A lustrous appearance and interference-based colors make pearlescent pigments attractive for use in applications such as automotive paints, plastics, consumer electronics, and cosmetics. A combination of interference and absorption in the visible light spectrum improves significantly the hiding power as well as the color strength of pearlescent pigments while potentially extending their color range. The aim of the present study was to introduce synthetic fluorohectorites, having an appreciable diameter (~20 μm) and aspect ratio (~1000), as promising colored cores for pearlescent pigments. Fluorohectorites can adopt a variety of colors by ion-exchange reaction with cationic organic dyes of high absorption coefficient. Unlike related dye-exchanged natural montmorillonite clays, which undergo acid activation accompanied by release of dye at low pH, as is required for subsequent coating with TiO2 in an environment with low pH and elevated temperature, no leaching was observed with dye-exchanged synthetic fluorohectorites ([Na0.5]int.[Mg2.5Li0.5]oct.[Si4]tet.O10F2). Due to its significantly greater layer charge, more organic dye molecules were adsorbed per volume of the fluorohectorite than for montmorillonite. Consequently, the free volume available in the interlayer space for H3O+ diffusion was less for synthetic fluorohectorite than for montmorillonite. Acid attack via interlayer space was, therefore, retarded significantly for fluorohectorite. Acid attack from the external edges of synthetic fluorohectorites was in the range of conventionally applied mica pigment core (fluorophlogopite, ([K]int.[Mg3]oct.[AlSi3]tet.O10(F,OH)2) because of the comparable large diameter of the platelets. Montmorillonite, however, occurs with particle diameters typically <200 nm and the much increased relative contribution of edges to the total surface area also makes them more prone to acid attack and concomitant leaching. Aside from leaching stability, the confinement of organic dyes in the interlayer space restricts rotational and vibrational motions, which in turn stabilizes the dyes typically by ~100°C against thermal decomposition as compared to chloride salts of the dyes.

中文翻译：

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珠光颜料的吸收颜料芯

有光泽的外观和基于干涉的颜色使珠光颜料在汽车油漆、塑料、消费电子产品和化妆品等应用中具有吸引力。可见光谱中的干涉和吸收相结合可显着提高珠光颜料的遮盖力和颜色强度，同时有可能扩大其颜色范围。本研究的目的是引入具有可观直径（~20 μm）和纵横比（~1000）的合成氟锂蒙脱石，作为珠光颜料的有色核心。通过与高吸收系数的阳离子有机染料发生离子交换反应，氟蒙脱石可以呈现多种颜色。与相关的染料交换天然蒙脱石粘土不同，后者在低 pH 值下经历酸活化并伴随染料释放，正如随后在低 pH 值和高温环境中用 TiO2 涂覆所需要的那样，染料交换的合成含氟锂蒙脱石（[Na0.5]int.[Mg2.5Li0.5]oct.[Si4]tet. O10F2)。由于其显着更大的层电荷，与蒙脱石相比，每体积含氟锂蒙脱石吸附的有机染料分子更多。因此，合成氟锂蒙脱石的层间空间中可用于 H3O+ 扩散的自由体积小于蒙脱石。因此，对于氟锂蒙脱石，通过层间空间的酸侵蚀显着延迟。来自合成氟锂蒙脱石外部边缘的酸侵蚀在常规应用的云母颜料核（氟金云母，([K]int.[Mg3]oct.[AlSi3]tet.O10(F,OH)2）的范围内，因为具有可比性大直径的血小板。然而，蒙脱石的粒径通常小于 200 nm，边缘对总表面积的相对贡献大大增加，也使它们更容易受到酸侵蚀和伴随浸出。除了浸出稳定性之外，有机染料在夹层空间中的限制限制了旋转和振动运动，与染料的氯化物盐相比，这反过来通常使染料稳定约 100°C 以防止热分解。