Colloids are systems of small particles dispersed in solvent. At high volume fractions, colloidal systems exhibit dynamics similar to those seen in molecular glasses. In the presence of polymer that can induce attractions between the colloidal particles, less dense solutions of such particles form depletion gels. The size of the colloidal particles typically used allows imaging with optical microscopy: thus, imaging these systems allows for direct detailed study of glass and gel transitions.
We are working to develop a novel colloidal system based on polyelectrolyte microcapsules (PMMs), usually investigated for their potential as drug delivery carriers. PMMs are synthesized via a layer-by-layer (LbL) technique in which oppositely charged macromolecules are alternately adsorbed on colloidal templates that are decomposed once the desired number of layers of macromolecules is adsorbed. Such microcapsules have significant tunability in size, thickness, permeability, and charge density, and they can be density and index matched in a background solvent composed mostly of water. These properties make them particularly useful for colloidal gel and glass studies.
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| Schematic diagram of microcapsule preparation. |
Experiments now underway focus on moderate volume fraction gels
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| Depletion gel of PSS/PAH PMMs and dextran. |
Would you like to learn more? If so, contact Shomeek Mukhophadyay.
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