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Exploiting Confinement to Study the Crystallization Pathway of Calcium Sulfate
Author(s) -
AnduixCanto Clara,
Levenstein Mark A.,
Kim YiYeoun,
Godinho Jose R. A.,
Kulak Alexander N.,
Niño Carlos González,
Withers Philip J.,
Wright Jonathan P.,
Kapur Nikil,
Christenson Hugo K.,
Meldrum Fiona C.
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202107312
Subject(s) - crystallization , nanoporous , precipitation , gypsum , materials science , synchrotron , phase (matter) , amorphous solid , crystal growth , chemical physics , chemical engineering , amorphous calcium phosphate , nanotechnology , crystallography , calcium , chemistry , optics , physics , organic chemistry , meteorology , engineering , metallurgy
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 (CaSO 4 0.5H 2 O) forms via an amorphous precursor phase and that it exhibits long‐term stability in these nanoscale pores. Further, the thermodynamically stable phase gypsum (CaSO 4 2H 2 O) 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.