Through alizarin-hectorite pigments: Influence of organofunctionalization on fading

International audienceIn this work, hectorite/alizarin pigments were prepared at pH 9 and 12. Hectorite was initially modified with cetyltrimethylammonium and pectine to produce organo-hectorites. The influence of organo-hectorite on the stabilization of alizarin was evaluated. X-ray diffraction suggested the formation of exfoliated/delaminated structures after organofunctionalization of the hectorite. For raw hectorite and their derivatives with pectin, the formation of hybrid pigments was confirmed by infrared spectroscopy. Thermogravimetry curves confirm the hectorite organofunctionalization and that the alizarin loading was higher at pH 12. The hybrids prepared at pH 12 show more photostability than ones prepared at pH 9. This behavior was probably due to the total deprotonation of dye molecules, which promoted better interactions between the hosts and the guests