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Tailoring Calcium Carbonate to Serve as Optical Functional Material: Examples from Biology and Materials Science
Author(s) -
Schmidt Ingo,
Wagermaier Wolfgang
Publication year - 2017
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.201600250
Subject(s) - calcite , calcium carbonate , biomineralization , materials science , birefringence , nanocrystalline material , amorphous solid , amorphous calcium carbonate , nanotechnology , mineralogy , chemical engineering , optics , chemistry , crystallography , composite material , physics , engineering
In nature and technology there are many examples of micron sized optical systems based on minerals. The thermodynamically most stable polymorph of calcium carbonate (CaCO 3 ) –calcite– exhibits birefringence. However, nature uses biomineralization approaches to produce CaCO 3 based optical functional materials, for example calcite mircrolens arrays as part of the photoreceptor system of brittlestars, amorphous CaCO 3 (ACC) plant cystoliths as light scatterers and calcite trilobite eyes. In this short review, we illustrate basic strategies to produce optical materials from CaCO 3 by manipulating the material structure. These strategies are driven by the aim to eliminate or reduce the birefringent properties of calcite, or even, to turn this property into an advantage. We report on the formation, structure, and functions of micron sized (hemi‐)spherical objects made from CaCO 3 with biological origin but also in bio‐inspired synthetic examples. We highlight aspects, which pave the way to learn from nature and how to characterize natural and artificial systems. In conclusion, we identify three main possibilities to make optical materials based on CaCO 3 : (i) orienting the optical axis along the desired light propagation direction, (ii) stabilizing metastable phases, and (iii) producing nanocrystalline structures, which reduce birefringent properties.