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Wednesday, March 23, 2016

Shrinky Dinks: Crumpled Graphene

 
      "Brown University researchers have developed a method for making super-wrinkled and super-crumpled sheets of the nanomaterial graphene. The research shows that the topography can enhance some of graphene’s already interesting properties."




      "Crumple a piece of paper and it’s probably destined for the trash can, but new research shows that repeatedly crumpling sheets of the nanomaterial graphene can actually enhance some of its properties. In some cases, the more crumpled the better."



      "The research by engineers from Brown University shows that graphene, wrinkled and crumpled in a multi-step process, becomes significantly better at repelling water—a property that could be useful in making self-cleaning surfaces. Crumpled graphene also has enhanced electrochemical properties, which could make it more useful as electrodes in batteries and fuel cells."

        The research is published in the journal Advanced Materials.
         
       In keeping with our honey-comb theme of late, graphene is an allotrope of carbon in the form of a two-dimensional, atomic-scale, honey-comb lattice in which one atom forms each vertex. 




      It is the basic structural element of other allotropes, including graphite, charcoal, and carbon nanotubes.

      "Researchers deposited layers of graphene oxide onto shrink films—polymer membranes that shrink when heated (kids may know these as Shrinky Dinks). As the films shrink, the graphene on top is compressed, causing it to wrinkle and crumple. To see what kind of structures they could create, the researchers compressed same graphene sheets multiple times. After the first shrink, the film was dissolved away, and the graphene was placed in a new film to be shrunk again."




      "The researchers experimented with different configurations in the successive generations of shrinking. For example, sometimes they clamped opposite ends of the films, which caused them to shrink only along one axis. Clamped films yielded graphene sheets with periodic, basically parallel wrinkles across its surface. Unclamped films shrank in two dimensions, both length- and width-wise, creating a graphene surface that was crumpled in random shapes."


      "They showed that a highly crumpled graphene surface becomes superhydrophobic—able to resist wetting by water. When water touches a hydrophobic surface, it beads up and rolls off. When the contact angle of those water beads with an underlying surface exceeds 160 degrees—meaning very little of the water bead’s surface touches the material—the material is said to be superhydrophobic."





       "The team also showed that crumpling could enhance the electrochemical behaviors of graphene, which could be useful in next-generation energy storage and generation. The research showed that crumpled graphene used as a battery electrode had as much as a 400% increase in electrochemical current density over flat graphene sheets. That increase in current density could make for vastly more efficient batteries."

           Happy crumpling from blizzardy Denver!

Steph







44 comments:

  1. Any idea why graphene becomes so rabidly hydrophobic when crumpled?

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    1. Spoken like a true hexagonophile! I was wondering whether it had to do with the wrinkles providing fewer points of contact between the water droplet and the graphene sheet.

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    2. Probably wise to avoid commenting on "rabidly hydrophobic"....

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    3. Especially this time of year ;-).

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  2. Using the contact angle to define hydrophobicity is unsatisfying. We need a unit of measure. I propose the ducksback.

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    Replies
    1. Alas, Cuprinol seems to have trademarked the name for a line of sealers, at least in the UK.

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  3. Replies
    1. "Ducksback" should be in all dictionaries, jan. But Steph's challenge appears not to be hydrophobicity, but "niphophobicity"! (see: "III. Alphabetical Listing of Selected Greek arid Latin Terms Useful to Public Health" (L=Latin, G=Greek)" in this link.

      LegoLikeSnowOffA"Dach's"Back

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  4. Replies
    1. I've had baking projects produce similar results.

      Don't put too much basalt in your granite!

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    2. We do a fun igneous fudge project with fast (obsidian) and slow (granite) cooling. . .

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  5. I have considered that I may be suffering from a terminal case of witzelsucht.

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    1. Witzelsucht! Such witz! Finally, I have a name for with what I am afflicted! I don't get the buffet table joke though. But I do indeed think that all my puns/jokes/quips/bon mots/mal mots are hilarious.

      LegoPrefersACaseOfWitzelsuchtToACaseOfLeinenkugels

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    2. So that's where this comes from! Agreed, Jan and Lego.

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    3. So that's where this comes from! Agreed, Jan and Lego.

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    4. You can say that again, Steph... Oh wait, I guess you did.

      LegoOhWaitIGuessYouDid

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    5. Haha, Lego!

      Why doesn't autocorrect know I want jan not Jan when I've written it that way so often?!

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    6. It's a good thing Witzel stopped.

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  6. Do you endorse this product?

    There was an ad for it on this blog.

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    Replies
    1. Hmmm, Paul, I do not. Colloidal Ag, huh?!

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    2. Hmmm, I think the ad I'm now getting is targeted at ME, rather than the intersection of ME with THIS BLOG.

      (It's for my local gas company.)

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    3. Lexus seems to like me.

      Go figure.

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    4. It's a quack treatment for syphilis, among other things.

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    5. Whadya know?

      Yeah, sometimes the ads seem personal, sometimes personal plus blog, and sometimes blog only. I wonder how that algorithm works. . .

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    6. I seem to be stuck in a natural gas loop.

      Is this the panacea?

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    7. Oh, it's gonna be hard to unsee that first "this," Paul.

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  7. Up for a little HANAMI? I could endorse that!

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    Replies
    1. Must be the regional bias that made them omit the annual Cherry Blossom Festival in Newark's beautiful Branch Brook Park. On the other hand, it's missing from Wikipedia's Hanami page, too. Gotta fix that one of these days.

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    2. Looks lovely! So glad the park is open to all. Palisade, CO, orchards are exquisite, too, but not public spaces.

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    3. "Newark's beautiful"

      whodathunkit?

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    4. Newark: not just a gray airport . . .

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    5. I'm not claiming the whole city's lovely. But on a sunny Spring weekend, with 4,000 cherry trees in bloom, and the park filled with an amazing variety of people, speaking dozens of languages, and all enjoying the beauty, it's really pretty nice.

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    6. Updated Wikipedia's hanami page.

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  8. I don't have an opinion about this; I should probably crunch some numbers first.

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  9. New post on "White-Nose Bat Syndrome Crosses the Rocky Mountains close to Seattle, Washington, USA" is now up.

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