Coherence Seminar: 3-Dimensional Imaging of CaCO3 vaterite particles during their transformation to calcite by coherent X-ray diffraction imaging

QUICK INFORMATION
Type
Seminar
Start Date
27-10-2017 11:00
End Date
27-10-2017 13:00
Location
Room 1-10, Common Building
Speaker's name
Oxana Cherkas
Speaker's institute
Institut des Molécules et des Matériaux du Mans (IMMM) - Univ. Le Mans (France)
Contact name
Ewa Wyszynska
Host name
Oier Bikondoa
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3 Dimensional Imaging of CaCO3 vaterite particles during their transformation to calcite by coherent X-ray diffraction imaging

O. Cherkas1, T. Beuvier2, D.W. Breiby3, F. Zontone2, Y. Chuskin2 and A. Gibaud1

1- LUNAM, IMMM, UMR 6283 CNRS, Faculté des Sciences 72085 Le MANS Cedex 09, France

2- ESRF, bEuropean Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble, France

3- Department of Physics, Norwegian University of Science and Technology (NTNU), Høgskoleringen 5, Trondheim, 7491, Norway

Correspondance email: alain.gibaud@univ-lemans.fr

Calcium carbonate has three allotropic forms: calcite, aragonite and vaterite. Vaterite precipitates as highly porous spheroïdal particles which makes them interesting for encapsulation and drug delivery applications [1,2]. Yet vaterite is metastable as it can be easily transformed into calcite and/or aragonite by different ways: in aqueous media and at high temperature. We have utilized three dimensional coherent diffraction imaging (3D-CXDI) to analyze the phase transformation of vaterite micro-particles into calcite occurring by both immersion in water and thermal annealing above 400°C. This technique provides 3D tomograms with a resolution down to 30nm. This opens new perspectives in material engineering to unveil the inner structure of materials as small as a few micrometers in diameter [3,4].

In this presentation, I will show that the evolution of the internal and outer morphology of calcium carbonate particles during the allotropic phase transformation can be analyzed by CXDI. In water, we show that vaterite transforms into calcite that has the rhombohedral structure (Fig.1a). On the contrary, when vaterite is annealed, the particles transform into calcite without any modification of the initial spherical shape, but with significant changes in their surface roughness and porosity (Fig.1c). In the case of annealed particles we utilize CXDI to extract quantitative information about the mass, volume and porosity of particles. This type of analysis allows us to obtain a 3D-representation of the unconnected and connected pores.

Fig 1. CDXI and SEM images of (a) particles immersed in tap water during 3h, (b) pristine particles and (c) annealed particles.  Scale bar – 1µm.

References

[1] Hassani LN and al. Journal of Materials Chemistry B, 1, 4011-4019 (2013).

[2] Volodkin DV, Larionova NI, Sukhorukov GB Biomacromolecules, 5, 1962-1972 (2004).

[3] Miao JW, Sandberg RL, Song CY, Journal of Selected Topics in Quantum Electronics, 18, 399-410 (2012).

[4] Sandberg RL and al. Journal of the Minerals, Metals and Materials Society, 65, 1208-   1220 (2013)

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