Title: Kirkwood–Riseman theory
Long Title: IUPAC Gold Book - Kirkwood–Riseman theory
DOI: 10.1351/goldbook.12263
Status: current

Definition
Theory, based on the pearl-necklace model, that describes the translational diffusive and viscous flows of an isolated linear macromolecule in solution in the theta state and accounts for the gradual change from free-draining behaviour at lower molecular weights to impermeable behaviour at higher molecular weights.

Note
The Kirkwood–Riseman theory is usually applied in the impermeable limit when it essentially relates the equivalent hydrodynamic radius to the root-mean-square unperturbed radius of gyration, \(\lt\!s_{\circ}^{2}\!\gt\), with \[r_{D} = 0.675 \lt\!s_{\circ}^{2}\!\gt^{1/2}\] and \[r_{\eta} = 0.256 \lt\!s_{\circ}^{2}\!\gt^{1/2}\] where \(r_{D}\) and \(r_{\eta}\) are the equivalent hydrodynamic radii in translational diffusive flow and viscous flow.

Related Terms
- equivalent hydrodynamic radius: https://goldbook.iupac.org//terms/view/12258
- free-draining: https://goldbook.iupac.org//terms/view/12254
- impermeable: https://goldbook.iupac.org//terms/view/12255
- pearl-necklace model: https://goldbook.iupac.org//terms/view/12262
- root-mean-square unperturbed radius of gyration: https://goldbook.iupac.org//terms/view/12193

Source
- PAC, 2015, 87, 71. 'Definitions of terms relating to individual macromolecules, macromolecular assemblies, polymer solutions, and amorphous bulk polymers (IUPAC Recommendations 2014)' on page 104 (https://doi.org/10.1515/pac-2013-0201)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/12263/html
- json: https://goldbook.iupac.org/terms/view/12263/json
- xml: https://goldbook.iupac.org/terms/view/12263/xml

Citation: Citation: 'Kirkwood–Riseman theory' 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.12263
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Accessed: 2026-04-18T08:18:02+00:00