Biomimetic type morphologies of calcium carbonate grown in absence of additives

Andreassen, Jens‐Petter; Beck, Ralf; Nergaard, Margrethe

doi:10.1039/c2fd20056b

Cited by 39 publications

(38 citation statements)

References 54 publications

(65 reference statements)

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“…In synthetic vaterite, the morphology of crystals depends on the growth conditions evolving from hexagonal monocrystalline plates, to florets and finally to spherulites as the super-saturation increases 84 . Adding alcohol also changes the morphology of synthetic vaterite crystals 44 .…”

Section: Discussionmentioning

confidence: 99%

Narrowly Distributed Crystal Orientation in Biomineral Vaterite

et al. 2015

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Biominerals formed by animals provide skeletal support, and many other functions. They were previously shown to grow by aggregation of amorphous nanoparticles, but never to grow ion-by-ion from solution, which is a common growth mechanism for abiotic crystals. We analyze vaterite (CaCO3) multi-crystalline spicules from the solitary tunicate Herdmania momus, with Polarization-dependent Imaging Contrast (PIC)-mapping, scanning and aberration-corrected transmission electron microscopies. The first fully-quantitative PIC-mapping data, presented here, measured 0°-30° angle spreads between immediately adjacent crystals. Such narrowly distributed crystal orientations demonstrate that crystallinity does not propagate from one crystal to another (0° angle spreads), nor that new crystals with random orientation (90°) nucleate. There are no organic layers at the interface between crystals, hence a new, unknown growth mechanism must be invoked, with crystal nucleation constrained within 30°. Two observations are consistent with crystal growth from solution: vaterite microcrystals express crystal faces, and are smooth at the nanoscale after cryo-fracture. The observation of 30° angle spreads, lack of interfacial organic layers, and smooth fracture figures broadens the range of known biomineralization mechanisms and may inspire novel synthetic crystal growth strategies. Spherulitic growth from solution is one possible mechanism consistent with all these observations.

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Section: Discussionmentioning

confidence: 99%

Narrowly Distributed Crystal Orientation in Biomineral Vaterite

et al. 2015

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“…Other methods, such as solution mixture 8,79 and hydrothermal synthesis, 88 can also produce spherulitic aragonite with different additives and thermal treatments. Aragonite spherulites synthesized from different methods, however, can have different morphologies.…”

Section: Methodsmentioning

confidence: 99%

Spherulitic Growth of Coral Skeletons and Synthetic Aragonite: Nature’s Three-Dimensional Printing

Sun¹,

Marcus

Frazier³

et al. 2017

ACS Nano

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Coral skeletons were long assumed to have a spherulitic structure, that is, a radial distribution of acicular aragonite (CaCO 3 ) crystals with their c-axes radiating from series of points, termed centers of calcification (CoCs). This assumption was based on morphology alone, not on crystallography. Here we measure the orientation of crystals and nanocrystals and confirm that corals grow their skeletons in bundles of aragonite crystals, with their caxes and long axes oriented radially and at an angle from the CoCs, thus precisely as expected for feather-like or "plumose" spherulites. Furthermore, we find that in both synthetic and coral aragonite spherulites at the nanoscale adjacent crystals have similar but not identical orientations, thus demonstrating by direct observation that even at nanoscale the mechanism of spherulite formation is non-crystallographic branching (NCB), as predicted by theory. Finally, synthetic aragonite spherulites and coral skeletons have similar angle spreads, and angular distances of adjacent crystals, further confirming that coral skeletons are spherulites. This is important because aragonite grows anisotropically, 10 times faster along the c-axis than along the a-axis direction, and spherulites fill space with crystals growing almost exclusively along the c-axis, thus they can fill space faster than any other aragonite growth geometry, and create isotropic materials from anisotropic crystals. Greater space filling rate and isotropic mechanical behavior are key to the skeleton's supporting function and therefore to its evolutionary success. In this sense, spherulitic growth is Nature's 3D printing. KEYWORDS: Ion attachment, crystallization by particle attachment, CPA, biomineralization, PEEM, PIC-mapping, mesocrystal S pherulites are polycrystalline structures in which acicular crystals radiate from a common center and grow approximately synchronously so the final shape of a spherulite resembles a sphere. 1−7 Figure 1 shows two types of spherulites: "spherical spherulite", in which the crystal fibers start from a point, or "plumose spherulite", in which crystal fibers radiate at an angle from the line. 7 Spherulites start forming as an aggregate of parallel acicular crystals termed "fibers", then form a "sheaf of wheat" structure, and with the growth of more fibers eventually become complete spheres. 8 In an ideal spherulite, fibers radiate from the center and contain all possible orientations within the sphere. Since the fast-growing axis in aragonite (CaCO 3 ) is the c-axis, 9 in spherulites each fiber elongation direction coincides with the crystalline c-axis. 10,11 In real spherulites, biogenic 12 and synthetic, 7 the crystal orientations are not perfectly radial nor continuously varying with angle, they deviate slightly from radial and exhibit small but abrupt changes in orientation, termed "branching". In Figure 1 branching angles are smaller than 30°in direction and in crystal lattice orientation. This is distinct from crystallographic branching, which occurs in sno...

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“…5 shows the formation and growth of a single ACC particle. The amorphous particle grew to a few microns in diameter, before briefly shrinking in size prior to nucleation of two particles at or just below the surface of the ACC precursor, both of which exhibited the typical sheathof-wheat morphology of aragonite [66]. The aragonite grew rapidly, consuming the amorphous precursor, with physical contact maintained between the two phases throughout the transformation process.…”

Section: Nucleation Via Multiple Direct and Indirect Pathwaysmentioning

confidence: 98%

In-situ liquid phase TEM observations of nucleation and growth processes

Yoreo

2016

Progress in Crystal Growth and Characterization of Materials

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Nucleation and growth of crystals is a pervasive phenomenon in the synthesis of man-made materials, as well as mineral formation within geochemical and biological environments. Over the past two decades, numerous ex situ studies of crystallization have concluded that nucleation and growth pathways are more complex than envisioned within classical models. The recent development of in situ liquid phase TEM (LP-TEM) has led to new insights into such pathways by enabling direct, real-time observations of nucleation and growth events. Here we report results from LP-TEM studies of Au nanoparticle, CaCO3 and iron oxide formation. We show how these in situ data can be used to obtain direct evidence for the mechanisms underlying crystallization, as well as dynamic information that provides constraints on important kinetic and thermodynamic parameters not available through ex situ methods.

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Biomimetic type morphologies of calcium carbonate grown in absence of additives

Cited by 39 publications

References 54 publications

Narrowly Distributed Crystal Orientation in Biomineral Vaterite

Narrowly Distributed Crystal Orientation in Biomineral Vaterite

Spherulitic Growth of Coral Skeletons and Synthetic Aragonite: Nature’s Three-Dimensional Printing

In-situ liquid phase TEM observations of nucleation and growth processes

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