Substantivity

http://chlorhexidinefacts.com/mechanism-of-action.html Protein bound chlorhexidine releases slowly leading to prolonged activity. This phenomenon is known as substantivity and allows for a longer duration of antimicrobial action against a broad spectrum of bacteria and fungi.

Source: wiktionary

The term substantivity refers to the ability of a dye to transfer from a solution onto a textile fiber and to "set".

Source: wiktionary