Excluded volume of a segment

{
  "id": "MLC-T-CHM-004199",
  "term": "Excluded volume of a segment",
  "field": "Chemistry",
  "definition": "The effective volume from which one chain segment keeps all other segments out, whether they belong to the same chain or to other chains. It depends on the free energy of mixing of polymer and solvent rather than on the geometric volume of the segment, so it is positive in a good solvent, zero at the theta point and negative in a poor solvent. A positive value expands the coil beyond its unperturbed size.",
  "subject": "Polymer",
  "references": [
    "Purple Book, 1st ed., p. 58 (http://old.iupac.org/publications/books/author/metanomski.html)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/excluded-volume-of-a-segment/"
}