Simulating micrometre-scale crystal growth from solution.

Area of Science:

• Materials Science
• Chemical Engineering
• Crystallography

Background:

• Crystal shape significantly impacts chemical and physical properties, crucial for industrial separation and purification.
• While thermodynamic morphology is predictable, kinetic factors govern most particle shapes during atomic assembly.
• Understanding crystal growth kinetics is vital for controlling crystallization processes.

Purpose of the Study:

• To simulate and understand the kinetic processes governing urea crystal growth at the microscale.
• To develop a model that accurately reproduces experimentally observed crystal growth without prior assumptions on surface behavior.
• To investigate the influence of solvent, supersaturation, and defects on crystal morphology.

Main Methods:

• Kinetic Monte Carlo simulations were employed to model the three-dimensional growth of urea crystals.
• The study focused on the urea-solvent interface at the nanometer scale.
• In situ atomic force microscopy was used to bridge nanoscale observations with macroscopic growth.

Main Results:

• Simulations accurately reproduced experimentally observed urea crystal growth patterns.
• The model successfully predicted microscale crystal growth without assuming independent surface growth or a priori defect concentrations.
• Insights were gained into the roles of solvent, supersaturation, and screw dislocations in crystal assembly.

Conclusions:

• The kinetic Monte Carlo approach offers a robust method for studying crystal growth, linking nanoscale phenomena to macroscopic behavior.
• This technique provides a deeper understanding of factors influencing crystal morphology.
• The methodology holds potential for the computer-aided design of crystals, especially with the inclusion of additives.