and laptops, and shield satellites and cars from extremely high or low temperatures. It could also be used to make temperature-regulating fabric for tents, greenhouse coverings, and even hats and jackets.

Co-lead authors on the study were Kaichen Dong and Jiachen Li.

The Molecular Foundry is a nanoscience user facility at Berkeley Lab.

This work was primarily supported by the DOE Office of Science and a Bakar Fellowship.

The technology is available for licensing and collaboration. If interested, please contact Berkeley Lab’s Intellectual Property Office, ipo@lbl.gov.

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

Temperature-adaptive radiative coating for all-season household thermal regulation by Kechao Tang, Kaichen Dong, Jiachen Li, Madeleine P. Gordon, Finnegan G. Reichertz, Hyungjin Kim, Yoonsoo Rho, Qingjun Wang, Chang-Yu Lin, Costas P. Grigoropoulos, Ali Javey, Jeffrey J. Urban, Jie Yao, Ronnen Levinson, Junqiao Wu. Science • 16 Dec 2021 • Vol 374, Issue 6574 • pp. 1504-1509 • DOI: 10.1126/science.abf7136

This paper is behind a paywall.

An interesting news release from the AAAS

While it’s a little confusing as it cites only the ‘window’ research from NTU, the body of this news release offers some additional information about the usefulness of thermochromic materials and seemingly refers to both papers, from a December 16, 2021 AAAS news release,

Temperature-adaptive passive radiative cooling for roofs and windows

When it’s cold out, window glass and roof coatings that use passive radiative cooling to keep buildings cool can be designed to passively turn off radiative cooling to avoid heat loss, two new studies show.  Their proof-of-concept analyses demonstrate that passive radiative cooling can be expanded to warm and cold climate applications and regions, potentially providing all-season energy savings worldwide. Buildings consume roughly 40% of global energy, a large proportion of which is used to keep them cool in warmer climates. However, most temperature regulation systems commonly employed are not very energy efficient and require external power or resources. In contrast, passive radiative cooling technologies, which use outer space as a near-limitless natural heat sink, have been extensively examined as a means of energy-efficient cooling for buildings. This technology uses materials designed to selectively emit narrow-band radiation through the infrared atmospheric window to disperse heat energy into the coldness of space. However, while this approach has proven effective in cooling buildings to below ambient temperatures, it is only helpful during the warmer months or in regions that are perpetually hot. Furthermore, the inability to “turn off” passive cooling in cooler climes or in regions with large seasonal temperature variations means that continuous cooling during colder periods would exacerbate the energy costs of heating. In two different studies, by Shancheng Wang and colleagues and Kechao Tang and colleagues, researchers approach passive radiative cooling from an all-season perspective and present a new, scalable temperature-adaptive radiative technology that passively turns off radiative cooling at lower temperatures. Wang et al. and Tang et al. achieve this using a tungsten-doped vanadium dioxide and show how it can be applied to create both window glass and a flexible roof coating, respectively. Model simulations of the self-adapting materials suggest they could provide year-round energy savings across most climate zones, especially those with substantial seasonal temperature variations. 

I wish them all good luck with getting these materials to market.

Sunlight makes transparent wood even lighter and stronger

Researchers at the University of Maryland (US) have found a way to make their wood transparent by using sunlight. From a February 2, 2021 news article by Bob Yirka on phys.org (Note: Links have been removed),

A team of researchers at the University of Maryland, has found a new way to make wood transparent. In their paper published in the journal Science Advances, the group describes their process and why they believe it is better than the old process.

The conventional method for making wood transparent involves using chemicals to remove the lignin—a process that takes a long time, produces a lot of liquid waste and results in weaker wood. In this new effort, the researchers have found a way to make wood transparent without having to remove the lignin.

The process involved changing the lignin rather than removing it. The researchers removed lignin molecules that are involved in producing wood color. First, they applied hydrogen peroxide to the wood surface and then exposed the treated wood to UV light (or natural sunlight). The wood was then soaked in ethanol to further clean it. Next, they filled in the pores with clear epoxy to make the wood smooth.

Caption: Solar-assisted large-scale fabrication of transparent wood. (A) Schematic showing the potential large-scale fabrication of transparent wood based on the rotary wood cutting method and the solar-assisted chemical brushing process. (B) The outdoor fabrication of lignin-modified wood with a length of 1 m [9 August 2019 (the summer months) at 13:00 p.m. (solar noon), the Global Solar UV Index (UVI): 7 to 8]. (C) Digital photo of a piece of large transparent wood (400 mm by 110 mm by 1 mm). (D) The energy consumption, chemical cost, and waste emission for the solar-assisted chemical brushing process and NaClO2 solution–based delignification process. (E) A radar plot showing a comparison of the fabrication process for transparent wood. Photo credit: Qinqin Xia, University of Maryland, College Park. [downloaded from https://advances.sciencemag.org/content/7/5/eabd7342]

Bob McDonald in a February 5, 2021 posting on his Canadian Broadcasting Corporation (CBC) Quirks & Quarks blog provides a more detailed description of the new ‘solar-based transparency process’,

Early attempts to make transparent wood involved removing the lignin, but this involved hazardous chemicals, high temperatures and a lot of time, making the product expensive and somewhat brittle. The new technique is so cheap and easy it could literally be done in a backyard.

Starting with planks of wood a metre long and one millimetre thick, the scientists simply brushed on a solution of hydrogen peroxide using an ordinary paint brush. When left in the sun, or under a UV lamp for an hour or so, the peroxide bleached out the brown chromophores but left the lignin intact, so the wood turned white.

Next, they infused the wood with a tough transparent epoxy designed for marine use, which filled in the spaces and pores in the wood and then hardened. This made the white wood transparent.

As window material, it would be much more resistant to accidental breakage. The clear wood is lighter than glass, with better insulating properties, which is important because windows are a major source of heat loss in buildings. It also might take less energy to manufacture clear wood because there are no high temperatures involved.

Many different types of wood, from balsa to oak, can be made transparent, and it doesn’t matter if it is cut along the grain or against it. If the transparent wood is made a little thicker, it would be strong enough to become part of the structure of a building, so there could be entire transparent wooden walls.

Adele Peters in her February 2, 2021 article for Fast Company describes the work in Maryland and includes some information about other innovative and possibly sustainable uses of wood (Note: Links have been removed),

It’s [transparent wood] just one of a number of ways scientists and engineers are rethinking how we can use this renewable resource in construction. Skyscrapers made entirely out of wood are gaining popularity in cities around the world. And scientists recently discovered a technique to grow wood in a lab, opening up the possibility of using wood without having to chop down a forest.

There were three previous posts here 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

Glass-like wood windows protect against UV rays and insulate heat October 21, 2020 posting

I 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

Getting back to the latest work from the University of Maryland, here’s a link to and a citation for the paper,

Solar-assisted fabrication of large-scale, patternable transparent wood by Qinqin Xia, Chaoji Chen, Tian Li, Shuaiming He, Jinlong Gao, Xizheng Wang and Liangbing Hu. Science Advances Vol. 7, no. 5, eabd7342 DOI: 10.1126/sciadv.abd7342 Published: 27 Jan 2021

This paper is open access.

One last item, Liangbing Hu has founded a company InventWood for commercializing the work he and his colleagues have done at the University of Maryland.

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.

Desalination with nanowood

A new treatment for wood could make renewable salt-separating membranes. Courtesy: University of Maryland

An August 6, 2019 article by Adele Peters for Fast Company describes a ‘wooden’approach to water desalinization (also known as desalination),

“We are trying to develop a new type of membrane material that is nature-based,” says Z. Jason Ren, an engineering professor at Princeton University and one of the coauthors of a new paper in Science Advances about that material, which is made from wood. It’s designed for use in a process called membrane distillation, which heats up saltwater and uses pressure to force the water vapor through a membrane, leaving the salt behind and creating pure water. The membranes are usually made from a type of plastic. Using “nanowood” membranes instead can both improve the energy efficiency of the process and avoid the environmental problems of plastic.

An August 2, 2019 University of Maryland (UMD) news release provides more detail about the research,

A membrane made of a sliver of wood could be the answer to renewably sourced water cleaning. Most membranes that are currently used to distill fresh water from salty are made of polymers based on fossil fuels.

Inspired by the intricate system of water circulating in a tree, a research team from the University of Maryland, Princeton University, and the University of Colorado Boulder have figured out how to use a thin slice of wood as a membrane through which water vapor can evaporate, leaving behind salt or other contaminants.

“This work demonstrates another exciting energy/water application of nanostructured wood, as a high-performance membrane material,” said Liangbing Hu, a professor of materials science and engineering at UMD’s A. James Clark School of Engineering, who co-led the study.

The team chemically treated the wood to become hydrophobic, so that it more efficiently allows water vapor through, driven by a heat source like solar energy.

“This study discovered a new way of using wood materials’ unique properties as both an excellent insulator and water vapor transporter,” said Z. Jason Ren, a professor in environmental engineering who recently moved from CU Boulder to Princeton, and the other co-leader of the team that performed the study.

The researchers treat the wood so that it loses its lignin, the part of the wood that makes it brown and rigid, and its hemicellulose, which weaves in and out between cellulose to hold it in place. The resulting “nanowood” is treated with silane, a compound used to make silicon for computer chips. The semiconducting nature of the compound maintains the wood’s natural nanostructures of cellulose, and clings less to water vapor molecules as they pass through. Silane is also used in solar cell manufacturing.

The membrane looks like a thin piece of wood, seemingly bleached white, that is suspended above a source of water vapor. As the water heats and passes into the gas phase, the molecules are small enough to fit through the tiny channels lining the walls of the leftover cell structure. Water collected on the other side is now free of large contaminants like salt.
To test it, the researchers distilled water through it and found that it performed 1.2 times better than a conventional membrane.

“The wood membrane has very high porosity, which promotes water vapor transport and prevents heat loss,” said first author Dianxun Hou, who was a student at CU Boulder.
Inventwood, a UMD spinoff company of Hu’s research group, is working on commercializing wood based nanotechnologies.

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

Hydrophobic nanostructured wood membrane for thermally efficient distillation by Dianxun Hou, Tian Li, Xi Chen, Shuaiming He, Jiaqi Dai, Sohrab A. Mofid, Deyin Hou, Arpita Iddya, David Jassby, Ronggui Yang, Liangbing Hu, and Zhiyong Jason Ren. Science Advances 02 Aug 2019: Vol. 5, no. 8, eaaw3203 DOI: 10.1126/sciadv.aaw3203

This paper appears to be open access.

In my brief survey of the paper, I noticed that the researchers were working with cellulose nanofibrils (CNF), a term which should be familiar for anyone following the nanocellulose story, such as it.

Mixing the unmixable for all new nanoparticles

This news comes out of the University of Maryland and the discovery could led to nanoparticles that have never before been imagined. From a March 29, 2018 news item on ScienceDaily,

Making a giant leap in the ‘tiny’ field of nanoscience, a multi-institutional team of researchers is the first to create nanoscale particles composed of up to eight distinct elements generally known to be immiscible, or incapable of being mixed or blended together. The blending of multiple, unmixable elements into a unified, homogenous nanostructure, called a high entropy alloy nanoparticle, greatly expands the landscape of nanomaterials — and what we can do with them.

This research makes a significant advance on previous efforts that have typically produced nanoparticles limited to only three different elements and to structures that do not mix evenly. Essentially, it is extremely difficult to squeeze and blend different elements into individual particles at the nanoscale. The team, which includes lead researchers at University of Maryland, College Park (UMD)’s A. James Clark School of Engineering, published a peer-reviewed paper based on the research featured on the March 30 [2018] cover of Science.

A March 29, 2018 University of Maryland press release (also on EurekAlert), which originated the news item, delves further (Note: Links have been removed),

“Imagine the elements that combine to make nanoparticles as Lego building blocks. If you have only one to three colors and sizes, then you are limited by what combinations you can use and what structures you can assemble,” explains Liangbing Hu, associate professor of materials science and engineering at UMD and one of the corresponding authors of the paper. “What our team has done is essentially enlarged the toy chest in nanoparticle synthesis; now, we are able to build nanomaterials with nearly all metallic and semiconductor elements.”

The researchers say this advance in nanoscience opens vast opportunities for a wide range of applications that includes catalysis (the acceleration of a chemical reaction by a catalyst), energy storage (batteries or supercapacitors), and bio/plasmonic imaging, among others.

To create the high entropy alloy nanoparticles, the researchers employed a two-step method of flash heating followed by flash cooling. Metallic elements such as platinum, nickel, iron, cobalt, gold, copper, and others were exposed to a rapid thermal shock of approximately 3,000 degrees Fahrenheit, or about half the temperature of the sun, for 0.055 seconds. The extremely high temperature resulted in uniform mixtures of the multiple elements. The subsequent rapid cooling (more than 100,000 degrees Fahrenheit per second) stabilized the newly mixed elements into the uniform nanomaterial.

“Our method is simple, but one that nobody else has applied to the creation of nanoparticles. By using a physical science approach, rather than a traditional chemistry approach, we have achieved something unprecedented,” says Yonggang Yao, a Ph.D. student at UMD and one of the lead authors of the paper.

To demonstrate one potential use of the nanoparticles, the research team used them as advanced catalysts for ammonia oxidation, which is a key step in the production of nitric acid (a liquid acid that is used in the production of ammonium nitrate for fertilizers, making plastics, and in the manufacturing of dyes). They were able to achieve 100 percent oxidation of ammonia and 99 percent selectivity toward desired products with the high entropy alloy nanoparticles, proving their ability as highly efficient catalysts.

Yao says another potential use of the nanoparticles as catalysts could be the generation of chemicals or fuels from carbon dioxide.

“The potential applications for high entropy alloy nanoparticles are not limited to the field of catalysis. With cross-discipline curiosity, the demonstrated applications of these particles will become even more widespread,” says Steven D. Lacey, a Ph.D. student at UMD and also one of the lead authors of the paper.

This research was performed through a multi-institutional collaboration of Prof. Liangbing Hu’s group at the University of Maryland, College Park; Prof. Reza Shahbazian-Yassar’s group at University of Illinois at Chicago; Prof. Ju Li’s group at the Massachusetts Institute of Technology; Prof. Chao Wang’s group at Johns Hopkins University; and Prof. Michael Zachariah’s group at the University of Maryland, College Park.

What outside experts are saying about this research:

“This is quite amazing; Dr. Hu creatively came up with this powerful technique, carbo-thermal shock synthesis, to produce high entropy alloys of up to eight different elements in a single nanoparticle. This is indeed unthinkable for bulk materials synthesis. This is yet another beautiful example of nanoscience!,” says Peidong Yang, the S.K. and Angela Chan Distinguished Professor of Energy and professor of chemistry at the University of California, Berkeley and member of the American Academy of Arts and Sciences.

“This discovery opens many new directions. There are simulation opportunities to understand the electronic structure of the various compositions and phases that are important for the next generation of catalyst design. Also, finding correlations among synthesis routes, composition, and phase structure and performance enables a paradigm shift toward guided synthesis,” says George Crabtree, Argonne Distinguished Fellow and director of the Joint Center for Energy Storage Research at Argonne National Laboratory.

More from the research coauthors:

“Understanding the atomic order and crystalline structure in these multi-element nanoparticles reveals how the synthesis can be tuned to optimize their performance. It would be quite interesting to further explore the underlying atomistic mechanisms of the nucleation and growth of high entropy alloy nanoparticle,” says Reza Shahbazian-Yassar, associate professor at the University of Illinois at Chicago and a corresponding author of the paper.

“Carbon metabolism drives ‘living’ metal catalysts that frequently move around, split, or merge, resulting in a nanoparticle size distribution that’s far from the ordinary, and highly tunable,” says Ju Li, professor at the Massachusetts Institute of Technology and a corresponding author of the paper.

“This method enables new combinations of metals that do not exist in nature and do not otherwise go together. It enables robust tuning of the composition of catalytic materials to optimize the activity, selectivity, and stability, and the application will be very broad in energy conversions and chemical transformations,” says Chao Wang, assistant professor of chemical and biomolecular engineering at Johns Hopkins University and one of the study’s authors.

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

Carbothermal shock synthesis of high-entropy-alloy nanoparticles by Yonggang Yao, Zhennan Huang, Pengfei Xie, Steven D. Lacey, Rohit Jiji Jacob, Hua Xie, Fengjuan Chen, Anmin Nie, Tiancheng Pu, Miles Rehwoldt, Daiwei Yu, Michael R. Zachariah, Chao Wang, Reza Shahbazian-Yassar, Ju Li, Liangbing Hu. Science 30 Mar 2018: Vol. 359, Issue 6383, pp. 1489-1494 DOI: 10.1126/science.aan5412

This paper is behind a paywall.

Wood’s natural nanotechnology

“Wood’s natural nanotechnology: is an unusual term and it comes at the end of this February 7, 2018 University of Maryland (US) news release about a technique which will make wood stronger than titanium alloy,

Engineers at the University of Maryland in College Park have found a way to make wood more than ten times times stronger and tougher than before, creating a natural substance that is stronger than titanium alloy.

“This new way to treat wood makes it twelve times stronger than natural wood and ten times tougher,” said Liangbing Hu, the leader of the team that did the research, to be published on Thursday [February 7, 2018] in the journal Nature. “This could be a competitor to steel or even titanium alloys, it is so strong and durable. It’s also comparable to carbon fiber, but much less expensive.” Hu is an associate professor of materials science and engineering and a member of the Maryland Energy Innovation Institute.

“It is both strong and tough, which is a combination not usually found in nature,” said Teng Li, the co-leader of the team and the Samuel P. Langley associate professor of mechanical engineering at the University of Maryland. His team measured the dense wood’s mechanical properties.  “It is as strong as steel, but six times lighter. It takes 10 times more energy to fracture than natural wood. It can even be bent and molded at the beginning of the process.”

The team’s process begins by removing the wood’s lignin, the part of the wood that makes it both rigid and brown in color. Then it is compressed under mild heat, at about 150 F. This causes the cellulose fibers to become very tightly packed. Any defects like holes or knots are crushed together.  The treatment process was extended a little further with a coat of paint.

The scientists found that the wood’s fibers are pressed together so tightly that they can form strong hydrogen bonds, like a crowd of people who can’t budge – who are also holding hands. The compression makes the wood five times thinner than its original size.

The team also tested the material by shooting a bullet-like projectile at it. Unlike natural wood, which was blown straight through, the fully treated wood actually stopped the projectile partway through.

“Soft woods like pine or balsa, which grow fast and are more environmentally friendly, could replace slower-growing but denser woods like teak, in furniture or buildings,” Hu said.

“The paper provides a highly promising route to the design of light weight high performance structural materials, with tremendous potential for a broad range of applications where high strength, large toughness and superior ballistic resistance are desired, “ said Dr. Huajian Gao, a professor at Brown University, who was not involved in the study. “It is particularly exciting to note that the method is versatile for various species of wood and fairly easy to implement.”

“This kind of wood could be used in cars, airplanes, buildings – any application where steel is used,” Hu said.

“The two-step process reported in this paper achieves exceptionally high strength, much beyond what [is] reported in the literature,” said Dr. Zhigang Suo, a professor of mechanics and materials at Harvard University, also not involved with the study. “Given the abundance of wood, as well as other cellulose-rich plants, this paper inspires imagination.”

“The most outstanding observation, in my view, is the existence of a limiting concentration of lignin, the glue between wood cells, to maximize the mechanical performance of the densified wood. Too little or too much removal lower the strength compared to a maximum value achieved at intermediate or partial lignin removal. This reveals the subtle balance between hydrogen bonding and the adhesion imparted by such polyphenolic compound. Moreover, of outstanding interest, is the fact that that wood densification leads to both, increased strength and toughness, two properties that usually offset each other,” said Orlando J. Rojas, a professor at Aalto University in Finland.

Hu’s research has explored the capacities of wood’s natural nanotechnology [emphasis mine]. They previously made a range of emerging technologies out of nanocellulose related materials: (1) super clear paper for replacing plastic; (2) photonic paper for improving solar cell efficiency by 30%; (3) a battery and a supercapacitor out of wood; (4) a battery from a leaf; (5) transparent wood for energy efficient buildings; (6) solar water desalination for drinking and specifically filtering out toxic dyes. These wood-based emerging technologies are being commercialized through a UMD spinoff company, Inventwood LLC.

At a guess, “wood’s natural nanotechnology” refers to the properties of wood and other forms of cellulose at the nanoscale.

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

Processing bulk natural wood into a high-performance structural material by Jianwei Song, Chaoji Chen, Shuze Zhu, Mingwei Zhu, Jiaqi Dai, Upamanyu Ray, Yiju Li, Yudi Kuang, Yongfeng Li, Nelson Quispe, Yonggang Yao, Amy Gong, Ulrich H. Leiste, Hugh A. Bruck, J. Y. Zhu, Azhar Vellore, Heng Li, Marilyn L. Minus, Zheng Jia, Ashlie Martini, Teng Li, & Liangbing Hu. Nature volume 554, pages 224–228 (08 February 2018) doi:10.1038/nature25476 Published online: 07 February 2018

This paper is behind a paywall.

h/t Feb. 7, 2018 news item on Nanowerk and, finally, you can find out more about the wood-based emerging technologies being commcercialized by the University of Maryland here on the Inventwood website.

Transparent wood more efficient than glass in windows?

University of Maryland researchers are suggesting that transparent wood could be more energy efficient than glass. An Aug. 16, 2016 news item on ScienceDaily describes the research,

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.

An Aug. 16, 2016 University of Maryland news release (also on EurekAlert) which originated the news item, explains further,

In a paper just published in the peer-reviewed journal Advanced Energy Materials, 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 an image illustrating the research,

Caption: This is a wood composite as an energy efficient building material: Guided sunlight transmission and effective thermal insulation. Credit: University of Maryland and Advanced Energy Materials

Caption: This is a wood composite as an energy efficient building material: Guided sunlight transmission and effective thermal insulation. Credit: University of Maryland and Advanced Energy Materials

I have written about transparent wood twice before. There’s this April 1, 2016 posting about the work at the KTH Institute (Sweden) and a May 11, 2016 posting about some earlier work at the University of Maryland.

Here’s a link and a citation for the latest from the University of Maryland,

Wood Composite as an Energy Efficient Building Material: Guided Sunlight Transmittance and Effective Thermal Insulation by Tian Li, Mingwei Zhu, Zhi Yang, Jianwei Song, Jiaqi Dai, Yonggang Yao, Wei Luo, Glenn Pastel, Bao Yang, and Liangbing Hu. Advanced Energy Materials Version of Record online: 11 AUG 2016

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

University of Maryland looks into transparent wood

Is transparent wood becoming the material du jour? Following on the heels of my April 1, 2016 post about transparent wood and the KTH Royal Institute of Technology (Sweden), there’s a May 6, 2016 news item on ScienceDaily about the material and a team at the University of Maryland,

Researchers at the University of Maryland have made a block of linden wood transparent, which they say will be useful in fancy building materials and in light-based electronics systems.

Materials scientist Liangbing Hu and his team at the University of Maryland, College Park, have removed the molecule in wood, lignin, that makes it rigid and dark in color. They left behind the colorless cellulose cell structures, filled them with epoxy, and came up with a version of the wood that is mostly see-thru.

I wonder if this is the type of material that might be used in structures like the proposed Center of Nanoscience and Nanotechnology at Tel Aviv University building (my May 9, 2016 posting about a building design that features no doors or windows)?

Regardless, there’s more about this latest transparent wood in a May 5, 2016 Tufts University news release, which originated the news item,

Remember “xylem” and “phloem” from grade-school science class? These structures pass water and nutrients up and down the tree. Hu and his colleagues see these as vertically aligned channels in the wood, a naturally-grown structure that can be used to pass light along, after the wood has been treated.

The resulting three-inch block of wood had both high transparency—the quality of being see-thru—and high haze—the quality of scattering light. This would be useful, said Hu, in making devices comfortable to look at. It would also help solar cells trap light; light could easily enter through the transparent function, but the high haze would keep the light bouncing around near where it would be absorbed by the solar panel.

They compared how the materials performed and how light worked its way through the wood when they sliced it two ways: one with the grain of the wood, so that the channels passed through the longest dimension of the block. And they also tried slicing it against the grain, so that the channels passed through the shortest dimension of the block.

The short channel wood proved slightly stronger and a little less brittle. But though the natural component making the wood strong had been removed, the addition of the epoxy made the wood four to six times tougher than the untreated version.

Then they investigated how the different directions of the wood affected the way the light passed through it. When laid down on top of a grid, both kinds of wood showed the lines clearly. When lifted just a touch above the grid, the long-channel wood still showed the grid, just a little bit more blurry. But the short channel wood, when lifted those same few millimeters, made the grid completely invisible.

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

Highly Anisotropic, Highly Transparent Wood Composites by Mingwei Zhu, Jianwei Song, Tian Li, Amy Gong, Yanbin Wang, Jiaqi Dai, Yonggang Yao, Wei Luo, Doug Henderson, and Liangbing Hu. Advanced Materials DOI: 10.1002/adma.201600427 Article first published online: 4 MAY 2016

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

‘Beleafing’ in magic; a new type of battery

A Jan. 28, 2016 news item on ScienceDaily announces the ‘beleaf’,

Scientists have a new recipe for batteries: Bake a leaf, and add sodium. They used a carbonized oak leaf, pumped full of sodium, as a demonstration battery’s negative terminal, or anode, according to a paper published yesterday in the journal ACS Applied Materials Interfaces.

Scientists baked a leaf to demonstrate a battery. Credit: Image courtesy of Maryland NanoCenter

Scientists baked a leaf to demonstrate a battery.
Credit: Image courtesy of Maryland NanoCenter

A Jan. ??, 2016 Maryland NanoCenter (University of Maryland) news release, which originated the news item, provides more information about the nature (pun intended) of the research,

“Leaves are so abundant. All we had to do was pick one up off the ground here on campus,” said Hongbian Li, a visiting professor at the University of Maryland’s department of materials science and engineering and one of the main authors of the paper. Li is a member of the faculty at the National Center for Nanoscience and Technology in Beijing, China.

Other studies have shown that melon skin, banana peels and peat moss can be used in this way, but a leaf needs less preparation.

The scientists are trying to make a battery using sodium where most rechargeable batteries sold today use lithium. Sodium would hold more charge, but can’t handle as many charge-and-discharge cycles as lithium can.

One of the roadblocks has been finding an anode material that is compatible with sodium, which is slightly larger than lithium. Some scientists have explored graphene, dotted with various materials to attract and retain the sodium, but these are time consuming and expensive to produce.  In this case, they simply heated the leaf for an hour at 1,000 degrees C (don’t try this at home) to burn off all but the underlying carbon structure.

The lower side of the maple [?] leaf is studded with pores for the leaf to absorb water. In this new design, the pores absorb the sodium electrolyte. At the top, the layers of carbon that made the leaf tough become sheets of nanostructured carbon to absorb the sodium that carries the charge.

“The natural shape of a leaf already matches a battery’s needs: a low surface area, which decreases defects; a lot of small structures packed closely together, which maximizes space; and internal structures of the right size and shape to be used with sodium electrolyte,” said Fei Shen, a visiting student in the department of materials science and engineering and the other main author of the paper.

“We have tried other natural materials, such as wood fiber, to make a battery,” said Liangbing Hu, an assistant professor of materials science and engineering. “A leaf is designed by nature to store energy for later use, and using leaves in this way could make large-scale storage environmentally friendly.”

The next step, Hu said, is “to investigate different types of leaves to find the best thickness, structure and flexibility” for electrical energy storage.  The researchers have no plans to commercialize at this time.

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

Carbonized-leaf Membrane with Anisotropic Surfaces for Sodium-ion Battery by Hongbian Li, Fei Shen, Wei Luo, Jiaqi Dai, Xiaogang Han, Yanan Chen, Yonggang Yao, Hongli Zhu, Kun Fu, Emily Hitz, and Liangbing Hu. ACS Appl. Mater. Interfaces, 2016, 8 (3), pp 2204–2210 DOI: 10.1021/acsami.5b10875 Publication Date (Web): January 4, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Replacing metal with nanocellulose paper

The quest to find uses for nanocellulose materials has taken a step forward with some work coming from the University of Maryland (US). From a July 24, 2015 news item on Nanowerk,

Researchers at the University of Maryland recently discovered that paper made of cellulose fibers is tougher and stronger the smaller the fibers get … . For a long time, engineers have sought a material that is both strong (resistant to non-recoverable deformation) and tough (tolerant of damage).

“Strength and toughness are often exclusive to each other,” said Teng Li, associate professor of mechanical engineering at UMD. “For example, a stronger material tends to be brittle, like cast iron or diamond.”

A July 23, 2015 University of Maryland news release, which originated the news item, provides details about the thinking which buttresses this research along with some details about the research itself,

The UMD team pursued the development of a strong and tough material by exploring the mechanical properties of cellulose, the most abundant renewable bio-resource on Earth. Researchers made papers with several sizes of cellulose fibers – all too small for the eye to see – ranging in size from about 30 micrometers to 10 nanometers. The paper made of 10-nanometer-thick fibers was 40 times tougher and 130 times stronger than regular notebook paper, which is made of cellulose fibers a thousand times larger.

“These findings could lead to a new class of high performance engineering materials that are both strong and tough, a Holy Grail in materials design,” said Li.

High performance yet lightweight cellulose-based materials might one day replace conventional structural materials (i.e. metals) in applications where weight is important. This could lead, for example, to more energy efficient and “green” vehicles. In addition, team members say, transparent cellulose nanopaper may become feasible as a functional substrate in flexible electronics, resulting in paper electronics, printable solar cells and flexible displays that could radically change many aspects of daily life.

Cellulose fibers can easily form many hydrogen bonds. Once broken, the hydrogen bonds can reform on their own—giving the material a ‘self-healing’ quality. The UMD discovered that the smaller the cellulose fibers, the more hydrogen bonds per square area. This means paper made of very small fibers can both hold together better and re-form more quickly, which is the key for cellulose nanopaper to be both strong and tough.

“It is helpful to know why cellulose nanopaper is both strong and tough, especially when the underlying reason is also applicable to many other materials,” said Liangbing Hu, assistant professor of materials science at UMD.

To confirm, the researchers tried a similar experiment using carbon nanotubes that were similar in size to the cellulose fibers. The carbon nanotubes had much weaker bonds holding them together, so under tension they did not hold together as well. Paper made of carbon nanotubes is weak, though individually nanotubes are arguably the strongest material ever made.

One possible future direction for the research is the improvement of the mechanical performance of carbon nanotube paper.

“Paper made of a network of carbon nanotubes is much weaker than expected,” said Li. “Indeed, it has been a grand challenge to translate the superb properties of carbon nanotubes at nanoscale to macroscale. Our research findings shed light on a viable approach to addressing this challenge and achieving carbon nanotube paper that is both strong and tough.”

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

Anomalous scaling law of strength and toughness of cellulose nanopaper by Hongli Zhu, Shuze Zhu, Zheng Jia, Sepideh Parvinian, Yuanyuan Li, Oeyvind Vaaland, Liangbing Hu, and Teng Li. PNAS (Proceedings of the National Academy of Sciences) July 21, 2015 vol. 112 no. 29 doi: 10.1073/pnas.1502870112

This paper is behind a paywall.

There is a lot of research on applications for nanocellulose, everywhere it seems, except Canada, which at one time was a leader in the business of producing cellulose nanocrystals (CNC).

Here’s a sampling of some of my most recent posts on nanocellulose,

Nanocellulose as a biosensor (July 28, 2015)

Microscopy, Paper and Fibre Research Institute (Norway), and nanocellulose (July 8, 2015)

Nanocellulose markets report released (June 5, 2015; US market research)

New US platform for nanocellulose and occupational health and safety research (June 1, 2015; Note: As you find new applications, you need to concern yourself with occupational health and safety.)

‘Green’, flexible electronics with nanocellulose materials (May 26, 2015; research from China)

Treating municipal wastewater and dirty industry byproducts with nanocellulose-based filters (Dec. 23, 2014; research from Sweden)

Nanocellulose and an intensity of structural colour (June 16, 2014; research about replacing toxic pigments with structural colour from the UK)

I ask again, where are the Canadians? If anybody has an answer, please let me know.