For the first time, researchers have successfully grown artificial mother-of-pearl, the iridescent, multilayered material that lines the shells of mollusks such as abalone Haliotis tuberculata (above left). Several teams have tried—and failed—to create the material in the lab, and researchers have previously only been able to produce it by recrystallizing mother-of-pearl, also known as nacre, that had been extracted from shells. The previous attempts to make artificial nacre failed largely because the alternating layers of material didn't hold together—sort of like plywood with bad glue. In the latest research, the scientists solved this delamination problem by alternatively dipping a sheet of material into solutions of a vinyl polymer and an acrylic acid. They then dissolved the dried acid and hardened the remaining polymers by exposing them to ultraviolet light. Finally, the team slathered the porous surface with a noncrystalline form of calcium carbonate, which infiltrated the material and then slowly crystallized when placed in a container of humid air. By repeating this sequence of steps, the researchers created a multilayered coating (on strip at right above) that is tougher and even more iridescent than natural mother-of-pearl. The new fabrication technique, which is performed at room temperature using simple chemistry and inexpensive materials, may have wide applications, such as providing a way to create strong natural composite coatings for delicate surfaces such as plastics, say the researchers, who report their results today in Nature Communications.
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