Saponite-anthocyanin derivatives: The role of organoclays in pigment photostability

• Published in: Applied clay science Vol. 191; p. 105604
• Main Authors: Lima, Luciano C.B., Silva, Fabrícia C., Silva-Filho, Edson C., Fonseca, Maria G., Zhuang, Guanzheng, Jaber, Maguy
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.06.2020; Elsevier
• Subjects: Anthocyanin; Chemical Sciences; Chemical stability; Color change; Hybrid pigment; Material chemistry; Natural dye; Organo-functionalization; Organo-saponite; Photostability; Saponite; Anthocyanin; Saponite; Natural dye; Hybrid pigment; Photostability; Chemical stability; Organo-functionalization; Color change; Organo-saponite
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2020.105604

Hybrid pigments based on organo-saponite (cetyltrimethyl ammonium bromide (CTAB-Sap) and a commercial anthocyanin (ACN) dye, Crystal Red Grape, were prepared. The interactions between organic dye guest and hosts (including saponite and organo-saponite) were investigated by X-ray diffraction, transmission electron microscopy and Fourier transform infrared spectroscopy. The pigments exhibit different colors function of their host-guest interactions. The blue color of organo-clay-anthocyanin indicates the stabilization of quinoidal base form of the dye. The hybrids have good stability against visible light irradiation and basic pH conditions. These dyed materials are environmentally friendly and can be promising candidates in different application fields. [Display omitted] •Anthocyanin stabilization was carried out by adsorption on unmodified and modified saponite.•Modified saponite stabilized the blue quinoidal base form of anthocyanin while the unmodified intercalated the red flavylium cation structure.•The resulting hybrid exhibited reversible acid/base chromism from blue to red and vice-versa.