Term: characteristic ratio
https://doi.org/10.1351/goldbook.C00982

Definition:
The ratio of the mean-square end-to-end distance, < r2 >0, of a linear polymer chain in a theta state to N · L 2, where N is the number of rigid sections in the main chain, each of length L; if all of the rigid sections are not of equal length, the mean-square value of L is used, i.e. \[L^{2}=\sum _{i}\frac{L_{i}^{\bar{2}}}{N}\] In simple single-strand chains, the bonds are taken as the rigid sections. The recommended symbol is: CN (C∞ when N → ∞).

Related Terms:
1) linear polymer (http://doi.org/10.1351/goldbook.L03556).

Source: Purple Book, 1st ed., p. 49 (http://old.iupac.org/publications/books/author/metanomski.html)

Citation: 'characteristic ratio' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.C00982

License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms.

Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.