Mordant

Mordant red 19 is a typical mordant dye. Like many mordant dyes, it features the azo group (RN=NR) and various sites for chelating to metal cations.
A French Indienne, a printed or painted textile in the manner of Indian productions, which used mordants to fix the dyes

A mordant or dye fixative is a substance used to set (i.e., bind) dyes on fabrics. It does this by forming a coordination complex with the dye, which then attaches to the fabric (or tissue).[1] It may be used for dyeing fabrics or for intensifying stains in cell or tissue preparations. Although mordants are still used, especially by small batch dyers, they have been largely displaced in industry by directs.[2]

The term mordant comes from the Latin mordere, "to bite". In the past, it was thought that a mordant helped the dye "bite" onto the fiber so that it would hold fast during washing. A mordant is often a polyvalent metal ion, and one example is chromium (III).[3] The resulting coordination complex of dye and ion is colloidal and can be either acidic or alkaline.

  1. ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "mordant". doi:10.1351/goldbook.M04029
  2. ^ Hunger, Klaus; Mischke, Peter; Rieper, Wolfgang; Zhang, Shufen} (March 8, 2019). Azo Dyes, 5. Developing Dyes. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA. pp. 1–19. doi:10.1002/14356007.o03_o09.pub2. ISBN 9783527306732. OCLC 46878292. {{cite book}}: |work= ignored (help)
  3. ^ Llewellyn, Bryan D. (May 2005). "Stain Theory – How mordants work". Archived from the original on May 20, 2016.