from the I[m-waiting-for-it-to-be-transparent,-too dept.
Penn Engineers Develop Ultrathin, Ultralight 'Nanocardboard'
[A] team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square centimeter of nanocardboard weighs less than a thousandth of a gram and can spring back into shape after being bent in half.
Nanocardboard is made out of an aluminum oxide film with a thickness of tens of nanometers, forming a hollow plate with a height of tens of microns. Its sandwich structure, similar to that of corrugated cardboard, makes it more than ten thousand times as stiff as a solid plate of the same mass.
Nanocardboard's stiffness-to-weight ratio makes it ideal for aerospace and microrobotic applications, where every gram counts. In addition to unprecedented mechanical properties, nanocardboard is a supreme thermal insulator, as it mostly consists of empty space.
Future work will explore an intriguing phenomenon that results from a combination of properties: shining a light on a piece of nanocardboard allows it to levitate. Heat from the light creates a difference in temperatures between the two sides of the plate, which pushes a current of air molecules out through the bottom.
Nanocardboard as a nanoscale analog of hollow sandwich plates (open, DOI: 10.1038/s41467-018-06818-6) (DX)
(Score: 2) by Unixnut on Friday November 09 2018, @07:38AM (4 children)
> A square centimeter of nanocardboard weighs less than a thousandth of a gram and can spring back into shape after being bent in half.
> Its sandwich structure, similar to that of corrugated cardboard, makes it more than ten thousand times as stiff as a solid plate of the same mass.
> Nanocardboard's stiffness-to-weight ratio makes it ideal for aerospace and microrobotic applications, where every gram counts.
> In addition to unprecedented mechanical properties, nanocardboard is a supreme thermal insulator, as it mostly consists of empty space.
> shining a light on a piece of nanocardboard allows it to levitate. Heat from the light creates a difference in temperatures between the two sides of the plate, which pushes a current of air molecules out through the bottom.
Heh, reading the above, it sounds very much like the description of materials found after a UFO crash. I don't remember which conspiracy site I was on when I was reading about it, but the above sounds very much like what was described (looked like aluminium, very light, very strong, very good insulator, and can spring back into shape when bent).
So, either we have caught up with the aliens independently, or we've been doing some reverse engineering :-P
Either way, this sounds like a very impressive material. Now just to see how long it takes to go from the lab to industry and end users (at an affordable cost).
(Score: 2) by c0lo on Friday November 09 2018, @08:28AM (3 children)
Effing expensive. The Al oxide is deposited on a nanoscale patterned piece of silicon. Not only that the matrix itself is going to be expensive, but to get your 'corrugated Al oxide sheet' out, that matrix is chemically dissolved after deposition.
Some hundred of dollars per cm^2 or so.
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by PiMuNu on Friday November 09 2018, @10:07AM (2 children)
Cheaper than the latest round of Eurofighter (or US equivalent)?
(Score: 3, Interesting) by c0lo on Friday November 09 2018, @12:28PM (1 child)
Certainly more expensive than the Wagyu porterhouse I had last weekend (point: comparing the cost of nanostructured aluminium oxide and the steak has as much relevance as comparing the same with the cost of fighter planes**).
A valid comparison:
- Eurofighter - double engine, started in 1982, total development programme cost £37B and the entire Eurofighter fleet achieved over 200,000 flight hours in Sep 2013 with combat operation missions under its belt
- F35 - single engine, started in 1992, estimated cost to $1.46T for the entire life of the project by 2070, development still not ready in 2016 (engine redesign) and there may be other surprises requiring redesign today and, yes!, the entire worldwide fleet of F35 scored exactly 3 combat missions: 2 by Israelis in May 2018 and 1 by US in Sep 2018.
---
**
If you think that the characteristics of a single nanosheet scale proportionally if you stack more of them - so that the Al-oxide nanonsheets can be use to build fighter planes, let me give you an example.
You know about how wonderful graphene is [graphenea.com]: high electrical conductivity (with electrons and holes having zero effective mass), "strongest material ever discovered, with an ultimate tensile strength of 130,000,000,000 Pascals".
Well, stack some million of graphene sheets one on top of the other and what you get is graphite. You know, the stuff the pencil lead is made of - decent but not extraordinary conductivity, don't ever think of building something that requires high mechanical strength or flexibility.
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by PiMuNu on Monday November 12 2018, @11:24AM
I agree, but I think you missed my point. Sure, this stuff can be pretty expensive, but then some of the applications that are relevant are also expensive.
I make no comment as to whether it can be scaled appropriately (and so on).
(Score: 2) by MichaelDavidCrawford on Friday November 09 2018, @12:53PM
Fat shaming kills
Yes I Have No Bananas. [gofundme.com]
(Score: 1, Interesting) by Anonymous Coward on Friday November 09 2018, @01:33PM (2 children)
The truly excellent paper (with both micro and macro properties described) mentions that one application might be for micro flyers, since this material outperforms currently used composites. Just don't mistake that micro flying-camera-platform for an insect, if you swat one of these with your hand it's likely to give you a nasty cut.
While solar sails are mentioned as another application, making a solar sail using semiconductor manufacturing processes sounds like an interesting problem. The authors mention scaling up from finger-nail sizes to 6" wafer size (150mm), but do not mention how to join many of them together to make a large structure. I don't think aluminum oxide is going to be weldable...maybe the material can be fabricated with a clever design at the edges so they interlock/snap together.
(Score: 2) by HiThere on Friday November 09 2018, @05:30PM (1 child)
I can think of a lot of useful applications. But one characteristic not mentioned is how it is much more susceptible to corrosion. This will need to be taken into account in any actual application. (Some applications may even find that a useful characteristic.)
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 0) by Anonymous Coward on Saturday November 10 2018, @03:40AM
> ...more susceptible to corrosion.
Are you sure about that? Seems to me that Al2O3 (aluminum oxide) is pretty darn stable, already fully oxidized into a ceramic and with a very high melting point.
(Score: 0) by Anonymous Coward on Friday November 09 2018, @06:35PM
Appearance on 'Ancient Aliens' and/or 'Alien Files' and/or 'UFO Hunters' in 3...2...1...
Nah, Aliens mate, Aliens....secret reverse engineered Roswell Tech finally revealed...with lame cover story..
(Beer, I need beer, lots of beer.....)