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posted by janrinok on Wednesday December 06 2017, @10:02PM   Printer-friendly
from the tiny-prisoners-beware dept.

For decades, scientists have been trying to make a true molecular chain: a repeated set of tiny rings interlocked together. In a study in Science published online Nov. 30, University of Chicago researchers announced the first confirmed method to craft such a molecular chain.

Many molecules described as "linked" are joined with fixed covalent bonds—not two freely moving interlocked rings. The distinction makes a big difference when it comes to how the chain moves.

"Think about dangling a silver chain onto your palm: It collapses easily into a flat pool and can flow off your hand, much different from a string of fixed beads," said Stuart Rowan, a professor at UChicago's Institute for Molecular Engineering and Department of Chemistry and lead author on the paper.

The longer interlocked chains could make materials or machines with intriguing properties, researchers said. Polymers—materials made of repeated units joined together—are extremely useful in everyday life, making up everything from plastics to proteins; and this new way to combine the repeat units could open new avenues in engineering.

[...] "A metal rod is rigid, but a metal chain made of the same material is very flexible," said UChicago postdoctoral researcher Qiong Wu, the first author on the paper. "By keeping the same chemical composition but changing the architecture, you can dramatically change the material's behavior."

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  • (Score: 4, Interesting) by DannyB on Wednesday December 06 2017, @10:22PM (3 children)

    by DannyB (5839) Subscriber Badge on Wednesday December 06 2017, @10:22PM (#606443)

    The wording could be more clear. I am still left wondering. So are these chains rigid? That is, really more like a stick than a flexible chain?

    I don't see anything in TFA about how current materials might have new properties.

    Even tiny rigid sticks of material at near molecular level could have interesting properties. Imagine a mass of these rigid chains. If they aren't bonded together what you have could be more like a liquid than a solid. But not really a liquid. It might behave more like fine sand, but far finer particles. Now imagine if something caused all of these rigid chains to align on one axis, would that suddenly make a bowl full of this material suddenly shrink in physical volume while keeping the same weight / mass? Would the shrunken form have otherwise different properties?

    If the rigid chains could all align somehow along one axis, would this result in extreme rigidity?

    TFA leaves me with more questions than answers. Assuming I even correctly understood what they mean by "chains".

    • (Score: 0) by Anonymous Coward on Wednesday December 06 2017, @11:12PM (1 child)

      by Anonymous Coward on Wednesday December 06 2017, @11:12PM (#606466)

      Pinch the tips of your pointer finger and thumb on the left hand together to form a horizontal loop, then take your right hand and pinch the same fingers together except forming a vertical loop. Now you have two independent loops.

      Next unpinch your right hand for moment and hold it so it forms a vertical C shape. Then move the thumb aspect of the left hand loop to be above the trapeziometacarpal joint of the right thumb (bottom of the C). Now pinch your right hand fingers together again, the tips should touch in the center of the horizontal loop formed by your left hand. You won't be able to separate the two loops without unpinching your fingers. This is what they meany by a chain: two or more independent (we are pretending the fingers aren't connected via your arms and torso) loops that are connected to form an object with new properties, but not melded together.

      • (Score: 2) by tangomargarine on Thursday December 07 2017, @04:31PM

        by tangomargarine (667) on Thursday December 07 2017, @04:31PM (#606853)

        I don't think Danny was unclear on the vernacular definition of "chain," but whether that's the one the article is using.

        I'm not really sure why though, since the article goes to great lengths to establish that fact.

        Because they are so vanishingly small—each loop is about a nanometer in diameter, less than a hundred atoms across—the team spent a lot of time proving the chain really had freely rotating loops. But a combination of experimental and computational techniques convinced the researchers they were real.

        "Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
    • (Score: 0) by Anonymous Coward on Thursday December 07 2017, @02:06AM

      by Anonymous Coward on Thursday December 07 2017, @02:06AM (#606551)

      That was my first thought when I read this.

      I don't know how strong this chain's bonds actually are, but if it has more strength than the average intermolecular bonds, it might be usable as a method to cut through other materials, while also being flexible enough to coil up into a suitably dense handle without danger when it isn't under tension.

  • (Score: 1, Funny) by Anonymous Coward on Wednesday December 06 2017, @10:28PM

    by Anonymous Coward on Wednesday December 06 2017, @10:28PM (#606448)

    A condom small enough for Trump.

  • (Score: 3, Funny) by Revek on Wednesday December 06 2017, @10:29PM (1 child)

    by Revek (5022) on Wednesday December 06 2017, @10:29PM (#606452)

    The tiniest violin can't be far behind.

    • (Score: 2) by bob_super on Wednesday December 06 2017, @11:26PM

      by bob_super (1357) on Wednesday December 06 2017, @11:26PM (#606470)

      I'm worried that's just a leash for the most ridiculous purse dog yet