Influences of micropores and water molecules in the palygorskite structure on the color and stability of Maya blue pigment
Influences of micropores and water molecules in the palygorskite structure on the color and stability of Maya blue pigment
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DOI：
10.1016/j.micromeso.2021.111615
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发表时间：
2021-12
影响因子：
5.2
通讯作者：
Guanzheng Zhuang;Li Li-Li;Mengyuan Li;Peng Yuan
中科院分区：
文献类型：
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作者：
Guanzheng Zhuang;Li Li-Li;Mengyuan Li;Peng Yuan
玛雅蓝是一种由靛蓝和微孔坡缕石组成的古老混合颜料，具有梦幻般的色调和出色的稳定性。它的致色机理和稳定机理是一个尚未解决的问题。在这项工作中，通过在180 ° C、300 ° C和570 °C下加热获得不同的坡缕石材料，以原始坡缕石作为参考。以这些坡缕石材料和固体靛蓝为原料制备了类玛雅蓝颜料。采用热分析、X射线衍射、傅里叶变换红外光谱和微孔分析等方法研究了凹凸棒石微孔结构和内部水分子的状态。通过反射光谱、CIE颜色参数以及在浓硝酸、二甲基亚砜和可见光下暴露约100年后的色差，表征了颜料的颜色特性、耐化学性和光稳定性。证实了只有将靛蓝分子插入到坡缕石的微孔中，才能制备出稳定的蓝绿色杂化色素。微孔内的沸石水分子应该被去除，因为它们阻碍了靛蓝分子的插入。靛蓝分子固定在微孔内的关键是靛蓝和配位水之间的氢键（C双键O……H-OH）。本研究强调了微孔和氢键在有机-无机杂化颜料合成中的重要作用。
Maya blue is an ancient hybrid pigment composed of indigo and microporous palygorskite, with a fantastic hue and outstanding stability. Its color-causing and stabilization mechanism are unsolved problems. In this work, different palygorskite materials were obtained by heating at 180, 300 and 570 °C, with raw palygorskite as a reference. Maya blue-like pigments were prepared from these palygorskite materials and solid indigo. The microporous structure of palygorskite and the status of inside water molecules were investigated by thermal analysis, X-ray diffraction, Fourier transform infrared and microporous analysis. The color properties, chemical resistance and photostability of pigments were characterized by reflectance spectra, CIE color parameters and color differences after the attack of concentrated nitric acid, dimethyl sulfoxide, and visible light exposure equaling to about 100 years. It was confirmed that the greenish-blue and stable hybrid pigment could only be prepared when indigo molecules were inserted into the micropores of palygorskite. Zeolitic water molecules inside the micropores should be removed because they hindered the insertion of indigo molecules. The key to immobilizing indigo molecules inside micropores was hydrogen bonds between indigo and coordinated water (Cdouble bondO … …H–OH). This study emphasized the important role of micropores and hydrogen bonds in the synthesis of organic-inorganic hybrid pigments.