Are Kuhn Lengths Determined by the Number of Bonds?

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In summary, the values of nb chosen in the text for polyethylene and poly(cis-isoprene) are 18 and 24 bonds respectively, based on the concept of Kuhn statistical length. The Kuhn statistical length for polyethylene is 12A° and for poly(cis-isoprene) is 9A°. This implies that the Kuhn lengths are fixed and determined by the number of bonds chosen to work with.
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chemie
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Okay so I know that they aren't but this thing i am reading makes it appear that they are fixed.
QUOTE from the text:

"The values of nb(for the statistical segment) chosen in this work are 18 bonds for
polyethylene and 24 bonds (a hexamer) for poly(cisisoprene).
One reason for these choices of nb involves the concept of the Kuhn statistical length, which, for polyethylene is ,12A°and ,9 A° for poly(cis-isoprene)".

So is he trying to say that Kuhn lenghts are fixed?

I don't understand. because kuhn lenghts follow this formula: ,h=nL and <h^2>=nL^2 ...which means it depends on the number of bonds 'n' that we chose to work with in the first place.
 
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well i was wrong they are indeed fixed.
 

FAQ: Are Kuhn Lengths Determined by the Number of Bonds?

1. What are Kuhn lengths?

Kuhn lengths refer to a unit of measurement used in polymer science to describe the length of a polymer chain. It is typically measured in nanometers (nm) and is used to understand the physical properties of polymers.

2. Are Kuhn lengths fixed?

No, Kuhn lengths are not fixed. They can vary depending on the polymer's composition, molecular weight, and environmental conditions such as temperature and solvent interactions.

3. How are Kuhn lengths determined?

Kuhn lengths are typically determined experimentally using techniques such as light scattering, small-angle X-ray scattering, or nuclear magnetic resonance (NMR) spectroscopy.

4. Why are Kuhn lengths important?

Kuhn lengths are important because they provide valuable information about the conformation and flexibility of polymer chains. This information is crucial in understanding the behavior of polymers in various applications, such as in materials science and biotechnology.

5. Can Kuhn lengths be used to compare different polymers?

Yes, Kuhn lengths can be used to compare different polymers. However, it is important to note that the comparison should be made between polymers with similar molecular weights and environmental conditions to accurately assess their relative flexibility.

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