Effect of liquid pool concentration on chemically reactive drop impact gelation process

Area of Science:

• Fluid Dynamics
• Materials Science
• Chemical Engineering

Background:

• Gelation involves coupled hydrodynamics and chemical reactions.
• Understanding these coupled effects is crucial for controlling gel properties.
• Previous studies often simplify the complex interplay of forces during gel formation.

Purpose of the Study:

• To investigate the coupled effects of hydrodynamics and chemical reaction during the gelation of sodium alginate.
• To analyze the dynamics of crater formation and gel growth.
• To determine gelation energy and identify key energy contributions to crater growth.

Main Methods:

• High-speed imaging and image processing to capture and analyze crater dynamics.
• Experimental variation of drop impingement height and calcium chloride concentration.
• Development and validation of a mathematical model for crater growth kinetics.
• Scanning electron microscopy (SEM) for surface morphology analysis.

Main Results:

• Crater formation and rapid phase transition from liquid to gel observed upon impact.
• Gelation energy determined by validating experimental data with a mathematical model.
• Gel swelling observed beyond a critical calcium chloride concentration.
• SEM analysis revealed effects of gelation on alginate gel homogeneity and strength.

Conclusions:

• The study elucidates new insights into the gelation process from a fluid dynamics perspective.
• Hydrodynamic forces significantly influence gel formation and material properties.
• Controlling impingement height and reactant concentration allows for tailored gel characteristics.