Weatherability and heat resistance enhanced by interaction between AG25 and Mg/Al-LDH

Although inorganic pigments in common spectral tuning materials show good weatherability and heat resistance, the limited color choices, weak coloring power, poor dispersibility, and a possibility of toxicity limit their development. On the basis of organic pigments which possess a wide range of colors, high coloring power, good transparency, and high safety, herein, the modified pigment and biomimetic coating with improved weatherability, especially ultraviolet (UV) resistance (from 2 to 6 days), was achieved by intercalating acid green 25 (AG25) pigment into Mg/Al-layered double hydroxides (Mg/Al-LDH). Furthermore, the heat resistance of AG25 was also significantly increased. Moreover, the spectral stability of pigments after heat treatment is superior with almost unchanged spectral profile and green reflection peak. The formation of strong N–H bonds and the S–M (Mg, Al) bonds between Mg/Al-LDH laminates and AG25 molecules contributes to the improvement. This work shows potential for biomimetic leaf materials in respect of reflective spectra stability. Graphical Abstract