Biomorphs are inorganic assemblies of crystalline nanorods that form non-crystalline microshapes such as helices, funnels, and leaf-shaped sheets. This nano-to-microscale self-organization occurs from simple reactants in aqueous solution and suggests new engineering methods as well as insights into biomineralization. However, the underlying mechanisms controlling long range nanorod order into the production of biologically inspired morphologies are not understood. Here we describe a reaction-diffusion model for sheet growth that reproduces the experimentally observed biomorph shapes. The sheet edges display self-similar logarithmic sprials inducing the final cardiod, leaf-like shape. An expanded model includes a nematic-like director field that sets the average nanorod orientation irreversibly during crystallization. The growth front of worm-like biomorph helices also obeys logarithmic spirals suggesting future applications of reaction-diffusion models for the simulation of three-dimensional biomorphs.

Reaction-diffusion model to describe the self organization of polycrystalline nanorods

255th National Meeting (2018)

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