Kinetic Retraction at the Onset of Concomitant Crystallization and Implication on Polymorphic Formation

Area of Science:

• Crystallization Science
• Materials Science
• Chemical Engineering

Background:

• Polymorphism, the ability of a solid material to exist in multiple crystalline forms, significantly impacts material properties.
• Understanding and controlling polymorphic outcomes is crucial in various scientific and industrial applications.
• The characterization of polymorphic formation in dipolymorphic systems presents unique challenges.

Purpose of the Study:

• To introduce and evaluate the four-quadrant regimes of attainable polymorph crystallization (FQR-APC) plot for characterizing polymorphic formation.
• To compare the efficacy of the FQR-APC plot with the Ostwald ratio (OR) concept in describing polymorphic outcomes.
• To identify key indicators of concomitant polymorphism during crystallization.

Main Methods:

• Numerical simulations of crystallization kinetics for a dipolymorphic system.
• Development and application of the FQR-APC plot.
• Comparative analysis with the Ostwald ratio (OR) concept.

Main Results:

• The FQR-APC plot was developed based on numerical simulations of crystallization kinetics.
• A retraction in the polymorphic composition of the most stable form was identified as a characteristic indicator of concomitant polymorphism.
• Both the FQR-APC plot and the Ostwald ratio (OR) demonstrated good agreement in describing polymorphic outcomes.

Conclusions:

• The FQR-APC plot is a valuable tool for characterizing polymorphic formation in dipolymorphic systems.
• The FQR-APC plot and Ostwald ratio (OR) provide consistent results despite their different theoretical foundations.
• The findings aid in a deeper understanding of polymorph crystallization and control.