Abstract

Life occurs in three dimensional turbid aqueous systems. A cell consists for ~60 % of water and contains many organels and interfaces. The average distance between two molecules, or a molecule and a membrane interfaces is approximately 1 nm. Water and the interfaces it interacts with are of paramount importance for biological processes. The molecular, structural, dynamic, and biological properties of water, aqueous systems and aqueous interfaces are essential in understanding the complexity of life, and our ability to harness its features for novel (nano)technologies. Currently, our understanding of such soft wet and turbid biological systems is mostly derived from macro- or microscopic theories. Molecular level understanding is often absent. In this presentation I will introduce nonlinear optical methods that can be used to gain label-free molecular level information about liquid aqueous systems and nanoscopic interfaces in turbid media. We have used nonlinear light scattering methods to understand the origin of the intrinsic charge on nanoscopic hydrophobic / water interfaces. I will also discuss the molecular level stabilization mechanism of nanodroplets, which differs significantly from the apparent mechanism for stabilizing macroscopic interfaces.