Deconstructing 3D growth rates from transmission microscopy images of facetted crystals as captured in situ within supersaturated aqueous solutions

• Published in: Journal of applied crystallography Vol. 57; no. 5; pp. 1557 - 1565
• Main Authors: Ma, Cai Y., Jiang, Chen, Ilett, Thomas P., Hazlehurst, Thomas A., Hogg, David C., Roberts, Kevin J.
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01.10.2024; Blackwell Publishing Ltd
• Subjects: 3D crystal growth evolution; Aqueous solutions; Crystal growth; crystal morphological images; Crystal morphology; Crystals; facet‐based crystal‐growth‐rate measurements; Glutamic acid; Growth rate; Image processing; Image transmission; in situ characterization; Light microscopy; Light reflection; l‐glutamic acid; Microscopy; Optical microscopy; polyhedral image analysis; Research Papers; Single crystals; Supersaturation; transmission microscopy; Visual observation; facet-based crystal-growth-rate measurements; transmission microscopy; l-glutamic acid; 3D crystal growth evolution; crystal morphological images; in situ characterization; polyhedral image analysis; supersaturation
• ISSN: 1600-5767; 0021-8898; 1600-5767
• DOI: 10.1107/S1600576724008173

Here, a morphologically based approach is used for the in situ characterization of 3D growth rates of facetted crystals from the solution phase. Crystal images of single crystals of the β‐form of l‐glutamic acid are captured in situ during their growth at a relative supersaturation of 1.05 using transmission optical microscopy. The crystal growth rates estimated for both the {101} capping and {021} prismatic faces through image processing are consistent with those determined using reflection light mode [Jiang, Ma, Hazlehurst, Ilett, Jackson, Hogg & Roberts (2024). Cryst. Growth Des.24, 3277–3288]. The growth rate in the {010} face is, for the first time, estimated from the shadow widths of the {021} prismatic faces and found to be typically about half that of the {021} prismatic faces. Analysis of the 3D shape during growth reveals that the initial needle‐like crystal morphology develops during the growth process to become more tabular, associated with the Zingg factor evolving from 2.9 to 1.7 (>1). The change in relative solution supersaturation during the growth process is estimated from calculations of the crystal volume, offering an alternative approach to determine this dynamically from visual observations. The crystal growth rate of the basal plane {010} face of β‐form l‐glutamic acid is estimated from the shadow widths of the prismatic {021} faces in optical microscopy images. This new approach for the in situ characterization of 3D crystal shape and size is part of wider research into digital crystallization process engineering, encompassing machine learning, morphological population balance modelling and crystallizer hydrodynamics simulation.