The term soft matter refers to a large class of condensed matter systems that simultaneously exhibit attributes of solids and liquids. Many of these systems show complex features like ordering, structuring, and/or self-assembly effects and as the underlying interactions are typically on the order of the thermal energy (at room temperature) soft matter systems exhibit notable, thermally driven fluctuations and are highly responsive to thermal or mechanical stresses. 

This course covers the structure, properties and interactions found in soft matter systems, such as colloids, polymers and surfactants. It provides information about the fluid aspects of the systems, such as their mobility or elasticity. The content will be discussed based on theoretical models as well as common experimental techniques, which will be introduced in detail. Analogues to biological systems will be drawn where appropriate. The following topics will be covered:

• Intermolecular forces
• Elementary properties of colloids, (bio)polymers, surfactants/lipids, (cell) membranes, active matter (e.g., bacteria)
• Theory and measurement of random motion (diffusion): Einstein-Smoluchowski, Langevin; single particle tracking (SPT), dynamic light scattering (DLS), fluorescence correlation spectroscopy (FCS), fluorescence recovery after photobleaching (FRAP)
• Random motion in 2D Fluids: Stokes' paradox and solutions thereof
• Theory and measurement of surface interactions: Poisson-Boltzmann, Derjaguin-Landau-Verwey-Overbeek; direct force measurements using SFA and AFM
• Measurement of polymer properties using light scattering, small angle X-ray/neutron scattering (SAXS/SANS)
• Probing (un)folding and unbinding of single (bio)polymers close to/far from the thermodynamic equilibrium: FRET, TIRF; AFM, optical/magnetic tweezers; the physics behind dynamic force spectroscopy; Jarzynski’s equality