Microgels: special or strange?

Speaker

Walter Richtering, Institute of Physical Chemistry, RWTH Aachen University, European Union

Abstract

Microgels are macromolecular networks swollen by the solvent they are dissolved in. They are unique systems that are distinctly different from common colloids, such as, e.g., rigid nanoparticles, flexible macromolecules, micelles or vesicles. When swollen, they are soft and have a fuzzy surface with dangling chains and the presence of cross-links provides structural integrity - in contrast to linear and (hyper-) branched polymers. Finally, micro-gels reveal interface activity without being amphiphilic.

The combination of being soft and porous while still having a stable structure provides different routes to tune the microgels' properties. Introducing chemical functionality at different positions or changing the morphology will make the microgels behaving as hard or soft objects. Obviously, the degree of crosslinking is important.

We will discuss the interaction of microgels of different chemical functionality and architecture as, e.g., core-shell, hollow and multi-shell hollow microgels in bulk solution as well as at fluid interfaces.

The structure is probed by means of neutron scattering employing contrast variations as well as by (super-resolved) fluorescence microscopy. Properties of microgels at interfaces are determined by means of scanning force and electron microscopy as well as by compression isotherms. The experimental results will be compared to computer simulations.