Induction of CD in some anionic dyes by cationic chitosan

✍ Scribed by Medini Kanta Pal; Prasun Kumar Pal

• Book ID: 101719729
• Publisher: Wiley (John Wiley & Sons)
• Year: 1990
• Tongue: English
• Weight: 316 KB
• Volume: 29
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360290409

✦ Synopsis

Abstract

Chitosan can be converted into a polycation by dissolving it in an acid, and this polycation (I) induces blue‐shifted metachromasia in suitable anionic dyes, C.I. acid red 88 and C.I. acid orange 7, after reacting with the dyes with 1 : 1 stoichiometry (P/D). Both these dye–polymer systems exhibit strong biphasic CD in the visible range. Biphasic CD, as well as blue‐shifted metachromasia, indicates strong dye–dye interactions in these systems. Monophasic CD are observed only in conditions where metachromasia is partially disrupted due to poor dye–dye interactions.

The 2~1~‐helical conformation, as confirmed for the present polymer chitin as well as for neutral chitosan, seems to be inadequate in explaining the observed results with (I).