In-situ spectroscopic ellipsometry for studies of thin films and membranes

The properties of a thin polymer film can be significantly affected by the presence of a penetrant. It is also known that the behavior of ultra-thin polymer films (<100 nm) may deviate from the bulk behavior. This sole impact of film thickness reduction is often referred to as a nano-confinement effect. Superposition of the penetrant and the nano-confinement can have potential implications for many technological applications, such as protective and functional coatings, sensors, microelectronics, surface modification and membrane separations. In-situ ellipsometry is a powerful optical technique for the characterization a films in contact with penetrants, due to its high precision and non-invasive character. This thesis explores the applicability of the technique to study fundamentals of various physical phenomena occurring in thin and ultra-thin polymer films in the presence of interacting penetrants. The investigated macromolecular systems include model glassy and rubbery structures, PS and PDMS respectively, as well as zwitterionic thin films and complex composite membranes. Penetrants range from water, aqueous salt solutions and liquid organic solvents, to high pressure fluids. Significant attention is dedicated to the superposition of nano-confinement and penetrant effects on the equilibrium and dynamic properties of the investigated systems. These combined impacts are of particular importance in membrane separations.