Berlin 2012 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 28: Colloids and Complex Liquids I

CPP 28.7: Talk

Wednesday, March 28, 2012, 17:00–17:15, C 130

(contribution withdrawn) Smart Microgel Capsules and Model Colloids Tailored by Droplet-Based Microfluidics — •Sebastian Seiffert — Helmholtz Zentrum Berlin, F-I2 Soft Matter and Functional Materials, Hahn-Meitner-Platz 1, 14109 Berlin, Germany

Micrometer-sized polymer gel particles can be produced with exquisite control by droplet-based microfluidics. The idea of this approach is to use emulsion droplets as templates to control the particle size, shape, and monodispersity. To extend this control towards controlling the material properties of the microgels, microfluidic templating can be combined with the use of functional, macromolecular precursors; this separates the polymer synthesis from the particle gelation and allows each to be controlled independently. It also allows complex morphologies such as hollow, anisotropic, or multi-layered microgels to be formed and complexed with additives such as drugs, colloids, or living cells. In addition to their utility for encapsulation, these microgels can serve as model systems to explore how the particle stiffness and size affect the bulk and shear elasticity of compressed particulate suspensions. While it is known that in dilute solution, the dynamics of colloidal microgels strongly dependends on the particle size, it is unclear to what extent the dynamics of microgel systems is determined by the particle size if the system is densely packed. A droplet-based microfluidic approach allows such dense-packed microgel systems to be prepared with particles of strongly varying size, revealing that the isotropic compressibility and shear elasticity of both colloidal-scale and granular-scale systems show universal, macrogel-type scaling independent of the particle size.