Facile color regulation of organic/inorganic hybrid pigments combining with palygorskite and CoNi layered double hydroxides

Abstract

Maya blue or Maya blue-like pigments are famous for their vivid colors and good environmental stability, but their colors are dependent on the natural or synthetic organic dyes, thus the color system is not complete due to the limited types of organic dyes. In this study, the novel and multicolor organic/inorganic hybrid pigments with the controlled colors were facilely fabricated by wet-method adsorption of cationic dyes using palygorskite followed by one-step loading and intercalation of CoNi layered double hydroxides (CoNi LDHs) with anionic dyes. The colors, compositions, and morphologies of hybrid pigments were analyzed by combining with different characterization techniques. The results indicated that the colors of hybrid pigments were determined with the colors of the involved cationic dyes, anionic dyes and CoNi LDHs, which could be accurately designed by adjusting the colors and contents of cationic and anionic dyes. What's more, the samples loaded with the sensing dye of methyl orange exhibited intelligent behavior at different pH values (2.5–5.5). Incorporation of palygorskite and CoNi LDHs obviously enhanced the thermal stability of the organic dyes. Based on the synergistic effects between organic and inorganic compositions of hybrid pigments, incorporation of hybrid pigments enhanced the mechanical properties of chitosan composite film with the desired color, and thus the as-prepared hybrid pigments could be served as promising colorant and reinforced materials for coloring and reinforcing of polymeric packing materials.