Term: micelle https://doi.org/10.1351/goldbook.M03889 Definition: Surfactants in solution are often association colloids, that is, they tend to form aggregates of colloidal dimensions, which exist in equilibrium with the molecules or ions from which they are formed. Such aggregates are termed micelles. Related Terms: 1) inverted micelle (http://doi.org/10.1351/goldbook.I03151). 2) surfactants (http://doi.org/10.1351/goldbook.S06194). 3) association (http://doi.org/10.1351/goldbook.A00472). 4) colloidal (http://doi.org/10.1351/goldbook.C01172). Source: PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1140 (https://doi.org/10.1351/pac199466051077) Citation: 'micelle' 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.M03889 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.