Mass transfer limitations at crystallizing interfaces in an atomic force microscopy fluid cell: a finite element...

Area of Science:

• Materials Science
• Chemical Engineering
• Physical Chemistry

Background:

• Atomic force microscopy (AFM) is crucial for in situ crystal growth studies.
• Mass transfer limitations in AFM fluid cells are not well understood.
• Accurate measurements require understanding solute transport dynamics.

Purpose of the Study:

• To analyze fluid flow and mass transfer in an AFM fluid cell during crystal growth.
• To quantify the impact of mass transfer limitations on solute concentration.
• To validate a computational model with experimental data.

Main Methods:

• Continuum analysis of flow and mass transfer.
• Three-dimensional finite element method simulations.
• Comparison with calcium oxalate monohydrate (COM) crystal growth experiments.

Main Results:

• Nonlinear momentum transport alters flow fields near the AFM tip.
• Solute concentration is reduced between the tip and crystal due to growth and mass transfer resistance.
• For COM, solute concentration was 3.1% lower than inlet values.
• Increased flow rate had minimal impact on concentration differences due to tip shielding.

Conclusions:

• Mass transfer limitations significantly affect solute concentration in AFM fluid cells.
• Computational models can improve the interpretation of AFM crystal growth data.
• Understanding these limitations is key for precise in situ measurements.