07215 IUPAC Gold Book - ionomer cluster 10.1351/goldbook.IT07215 IT07215 current 1 Ionic aggregate, in a polymer matrix of low polarity, formed through interactions of ionomer multiplets. The mobility of the polymer segments surrounding the multiplets is reduced relative to that of bulk material. With increasing ion content, the number density of the ionomer multiplets increases, leading to overlapping of the restricted mobility regions around the multiplets and the formation of clusters. Typically, an ionomer exhibits two glass transition temperatures (\(T_{\rm{g}}\)), one for the non-polar matrix and the other for clusters. glass transition https://goldbook.iupac.org//terms/view/G02640 ionomer https://goldbook.iupac.org//terms/view/I03229 mobility https://goldbook.iupac.org//terms/view/M03955 number density https://goldbook.iupac.org//terms/view/N04262 polarity https://goldbook.iupac.org//terms/view/P04710 PAC, 2006, 78, 2067. 'Terminology of polymers containing ionizable or ionic groups and of polymers containing ions (IUPAC Recommendations 2006)' on page 2072 (https://doi.org/10.1351/pac200678112067) https://goldbook.iupac.org/terms/view/IT07215/html https://goldbook.iupac.org/terms/view/IT07215/json https://goldbook.iupac.org/terms/view/IT07215/plain Citation: 'ionomer cluster' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.IT07215 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. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . 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. 2026-04-21T01:17:38+00:00