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Exploiting confinement to study the crystallization pathway of calcium sulfate

DOI: 10.1002/adfm.202107312 DOI Help

Authors: Clara Anduix-Canto (University of Leeds) , Mark A. Levenstein (University of Leeds) , Yi-Yeoun Kim (University of Leeds) , Jose R. A. Godinho (University of Manchester) , Alexander N. Kulak (University of Leeds) , Carlos Gonzalez Nino (University of Leeds) , Philip J. Withers (University of Manchester) , Jonathan P. Wright (European Synchrotron Radiation Facility) , Nikil Kapur (University of Leeds) , Hugo K. Christenson (University of Leeds) , Fiona C. Meldrum (University of Leeds)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Advanced Functional Materials

State: Published (Approved)
Published: September 2021
Diamond Proposal Number(s): 13578 , 17314

Open Access Open Access

Abstract: Characterizing the pathways by which crystals form remains a significant challenge, particularly when multiple pathways operate simultaneously. Here, an imaging-based strategy is introduced that exploits confinement effects to track the evolution of a population of crystals in 3D and to characterize crystallization pathways. Focusing on calcium sulfate formation in aqueous solution at room temperature, precipitation is carried out within nanoporous media, which ensures that the crystals are fixed in position and develop slowly. The evolution of their size, shape, and polymorph can then be tracked in situ using synchrotron X-ray computed tomography and diffraction computed tomography without isolating and potentially altering the crystals. The study shows that bassanite (CaSO4 0.5H2O) forms via an amorphous precursor phase and that it exhibits long-term stability in these nanoscale pores. Further, the thermodynamically stable phase gypsum (CaSO4 2H2O) can precipitate by different pathways according to the local physical environment. Insight into crystallization in nanoconfinement is also gained, and the crystals are seen to grow throughout the nanoporous network without causing structural damage. This work therefore offers a novel strategy for studying crystallization pathways and demonstrates the significant impact of confinement on calcium sulfate precipitation, which is relevant to its formation in many real-world environments.

Journal Keywords: amorphous calcium sulfate; bassanite; confinement; crystallization; gypsum; X-ray tomography

Subject Areas: Materials, Chemistry

Instruments: I13-2-Diamond Manchester Imaging

Other Facilities: ID11 at ESRF

Added On: 18/09/2021 17:32


Discipline Tags:

Chemistry Materials Science

Technical Tags:

Imaging Tomography