Response to “C. Tsiantos, M. Tsampodimou, G.H. Kacandes, M. Sánchez del Río, V. Gionis, G.D. Chryssikos. Comment to the paper: Identification of indigoid compounds present in archaeological Maya blue by pyrolysis-silylation-gas chromatography–mass spectrometry (M.T. Doménech-Carbó, L. Osete-Cortina, A. Doménech-Carbó, M.L. Vázquez de Agredos-Pascual, C. Vidal-Lorenzo, J. Anal. Appl. Pyrol. 105 (2014) 355–362)”

Ceramics from the Alcazar Palace in Seville (Spain) dated between the 11th and 15th centuries: Compositions, technological features and degradation processes

“…An iridescent layer is produced by lixiviation of the glaze based on an ionic interchange between H + from the medium and the Ca 2+ and Pb 2+ cations from the bulk glaze. P certainly derives from the burial environment which penetrated in the hydrated structure of the glaze [66][67][68][69][70]. The enrichement of P, Pb and Ca and release of other elements triggered the local precipitation of secondary phases which depend of pH, Eh and concentration of the different ions in the solution.…”

Water-dispersible and stable fluorescent Maya Blue-like pigments

“…Thus, PR 31 was chosen as the representative HFOP in this study. LRD could successfully bring indigo, the main organic component in Maya Blue, into the aqueous phases according to Lezhnina et al 29 Whereas the marriage between 20 LRD and PR 31 via solid-state grinding generates not only waterdispersible but also stable fluorescent pigments, which we term Maya-Blue like LRD/PR 31 pigments. The representative LRD/PR 31 pigment is highly water-dispersible after ultrasonication and the concentration of PR 31 in water is as high 25 as 9.97 mg/mL which is much higher than the LRD/indigo dispersion (0.2 mg/mL) produced by Lezhninaet al 29 The LRD/PR 31aqueous suspension shows excellent fluorescence and is stable in room conditions for over 4 months without any sediment.…”

“…2c, d and Movie S1). Moreover, stable aqueous suspension 20 of LRD/PR 31 can be easily formed by stirring and ultrasonication in deionized water. Once encountered with water, the stacked platelets of LRD/PR 31 automatically exfoliate into individual platelets via electrostatic repulsion to form a network structure.…”

“…Bringing these hydrophobic 20 compounds into aqueous solutions is of general interests for the scientific community and the industrial area. Hydrophobic fluorescent organic pigments (HFOPs) have attracted much attention in diverse fields, e.g., coatings, inks and plastics, owing to their bright color and light tone.…”

“…16 There is also a viewpoint that different types of interactions are present in the 65 structure of Maya Blue. 20 In addition, for some researchers, the stability of Maya Blue depends more on steric shielding than on hydrogen bonding. 21 The definite position of indigo molecules in the palygorskite is still in dispute.…”