co-solvency
in polymers
https://doi.org/10.1351/goldbook.C01361
The dissolution of a polymer in a solvent comprising more than one component, each component of which by itself is a non-solvent for the polymer.
Source:
Purple Book, 1
st
ed., p. 60 (http://old.iupac.org/publications/books/author/metanomski.html)