Dye Chemistry - Exploring Colour From Nature to Lab

Book excerpt: Color, which contributes so much to the beauty of nature, is vital to the attraction and acceptability of most products used by modern society. As early as the 25th century BC, people used a limited range of natural colorants from both animal (e.g., cochineal) and vegetable (e.g., indigo, curcumin, alizarin, Tyrian purple) sources to color their surroundings and clothing. Dyes are substances that, once applied to a substrate, selectively reflect or transmit incident daylight. Most natural dyes are found in the roots, barks, leaves, bracts, flowers, skins, and shells of plants. They are classified as either organometallic or organic compounds, typically exhibiting low solubility in organic solvents. As a result, they generally remain in the solid state during processing and when applied to substrates. This book provides a comprehensive overview of the chemistry and physics of dyes and their intermediates. Chapters address such topics as chemical constituents, spectroscopic aspects, surface, solution, crystal formation, photochemistry, and their ecological and biological properties. This volume will appeal to a wide range of researchers and graduate students worldwide whose work involves dye synthesis, imaging, sensors, energy, medicine, polymers, food products, toxicological properties, and more.