Tong Lin and his research team at Deakin University in Australia have developed a coating that is super hydrophopic, i. e., water repellent. Actually, it repels more than just water, from the April 25, 2012 news item on Nanowerk,
Scientists are reporting development and successful testing of a fabric coating that would give new meaning to the phrase “stain-resistant” — a coating that would take an active role in sloughing off grease, dirt, strong acids and other gunk. The report, which shows that the coating is even more water-repellent than car wax or Teflon, appears in ACS’ journal Langmuir (“Photoreactive Azido-Containing Silica Nanoparticle/Polycation Multilayers: Durable Superhydrophobic Coating on Cotton Fabrics”).
There is more information about the coating, including a video, in an April 26, 2012 article by Jason Palmer for BBC News online,
The new work hinges on what is known as layer-by-layer self-assembly – basically dipping a fabric into a solution over and over again to deposit multiple layers on it.The team from the Australian Future Fibres Research and Innovation Centre at Deakin University made their solution with tiny particles of silica – the same material as sand.
Crucially, they added a few chemical steps to coat the particles with long chemical tails ending in what are known as azido groups.
… baked under a source of UV light, the tails on the particles were made to interlink with one another, forming a far tougher structure within and across the layers.
Apparently the coating remains intact on the fibres for up to 50 laundry washings.There is more here about Dr. Lin and his work on fibres.
While searching for Tong Lin on the internet I came across a Buddhist practice, Tonglin or Tonglen.
We take it for granted most of the time. The ability to sense pressure and respond to appropriately doesn’t seem like any great gift but without it, you’d crush fragile objects or be unable to hold onto the heavy ones.
It’s this ability to sense pressure that’s a stumbling block for robotmakers who want to move robots into jobs that require some dexterity, e.g., one that could clean yours windows and your walls without damaging one or failing to clean the other.
Two research teams have recently published papers about their work on solving the ‘pressure problem’. From the article by Jason Palmer for BBC News,
The materials, which can sense pressure as sensitively and quickly as human skin, have been outlined by two groups reporting in [the journal] Nature Materials.
The skins are arrays of small pressure sensors that convert tiny changes in pressure into electrical signals.
The arrays are built into or under flexible rubber sheets that could be stretched into a variety of shapes.
The materials could be used to sheath artificial limbs or to create robots that can pick up and hold fragile objects. They could also be used to improve tools for minimally-invasive surgery.
One team is located at the University of California, Berkeley and the other at Stanford University. The Berkeley team headed by Ali Javey, associate professor of electrical engineering and computer sciences has named their artificial skin ‘e-skin’. From the article by Dan Nosowitz on the Fast Company website,
Researchers at the University of California at Berkeley, backed by DARPA funding, have come up with a thin prototype material that’s getting science nerds all in a tizzy about the future of robotics.
This material is made from germanium and silicon nanowires grown on a cylinder, then rolled around a sticky polyimide substrate. What does that get you? As CNet says, “The result was a shiny, thin, and flexible electronic material organized into a matrix of transistors, each of which with hundreds of semiconductor nanowires.”
But what takes the material to the next level is the thin layer of pressure-sensitive rubber added to the prototype’s surface, capable of measuring pressures between zero and 15 kilopascals–about the normal range of pressure for a low-intensity human activity, like, say, writing a blog post. Basically, this rubber layer turns the nanowire material into a sort of artificial skin, which is being played up as a miracle material.
As Nosowitz points out, this is a remarkable achievement and it is a first step since skin registers pressure, pain, temperature, wetness, and more. Here’s an illustration of Berkeley’s e-skin (Source: University of California Berkeley, accessed from http://berkeley.edu/news/media/releases/2010/09/12_eskin.shtml Sept. 14, 2010),
An artist’s illustration of an artificial e-skin with nanowire active matrix circuitry covering a hand. The fragile egg illustrates the functionality of the e-skin device for prosthetic and robotic applications.
The Stanford team’s approach has some similarities to the Berkeley’s (from Jason Palmer’s BBC article),
“Javey’s work is a nice demonstration of their capability in making a large array of nanowire TFTs [this film transistor],” said Zhenan Bao of Stanford University, whose group demonstrated the second approach.
The heart of Professor Bao’s devices is micro-structured rubber sheet in the middle of the TFT – effectively re-creating the functionality of the Berkeley group’s skins with less layers.
“Instead of laminating a pressure-sensitive resistor array on top of a nanowire TFT array, we made our transistors to be pressure sensitive,” Professor Bao explained to BBC News.
Here’s a short video about the Stanford team’s work (Source: Stanford University, accessed from http://news.stanford.edu/news/2010/september/sensitive-artificial-skin-091210.html Sept. 14, 2010),
Both approaches to the ‘pressure problem’ have at least one shortcoming. The Berkeley’s team’s e-skin has less sensitivity than Stanford’s while the Stanford team’s artificial skin is less flexible than e-skin as per Palmer’s BBC article. Also, I noticed that the Berkeley team at least is being funded by DARPA ([US Dept. of Defense] Defense Advanced Research Projects Agency) so I’m assuming a fair degree of military interest, which always gives me pause. Nonetheless, bravo to both teams.
HP Labs is making memristor news again. From a news item on physorg.ocm,
HP is partnering with Korean memory chip maker Hynix Semiconductor Inc. to make chips that contain memristors. Memristors are a newly discovered building block of electrical circuits.
HP built one in 2008 that confirmed what scientists had suspected for nearly 40 years but hadn’t been able to prove: that circuits have a weird, natural ability to remember things even when they’re turned off.
I don’t remember the story quite that way, i.e., “confirmed what scientists had suspected for nearly 40 years” as I recall the theory that R. Stanley William (the HP Labs team leader) cites is from Dr. Leon Chua circa 1971 and was almost forgotten. (Unbeknownst to Dr. Chua, there was a previous theorist in the 1960s who posited a similar notion which he called a memistor. See Memistors, Memristors, and the Rise of Strong Artificial Intelligence, an article by Blaise Mouttet, for a more complete history. ETA: There’s additional material from Blaise at http://www.neurdon.com/)
There’s more about HP Labs and its new partner at BBC News in an article by Jason Palmer,
Electronics giant HP has joined the world’s second-largest memory chip maker Hynix to manufacture a novel member of the electronics family.
The deal will see “memristors” – first demonstrated by HP in 2006 [I believe it was 2008] – mass produced for the first time.
Memristors promise significantly greater memory storage requiring less energy and space, and may eventually also be employed in processors.
HP says the first memristors should be widely available in about three years.
If you follow the link to the story, there’s also a brief BBC video interview with Stanley Williams.
My first 2010 story on the memristor is here and later, there’s an interview I had with Forrest H Bennet III who argues that the memristor is not a fourth element (in addition to the capacitor, resistor, and inductor) but is in fact part of an infinite table of circuit elements.
ETA: I have some additional information from the news release on the HP Labs website,
HP today announced that it has entered into a joint development agreement with Hynix Semiconductor Inc., a world leader in the manufacture of computer memory, to bring memristor technology to market.
Memristors represent a fourth basic passive circuit element. They existed only in theory until 2006 – when researchers in HP Labs’ Information and Quantum Systems Laboratory (IQSL) first intentionally demonstrated their existence.
Memory chips created with memristor technology have the potential to run considerably faster and use much less energy than Flash memory technologies, says Dr. Stanley Williams, HP Senior Fellow and IQSL founding Director.
“We believe that the memristor is a universal memory that over time could replace Flash, DRAM, and even hard drives,” he says.
Uniting HP’s world-class research and IP with a first-rate memory manufacturer will allow high-quality, memristor-based memory to be developed quickly and on a mass scale, Williams adds.
Also, the video interview with Dr. Williams is on youtube and is not a BBC video as I believed. So here’s the interview,
One of the hardest (or, as is sometimes preferred, most challenging) aspects of writing papers and doing research is keeping track of all your reference material. “Where is that quote? In which paper did I read that stereoselectivity is not an important factor in this process?” and on it goes when you’re writing. For a substantive paper you can end up with 50 or more references and I’ve seen some where there are more 100 . For a thesis or a book, you’re looking at hundreds of references.
Since the advent of computers and then the internet, the bar has risen considerably. Finding both the latest and as many references as possible is much easier online than searching library card catalogues and journal indexes manually. Correspondingly, the expectations are much higher despite the fact that new tools to access references haven’t really kept up. Yes, there are citation management systems but those are an automated version of putting your references on 3″ x 5″ cards and putting them in order (although the automated version will also spit out whichever citation format you request, which is a wonderful thing).
All of this is a preamble to an article, Science enters the age of Web 2.0, by Jason Palmer on BBC News here about some new tools that can help. From the article,
You might think that professional research scientists are at the forefront of what the newest tools of the internet can provide in terms of collaboration and the discovery of knowledge.
After all, they’re frequently plonked down in front of their computers, with all that the web has to offer them easily at hand, right?
Well, sort of.
“Scientists are all about doing new things but actually we’re very conservative about the way that we do them,” said Cameron Neylon, a senior scientist for biomolecular sciences at the Science and Technology Facilities Council.
Palmer goes on to discuss the new tools and how they help multiple researchers in varying disciplines spread out amongst several timezones to work together as well as answer some of the questions I posed earlier.