Material and transport properties of fluids in nanoconfining systems

The phenomenological description of nature is challenged when material is dimensionally constrained. Statistical properties are altered and interfacial properties become increasingly important in the study of material and transport properties of fluids at interfaces. This thesis work is concerned about three distinct categories of confinement that appear in many engineering applications such as fuel cell technology and tribology: (a) “structuring effects” in liquids in the vicinity to interfaces, (b) fluid flow through nano-porous membrane systems, and (c) environmentally induced transitions in transport systems during operation.; First I will discuss some rheological methods that have been used to determine structuring effects. This part will involve capillary force measurements and a discussion of critical parameters for capillary neck formation. Then, I will introduce a rate-method that is based on friction force microscopy, to determine the degree of entropy losses of simple fluids (e.g., n-hexadecane) in the close-vicinity to ultra-smooth solid surfaces. A thermodynamic activation model is used to interpret the rate data in terms of a cohesive interaction length. Finally, I will introduce novel nanoscopic approaches to study in-situ transport properties of permeates in the vicinity of the transport systems and their material properties. Systems that will be discussed include Nafion polymers, used in fuel cells.