Term: phase domain
https://doi.org/10.1351/goldbook.PT07286

Definition:
Region of a material that is uniform in chemical composition and physical state.

Notes:
0) A phase in a multiphase material can form domains differing in size.
1) The term 'domain' may be qualified by the adjective microscopic or nanoscopic or the prefix @M03894@- or @N04082@- according to the size of the linear dimensions of the domain.
2) The prefixes @M03894@-, and @N04082@- are frequently incorrectly used to qualify the term 'phase' instead of the term 'domain'; hence, 'microphase domain', and 'nanophase domain' are often used. The correct terminology that should be used is phase microdomain and phase nanodomain.

Related Terms:
1) micro (http://doi.org/10.1351/goldbook.M03894).
2) nano (http://doi.org/10.1351/goldbook.N04082).

Source: PAC, 2004, 76, 1985. 'Definition of terms related to polymer blends, composites, and multiphase polymeric materials (IUPAC Recommendations 2004)' on page 2001 (https://doi.org/10.1351/pac200476111985)

Citation: 'phase domain' 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.PT07286

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