Nonlinear Optical Spectroscopy of Soft Matter Interfaces

Molecular interfacial properties of colloidal soft matter systems (for example vesicle fusion, or particle synthesis) can be investigated without the need of planar model systems or fluorescent labelling. Exclusively observing chemical properties and changes in a molecular layer of a few molecular dimensions thick around a small particle adds a new dimension to the field of surface science (see figure).Soft matter consists of complex molecules that can undergo drastic structural transformations under mild changes of chemical and physical conditions. Since a wide variety of chemical, physical and biological processes occur at soft matter interfaces, they can exhibit complex behavior. This is even more so for interfaces of colloidal soft matter since the relative amount of interface material increases by orders of magnitude. Herein, we focus on new developments that enable us to obtain detailed molecular structural changes in the topmost molecular layers of soft matter interfaces composed of complex bio‐molecules. In particular, the possibilities to probe interfaces of colloidal soft matter systems are discussed.