LAUSR

Nacre's biomineralization process and its self-organizing brick-and-mortar crystalline microstructure have inspired many researchers to develop new materials derived from the natural world. In our study, we took a novel approach to two-dimensional (2-D) crystallization. That is, we applied the biomineralization self-organizational principle that exists in natural materials to a biopolymer (polylactide). The CO2-induced crystallization of poly(d-lactide), with its unique diffusion-controlled crystallization mechanism, tends to produce distinct 2-D spherulitic structures. We found that these 2-D spherulites were self-organizing in nature, and that they created a stack of 2-D spherulitic structures. These crystalline microstructures, with their intervening amorphous phase, were foamed in situ due to the CO2-induced crystallization self-exclusion phenomenon. We compared the resultant crystalline structure with nacre's brick-and-mortar crystalline microstructure to confirm the biomimetic principle of self-organization. To the best of our knowledge, this is the first time that a biopolymer has been crystallized in a 2-D manner in a way that resembles nature's biomineralization process. The hierarchical crystalline microstructure is morphologically similar to that of nacre biomaterials. This novel crystallization technique is simple, absolutely non-toxic and works swiftly to produce a brick-and-mortar crystalline microstructure with a high degree of order. © 2017 Society of Chemical Industry