Fish gelatin/Laponite biohybrid elastic coacervates: a complexation kinetics-structure relationship study

Area of Science:

• Materials Science
• Colloid Science
• Polymer Science

Background:

• Complex coacervation is a liquid-liquid phase separation process crucial for forming functional materials.
• Laponite nanoplatelets and fish gelatin offer unique properties for coacervate formation.

Purpose of the Study:

• To investigate the influence of pH, ionic strength, and composition on complex coacervation kinetics and properties.
• To characterize the structure and viscoelasticity of fish gelatin-Laponite coacervates.
• To establish relationships between phase separation kinetics and coacervate network structure.

Main Methods:

• Turbidity measurements to determine optimal coacervation conditions.
• Thermogravimetric analysis for heat-resistance assessment.
• Oscillatory shear rheology to characterize coacervate structure and viscoelastic properties.

Main Results:

• Optimal conditions for coacervation were identified.
• Gelatin/nanoclay coacervates exhibited excellent heat resistance.
• Coacervate structure followed power-law behavior with a characteristic length scale of ~8.25 nm under optimal conditions.
• A new kinetics parameter K was inversely proportional to the rheological length scale, linking phase separation kinetics to network compactness.

Conclusions:

• The study successfully optimized complex coacervation of Laponite and fish gelatin.
• The resulting coacervates are heat-resistant, dense, and structured.
• Phase separation kinetics directly influence the equilibrium structure and compactness of the coacervate networks.