Title: Indigo/sepiolite nanohybrids: stability of natural pigments inspired by Maya blue

Authors: Françoise Giulieri; Sonia Ovarlez; Anne-Marie Chaze

Addresses: Laboratoire Chimie des Matériaux Organiques et Métalliques, Université Nice-Sophia Antipolis, Parc Valrose, 06108 Nice cedex 2, France. ' Laboratoire Chimie des Matériaux Organiques et Métalliques, Université Nice-Sophia Antipolis, Parc Valrose, 06108 Nice cedex 2, France. ' Laboratoire Chimie des Matériaux Organiques et Métalliques, Université Nice-Sophia Antipolis, Parc Valrose, 06108 Nice cedex 2, France

Abstract: Maya blue is formed from insertion of indigo into palygorskite and sepiolite. Sepiolite and palygorskite are porous fibrous clays. Controlling the insertion, location and organisation of organic molecules in the cavities of nanotubes associated with the release or stability of these molecules is a crucial challenge in the evolution towards unusual properties in nanotechnologies. We validate simple FTIR analyses able to determine the location of indigo in or outside the pores of the fibres. Then, we compare the stability of indigo/palygorskite and indigo/sepiolite systems obtained from similar formulations. The heating treatment is stopped when all indigo is complexed with the clay. We show that in these conditions indigo/palygorskite is more stable than indigo/sepiolite. The formation of stable pigment is more complicated for indigo-sepiolite than for indigo-palygorskite.

Keywords: nanohybrids; indigo; sepiolite; palygorskite; nanopigments; porous clays; fibrous clays; natural pigments; Maya blue; nanotechnology; organic molecules; nanotubes.

DOI: 10.1504/IJNT.2012.045334

International Journal of Nanotechnology, 2012 Vol.9 No.3/4/5/6/7, pp.605 - 617

Received: 08 May 2021
Accepted: 12 May 2021

Published online: 02 Feb 2012 *

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