Controlling the crystal structure of succinic acid via microfluidic spray-drying

Area of Science:

• Materials Science
• Physical Chemistry
• Chemical Engineering

Background:

• Material properties are dictated by their structure.
• Controlling the structure of low molecular weight organic compounds is difficult due to their high crystallization tendency from solution.
• Rapid drying techniques can limit molecular arrangement time, enabling structure control.

Purpose of the Study:

• To investigate the control of crystal structure in low molecular weight organic compounds using rapid drying.
• To determine the influence of supersaturation rate on the resulting crystal structure and stability.
• To explore the application of surface acoustic wave (SAW) spray-drying for material structure engineering.

Main Methods:

• Utilizing a surface acoustic wave (SAW) based spray-drier to generate airborne drops of succinic acid solutions.
• Formulating succinic acid at varying initial concentrations to achieve different supersaturation rates.
• Analyzing the crystal structure and stability of the resulting succinic acid particles over time.

Main Results:

• Succinic acid's crystal structure can be effectively controlled by manipulating the supersaturation rate during spray-drying.
• Metastable crystal structures of succinic acid are preserved for over 3 months when initial concentrations are below 2% of saturation.
• Higher supersaturation rates, achieved with lower initial solute concentrations, enhance the stability of metastable phases.

Conclusions:

• Surface acoustic wave (SAW) spray-drying offers a viable method for controlling the crystal structure of low molecular weight organic compounds.
• The supersaturation rate is a critical parameter for dictating both the initial crystal form and its long-term stability.
• This approach provides new avenues for tailoring material properties by controlling their crystalline structure.