New Research on Untying Knots in Polymers - Comments

In summary, the article discusses the potential benefits of knots in polymers, and how they can create stability and enhance functionality.
  • #1
klotza
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Greg Bernhardt submitted a new PF Insights post

New Research on Untying Knots in Polymers
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  • #2
That was fun to read. Good article.

When you remove the stretching forces, do they immediately re-knot?

Can you calculate the potential energy of the configurations? Is a knotted state lower energy than straight?
 
  • #3
Good question. The lowest energy state of a polymer is a random coil, that is the one that maximizes entropy. When you stretch a polymer and let it relax, it returns to the coiled state as entropy increases (this is also why rubber is elastic). However, if there's no knot it is unlikely (but not impossible) for knots to spontaneously form as it relaxes.

A polymer with a knot is thought to have a higher free energy than one without a knot (there's more configurations without a knot than with a knot, so unknot has higher entropy). What has been theorized is that knots are metastable, meaning there is an equilibrium size for the knot once it exists, and it is unlikely to expand to much bigger than that, so the molecule will remain knotted for a long time, until it diffuses to the end of the molecule and unties. There might also be scenarios in which knots are favourable, like a molecule under extreme confinement (the DNA of a virus is an example).
 
  • #4
Do the knots put extra stress at particular bonds that might make the bond break? If the knotted state is stable, that suggests they don't break.

How about non-DNA practical applications?
 
  • #5
They do. You can try tying a cooked spaghetti noodle into a knot and pulling on the ends. The noodle will break at the knot. All this stuff about thermodynamic stability though basically assumes that the length is constant (no breaking or growing).

There are lots of things that knots are useful for, but I'm not sure my research really improved any of those.
 
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1. How does this new research contribute to our understanding of knotting in polymers?

This new research provides a deeper understanding of the mechanisms involved in the formation and untying of knots in polymers. It also sheds light on the factors that influence knot formation and stability in polymers.

2. What methods were used in this research to study knotting in polymers?

The researchers used computer simulations and experimental techniques such as atomic force microscopy and gel electrophoresis to study knotting in polymers. These methods allowed for a detailed analysis of the structures and dynamics of knotted polymers.

3. What are the potential applications of this research?

This research has potential applications in various fields, such as materials science, biotechnology, and nanotechnology. Understanding knotting in polymers can help in the design of new materials with improved properties and in the development of more efficient drug delivery systems.

4. How does this research contribute to the development of new untangling techniques?

By providing a better understanding of the mechanisms involved in knotting and untying polymers, this research can aid in the development of new untangling techniques. These techniques can be useful in various industries, such as manufacturing, where tangled polymers can cause production delays and decrease product quality.

5. What are some potential future directions for this research?

One potential future direction for this research is to study knotting in more complex polymer systems, such as branched polymers or polymers with different topologies. Additionally, investigating the effects of different environmental conditions on knotting and untying in polymers could provide valuable insights for real-world applications.

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