Process by which a substance becomes transferred into pre-existing spaces of molecular dimensions in a second substance.
The term as defined here is specific to polymer science. An alternative definition of 'intercalation' applies in some other fields of chemistry.
PAC, 2004, 76, 1985
(Definition of terms related to polymer blends, composites, and multiphase polymeric materials (IUPAC Recommendations 2004))
on page 1991
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. doi:10.1351/goldbook