Maya Blue, an Ancient Guest-Host Pigment: Synthesis and Models

The blue of the ancient Maya civilization, Maya blue (MB), can be an excellent example for the introduction of composite materials at high school or at first-year college levels. In addition to the synthesis of MB, made according to an old recipe, a simple model of beads and LEDs has been developed mimicking this organic-inorganic hybrid (a mixture of the organic dye indigo with a clay: palygorskite). This allows teaching-learning activities where the instructor can (i) explore the rich history of MB (including that of indigo); (ii) perform the synthesis of MB in the lab; (iii) reveal the remarkable stability of MB; and finally (iv) lead the student to understand the interactions between indigo individual molecules and the clay host in MB using an imaginative and simple model.