Tag Archives: carbon nanotube sponges

Nanosponges clean up spilled oil and release the oil for future use

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The nanosponges that have been developed by a joint team of Rice University and Penn State University researchers look pretty exciting (wish I could write a better headline about them). Here’s the researcher describing them,

I find the idea that the sponges can be reused and the oil still put to use quite compelling. From the April 16, 2012 news item on Nanowerk,

… Daniel Hashim, a graduate student in the Rice lab of materials scientist Pulickel Ajayan, said the blocks are both superhydrophobic (they hate water, so they float really well) and oleophilic (they love oil). The nanosponges, which are more than 99 percent air, also conduct electricity and can easily be manipulated with magnets.

…

To demonstrate, Hashim dropped the sponge into a dish of water with used motor oil floating on top. The sponge soaked it up. He then put a match to the material, burned off the oil and returned the sponge to the water to absorb more. The robust sponge can be used repeatedly and stands up to abuse; he said a sample remained elastic after about 10,000 compressions in the lab. The sponge can also store the oil for later retrieval, he said.

“These samples can be made pretty large and can be easily scaled up,” said Hashim, holding a half-inch square block of billions of nanotubes. “They’re super-low density, so the available volume is large. That’s why the uptake of oil can be so high.” He said the sponges described in the paper can absorb more than a hundred times their weight in oil.

Nanosponges have been made from carbon nan0tubes before now (from the Feb. 8, 2010 article by Michael Berger on Nanowerk),

Carbon nanotubes (CNTs) are ‘strange’ nanostructures in a sense that they have both high mechanical strength and extreme flexibility. Deforming a carbon nanotube into any shape would not easily break the structure, and it recovers to original morphology in perfect manner. Researchers in China are exploiting this phenomenon by making CNT sponges consisting of a large amount of interconnected nanotubes, thus showing a combination of useful properties such as high porosity, super elasticity, robustness, and little weight (1% of water density).

The nanotube sponges not only show exciting properties as a porous material but they also are very promising to be used practically in a short time. The production method is simple and scalable, the cost is low, and the sponges can find immediate use in many fields related to water purification.

“We hope to give an example to industry that this sponge is a real thing they can prepare at low cost, make versatile products with high performance, and solve environmental problems utilizing nanotechnology,” [says] Anyuan Cao, a professor in the Department of Advanced Materials and Nanotechnology at Peking University …

The difference between the nanosponges made in 2010 and the ones made in 2012 is the fabrication process. From the April 16, 2012 news item on Nanowerk,

Ajayan, Rice’s Benjamin M. and Mary Greenwood Anderson Professor in Mechanical Engineering and Materials Science and of chemistry, said multiwalled carbon nanotubes grown on a substrate via chemical vapor deposition usually stand up straight without any real connections to their neighbors. But the boron-introduced defects induced the nanotubes to bond at the atomic level, which tangled them into a complex network. Nanotube sponges with oil-absorbing potential have been made before (see paper in Advanced Materials: “Carbon Nanotube Sponges”), but this is the first time the covalent junctions between nanotubes in such solids have been convincingly demonstrated, he said.

“The interactions happen as they grow, and the material comes out of the furnace as a solid,” Ajayan said. [emphasis mine] “People have made nanotube solids via post-growth processing but without proper covalent connections. The advantage here is that the material is directly created during growth and comes out as a cross-linked porous network.

By comparison, the team in China used this process (from the Feb. 8, 2012 article),

The scientists synthesized the sponges by a chemical vapor deposition (CVD) process during which the CNTs (multi-walled nanotubes with diameters in the range of 30 to 50nm and lengths of tens to hundreds of micrometers,) self-assembled into a porous, interconnected, three-dimensional framework.

The research team had collaborators from the US, Mexico, Japan, Spain, and Belgium. From the April 16, 2012 news release on EurekAlert,

When he was an undergraduate student of Ajayan’s at Rensselaer Polytechnic Institute, Hashim and his classmates discovered hints of a topological solution to the problem while participating in a National Science Foundation exchange program at the Institute of Scientific Research and Technology (IPICYT) in San Luis Potosí, Mexico. The paper’s co-author, Mauricio Terrones, a professor of physics, materials science and engineering at Penn State University with an appointment at Shinshu University, Japan, led a nanotechnology lab there.

“Our goal was to find a way to make three-dimensional networks of these carbon nanotubes that would form a macroscale fabric — a spongy block of nanotubes that would be big and thick enough to be used to clean up oil spills and to perform other tasks,” Terrones said. “We realized that the trick was adding boron — a chemical element next to carbon on the periodic table — because boron helps to trigger the interconnections of the material. To add the boron, we used very high temperatures and we then ‘knitted’ the substance into the nanotube fabric.”

For anyone who would like to read further about this work (from the April 16, 2012 news release on EurekAlert),

The paper’s co-authors are Narayanan Narayanan, Myung Gwan Hahm, Joseph Suttle and Robert Vajtai, all of Rice; Jose Romo-Herrera of the University of Vigo, Spain; David Cullen and Bobby Sumpter of Oak Ridge National Laboratory, Oak Ridge, Tenn.; Peter Lezzi and Vincent Meunier of Rensselaer Polytechnic Institute; Doug Kelkhoff of the University of Illinois at Urbana-Champaign; E. Muñoz-Sandoval of the Instituto de Microelectrónica de Madrid; Sabyasachi Ganguli and Ajit Roy of the Air Force Research Laboratory, Dayton, Ohio (on loan from IPICYT); David Smith of Arizona State University; and Humberto Terrones of Oak Ridge National Lab and the Université Catholique de Louvain, Belgium.

The article is titled, Covalently bonded three-dimensional carbon nanotube solids via boron induced nanojunctions, and has been published as an open access article in Nature’s Scientific Reports.

I did mention the nanosponges developed in China in my Feb. 9, 2010 posting.

Patents kill innovation?; nanosponges and spinning carbon nanotubes in China; Google and the universal translator

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There’s an article about patents in The Economist online that provokes a question that’s not broached in the article. Here’s the thesis,

Most economists would argue that, without a patent system, even fewer inventions would lead to successful innovations, and those that did would be kept secret for far longer in order to maximise returns. But what if patents actually discourage the combining and recombining of inventions to yield new products and processes—as has happened in biotechnology, genetics and other disciplines?

Here’s the logical next question. If you accept the notion that patents kill innovation (or hinder it mightily) than how can the number of patents that are registered by any one country be used as a standard measure of scientific progress as per the 2009 OECD Science, Technology and Industry Scoreboard (my post about Canada’s low patent score here)?

Thanks to Techdirt for pointing me to The Economist article (go here to see their take) and to the Brad Feld posting (go here to see their take) about biotech innovation and patents. From Feld’s posting,

Regularly, patent advocates tell me how important patents are for the biotech and life science industries.  However, there apparently is academic research in the works that shows that patents actually slow down innovation in biotech.  The specific example we discussed was that there is increasing evidence that when a professor or company gets a patent in the field of genetics research, other researchers simply stop doing work in that specific area.  As a result, the number of researchers on a particular topic decreases, especially if the patent is broad.  It’s not hard to theorize that this results in less innovation around this area over time.

Feld goes on cite a few academics who write about patents and their impact on innovation. His main interest is not biotech but software which brings me back to the article in The Economist and a ‘weirdity’ at the end.

An end to frivolous patents for business processes will be a blessing to online commerce. Meanwhile, the loss of patent protection for software could make programmers realise at last that they have more in common with authors, artists, publishers and musicians than they ever had with molecular architects and chip designers. In short, they produce expressions of ideas that are eminently copyrightable.

That could be good news for innovation. After all, who in his right mind would seek a lousy old patent offering a mere 20 years of protection when copyright can provide monopoly rights for up to 70 years after the author’s death? That one fact alone could spur more innovation than all the tinkering attempted so far.

I understand that the author is being satirical, unfortunately, the copyright side of intellectual property law is at least as crazy as the patent side and this falls a little flat for me.

Michael Berger over at Nanowerk has devoted a couple of spotlight items (in depth articles) to innovations in China over the last few days. First there were the carbon nanotube sponges,

Carbon nanotubes (CNTs) are ‘strange’ nanostructures in a sense that they have both high mechanical strength and extreme flexibility. Deforming a carbon nanotube into any shape would not easily break the structure, and it recovers to original morphology in perfect manner. Researchers in China are exploiting this phenomenon by making CNT sponges consisting of a large amount of interconnected nanotubes, thus showing a combination of useful properties such as high porosity, super elasticity, robustness, and little weight (1% of water density). The nanotube sponges not only show exciting properties as a porous material but they also are very promising to be used practically in a short time. The production method is simple and scalable, the cost is low, and the sponges can find immediate use in many fields related to water purification.

Then today, there was an article on spinning carbon nanotube yarns,

“While the development of a continuous and weavable pure carbon nanotube yarn remains a major challenge in the fabrications, CNT yarns so far obtained from the different processes are monolithic in structure,” Ya-Li Li, a professor in the Nanomaterials and PDCs Group at the Key Laboratory of Advanced Ceramics and Machining Technology at Tianjin University in PR China, explains to Nanowerk. “We have now been able to demonstrate the fabrication of a novel continuous yarn of CNTs with a multiple-layer structure by the chemical vapor deposition (CVD) spinning process. The yarn consists of multiple monolayers of CNTs concentrically assembled in seamless tubules along the yarn axis.”

While I’ve seen a number of articles proclaiming China’s increasing  presence in many scientific fields, including nanotechnology, this is the first time I’ve seen articles that probe beyond a basic description of published studies in language that is still accessible, i.e., you don’t need a specialist degree to read the material. It certainly helps to contextualize the statistics and other data about China’s published studies.

Kit Eaton’s article (Will Google’s Translator Phone lead us to Babylon or Babble On?) in Fast Company touches on, biblical times (Tower of Babel), Star Trek (universal translator) and linguistics, how could I resist?

Google’s revealed it’s working on extensions to its smartphone voice-control powers, debuted in the Nexus One, that’ll automatically translate between languages. It’s the stuff of pure utopian science fiction. But is it a good idea?

While Eaton makes some other sci fi references that I’m not particularly familiar with such as Douglas Adams’ Babel Fish (which in turn references the Tower of Babel), her point is clear: there can be unintended consequences (a concept from Max Weber, if I recall rightly) to new inventions/innovations.

…  For example, if Google’s device succeeds, and is useful and ubiquitous (in other words, nearly everyone ends up using it, or a competing service)–nobody would need learn a foreign language. “Hooray!” you may be thinking, but this isn’t necessarily a good thing. Because language plays such a fundamental part in connecting each of us as thinking creatures with the world around us, that the subtle nuances of language (which are different even in similar tongues, say the Latin-derived Spanish and Portuguese) actually shape how we think about the world. Learning something of how somebody else speaks from a foreign country actually helps you to understand their mindset a little. And if the average Joe on the street never learns a foreign language anymore (because it’s a very tricky thing to do, and Google’s just doing it for you, so why bother?) then that subtle understanding will be lost.

In the discussion about  “… the subtle nuances of language shaping how we think …” Eaton is referring to the Sapir-Whorf hypothesis. Interestingly, some of the traditional linguistics departments in universities have resisted this hypothesis (I first learned about it in a mid-1980s communications course where we focused on semiotics).

On purely speculative terms, I could see two other ways for a universal translator to have unintended consequences. First, if something can’t be translated, it could disappear. Second, if a translatable version of your native language should emerge, people could break up into smaller subgroups to create more languages and more barriers to understanding. Eaton’s article definitely provoked some thinking for me this morning.

I did mention that I’d be posting the Geisler interview article later this week and I may have been a little optimistic as I’m having some difficulties chasing down a few details. In short, it’s on its way.