Viscous sintering phenomena in liquid-liquid dispersions.

Area of Science:

• Materials Science
• Rheology
• Colloid Science

Background:

• Emulsions are mixtures of immiscible liquids.
• Viscous sintering describes the process of particle rearrangement and pore closure driven by surface tension in viscous materials.
• Understanding gel formation and contraction is crucial for material processing.

Purpose of the Study:

• To investigate viscous sintering phenomena in gels formed from highly viscous emulsion droplets.
• To analyze the contraction behavior and densification of these gels.
• To compare experimental results with existing viscous sintering models.

Main Methods:

• Formation of a gel from a highly viscous emulsion using a rupturing agent.
• Experimental observation of gel contraction and densification.
• Analysis of contraction rate and its dependence on viscosity.
• Comparison with the "cylindrical model" for viscous sintering.

Main Results:

• The gel contracts while preserving the container's geometry.
• Initial densification (up to 60%) closely follows the cylindrical model for viscous sintering.
• Deviations from the model are observed in the final stages of densification.
• An inverse relationship between contraction rate and viscosity was experimentally confirmed.

Conclusions:

• Experimental evidence supports viscous sintering as the mechanism for gel contraction.
• The cylindrical model accurately describes early-stage viscous sintering in this system.
• Deviations at later stages suggest complex phenomena or limitations of the model.
• The findings are consistent with viscous sintering theory, particularly the inverse dependence of contraction rate on viscosity.