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Flexible cellulose aerogel to overcome brittleness
PopSci recently reported that a team of researchers have created a new cellulose aerogel. The researched was published in Nature Nanotechnology.
The team, composed of scientists from the Department of Fibre and Polymer Technology, Royal Institute of Technology, Stockholm, Sweden, soaked cellulose in a metal compound solution and freeze-dried it, removing all the moisture and leaving behind an aerogel in the form of solid fibers. The resultant substance was flexible, unlike typical aerogels, and could also be formed into a flat piece of magnetic nanopaper that was capable of supporting extremely heavy weight.
Researchers who developed this cellulose aerogel believe that it could find its use in fuel cells and in the study of materials science.
By now, aerogels are sort of old news in the materials science community. Although current forms have many uses, this group of scientists decided that overcoming their characteristic stiffness could open up a whole new range of uses.
When looking for a material to use to circumvent the stiffness, the authors decided to try a type of cellulose. Researchers first soaked it in a solution of two metal compounds, iron sulfate and cobalt chloride. While the cellulose soaked, tiny nanoparticles of the metals would stick to the cellulose and remain even after drying, so it could be used as a magnet if desired. Then they freeze-dried the cellulose, leaving nothing but a web of pure, solid fibers. The gel is highly porous and mostly air at this point, and yet can still sustain much weight.
Once the cellulose was freeze dried into an aerogel, the researchers found it was capable of two different applications. One involved crushing most of the air out of it, resulting in a small, strong, flat piece of magnetic “nanopaper” that could support 400,000 pounds per square inch.
But, as a regular aerogel, its properties were still highly unusual: It was flexible and could bend in half and twist easily. Normally aerogels are brittle and fracture under too much force, but the cellulose version could stand twice as much strain as a regular aerogel.
The scientists found that they could also use the flexible aerogel as a tiny sponge. Because its volume was almost 99 percent air, it could absorb water and then be wrung out, while still retaining its shape and magnetic properties. A 60 milligram patch of aerogel could hold about a gram of water.
The very fine structure of cellulose aerogel will allow it to be used in tiny pieces while retaining their characteristics-very stiff and magnetic, or magnetic, flexible, and absorbent-depending on the properties needed.
The authors speculate that their aerogel could find wide use in materials science, as its components, especially the cellulose, come pretty cheap. In the future, they predict it will play the role of a tiny actuator, or appear in microfluidic devices used in fuel cells and for studying the physics of cells.
Materials stories that missed the cut this week
At the end of each week, I end up with a list of a bunch of stories I started to write about, or started to investigate or didn’t even get that far even though the topic looked intriguing, but, I had a meeting to go to . . .
Anyway, it’s Friday, and rather than have these stories evaporate into the ether, I’ve decided to close out each week by providing some raw links to some of these orphan tales. Check ‘em out:
$18M in new DOE awards for advance materials innovations in manufacturing
Ceralink's Microwave Technology Center
The DOE is giving a total of $13 million to 48 industrial energy-efficiency R&D projects, many of which will have either a direct bearing on ceramic and cementitious materials development and manufacturing including several new opportunities for high-temperature materials applications. An additional $5 million in matching grants is being ponied up by the private sector.
The awards, part of DOE’s Industrial Technologies Program, are targeted for the “development of transformational industrial processes and technologies that can significantly reduce greenhouse gas emissions.” The ITP awards come in four topic areas:
Next Generation Manufacturing Concepts - These manufacturing concepts address the goal of reducing the energy intensity or greenhouse gas emissions of industrial systems by a minimum of 25 percent.
Energy Intensive Processes - These projects address specific technology areas that are expected to generate large energy-saving benefits across a variety of industries and transform the way major manufacturing processes use energy. The following specific technology areas are included: Reactions and Separations; High-Temperature Processing; Waste Heat Minimization and Recovery; and Sustainable Manufacturing.
Advanced Materials - These projects focus on Thermal and Degradation Resistant Materials and Materials for Energy Systems.
Industrial Greenhouse Gas Emissions Reduction - These projects address transformational technologies that offer not only carbon intensity reductions, but also absolute carbon reductions.
The list of awards is long, but here are a few highlights:
3M is getting nearly $800,000 to develop of new high-temperature low-cost ceramic media/catalyst support for use in natural gas surface combustion burners with lower NOx emissions.
Alcoa is getting $397,00 to develop a novel membrane purification cell to produce pure aluminum from recycled scrap.
Aspen Aerogels is getting $375,000 to develop a new nanoporous silica-based high-temperature aerogel for high-temperature steam and process pipes (450–650°C) to make a durable product with improved water repellency and decreased dusting).
CCS Materials Inc. is getting $382,000 to develop hydrate-free, non-Portland cement concrete for building facades. The aim, first, is to create a CO2-negative inorganic binding phase and, second, develop a method to reduce the energy required to make concrete by 60% and CO2 emissions by more than 90%. These objectives will be accomplished using a patent-pending process called low-temperature solidification.
Ceralink is getting $1.21 million for three RF and microwave-related projects. The first is to establish the manufacturing potential of RF glass lamination process (a low-energy alternative to autoclaving) for auto and solar panel glass. The other two projects involve microwave-enhanced direct cracking of hydrocarbon feedstock and energy-efficient microwave calcination of limestone.
Eaton Corp. is getting $373,000 to develop nanocoatings technology for high-contact stress environments
using new compositions (al-mag-borides) and coating methods.
Hi-Z Technology is getting $500,000 to develop and commercialize thermoelectric devices based on Si/SiGe quantum well materials as ultra-thin films that, for example, could increase the efficiency to 40% of the conversion of thermal energy in hot waste gas to electric energy.
Rive Technology Inc. is getting $762,000 for advanced nanostructured molecular sieves (mesoporous zeolite containing adsorbents) for energy-efficient industrial separation of propane from propylene.
Structured Materials Industries Inc. is getting $315,000 low cost production of InGaN for next-generation photovoltaic devices and LEDs.
UES Inc. is getting $300,000 to develop and commercialize next-generation super-hard, nano-crystalline and multilayered multifunctional coatings, with at least double service life. The coating materials include nitrides and borides and the processes include magnetron sputtering ion plating and large area filtered arc deposition.
Univ. of California, Santa Cruz is getting $348,000 to develop a transformational print-based manufacturing process for fabricating photovoltaics and solid state lighting on thin plastic substrates.
Univ. of the Pacific is getting $367,000 to research and develop a new silica-alumina based cementitious material (i.e., non-limestone) largely using coal refuse as a constituent that will be ideal for mine backfill, mine sealing and waste disposal stabilization.
CWRU’s Aeroclay aerogel has ability to soak up oil spills
I’ve written before about the work of David Schiraldi’s aerogel research group at Case Western Reserve University. With much of North and Central America focused on the BP’s oil spill in the Gulf of Mexico, it’s worth noting that Schiraldi and his team have had success in developing prototypes of special reuseable aerogel sponges for sopping up oil.
Schiraldi describes his aerogels as “aeroclays,” and they are often combinations of clay and polymers and other materials that are mixed in to add special properties. CWRU featured the oil absorbency properties of one of the aeroclay versions in a story and a short video demonstration on its website in February.
An ultra-lightweight sponge made of clay and a bit of high-grade plastic draws oil out of contaminated water but leaves the water behind.
“This particular one is oleophilic or oil-loving,” Schiraldi said. “Chemically, it hates water, loves oil: the perfect combination.”
The aeorgel can be made in granular form, in sheets or in blocks of almost any shape and is effective in fresh and saltwater or on a surface. Because absorption is a physical phenomenon, there is no chemical reaction between the material and oil. If the oil is otherwise not contaminated, it can be used.
Oil spill experts on both coasts say that the ability to squeeze out and conserve the oil is an advantage over other products currently available.
Although I haven’t found any post-BP spill comments from Schiraldi, his group back in February predicted that the aeroclay would “effectively clean up spills of all kinds of oils and solvents on factory floors and roadways, rivers and oceans.”
CWRU says it has granted a nine-month exclusive license for this and other clay-based aerogel technologies to Aeroclay Inc., a company in which Schiraldi will be chief scientific officer.
Here is a bonus video featuring Schiraldi talking about his work:
Emerging advanced ceramic materials may find use in future oil spills
Nanotube oil sponge
I am writing this post from the Tampa Bay area where the spreading Gulf of Mexico oil spill, not surprisingly, dominates the news. Several acquaintances here have asked me if there is anything in advanced ceramics and other novel materials that might be useful in future spills. Unfortunately, this is not an area I have any degree of expertise in, but we have had several posts in which the oil absorbency of a novel material was emphasized:
Aerogel’s potential to mop up oil spills
Nanogel, a branded aerogel made of modified, water-repellent silica, soaked up oil faster and in greater quantities than other materials that are typically used in wastewater filtration, according to a study published in Industrial & Engineering Chemistry Research. Boston-based Cabot Corp., which makes Nanogel, helped pay for the research and supplied the product.
Carbon nanotubes as super sponges
Chinese scientists say they have figured out a way to turn carbon nanotubes into a superabsorbing and reusable sponge for organic materials. They predict their CNT sponge material may be particularly valuable in applications such as oil spills on ocean, lake and river surfaces because the material won’t absorb water.
Aeroclay is a patented foamlike and environmentally friendly clay-based polymer. Aeroclay materials feel and act like foam, without injection of gas bubbles or environmentally unfriendly CFCs.
