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Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by π-π Stacking Interactions
Published on: October 10, 2016
Apollonian packing in polydisperse emulsions.
Sylvie Kwok1, Robert Botet, Lewis Sharpnack
1Laboratoire Colloïdes et Matériaux Divisés - Chemistry, Biology and Innovation (CBI) UMR8231, ESPCI Paris, CNRS, PSL*Research University, 10 rue Vauquelin, 75005 Paris, France. sylvie.kwok@espci.fr.
Researchers discovered polydisperse high internal-phase-ratio emulsions (HIPEs) where 95% oil droplets spontaneously organize into Apollonian packing structures. This unique droplet evolution differs from typical emulsion coalescence mechanisms.
Area of Science:
- Colloid and Surface Science
- Materials Science
- Physics
Background:
- High internal-phase-ratio emulsions (HIPEs) are typically characterized by a high volume fraction of dispersed droplets.
- Understanding droplet organization and evolution in concentrated emulsions is crucial for materials design.
Purpose of the Study:
- To investigate the spontaneous organization and evolution of droplet size distributions in polydisperse HIPEs.
- To determine the packing structure of droplets in aged HIPEs and compare it with theoretical models.
Main Methods:
- Formation of polydisperse HIPEs by emulsifying oil in a surfactant-poor aqueous phase.
- Monitoring droplet size distribution evolution post-stirring.
- Analysis of droplet packing structure using Small-angle X-ray Scattering (SAXS).
Main Results:
- Discovery of polydisperse HIPEs with 95% internal-phase volume fraction where droplets remain spherical.
- Observed spontaneous evolution of droplet size distributions towards power laws with an Apollonian exponent.
- SAXS data confirmed droplet packing structure aligns with random Apollonian packing.
Conclusions:
- The formation and evolution of these concentrated HIPEs follow unique mechanisms governed by volume and sphericity conservation.
- Droplet organization in aged HIPEs adheres to Apollonian packing rules, differing from dilute emulsion coalescence.
- This discovery offers new insights into the self-assembly and structural properties of highly concentrated emulsions.
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