Polymers are used in a plethora of applications where the diffusion of water, solvents, gases, or other small molecule penatrants needs to be controlled. In some applications, such as reverse osmosis water filtration membranes or fuel cell membranes, the selective transport of a specific species needs to be facilitated. In other examples, such as barrier coatings or polymer matrix composites, the transport of specific species should be inhibited. In this research opportunity we explore the fundaments of small molecules or gas transport through a polymeric materials. Particular topics of interest include studying the thermodynamic  interaction of the diffusing species with the polymeric host, exploring dynamic or kinetic coupling between the polymer matrix and the diffusing species, and elucidating the role of the mechanical properties and swelling stresses that the penetrant induces on the polymer matrix and how these stresses in turn influence solubility and diffusivity.  This research opportunity is particularly interested understanding how these properties change when the polymer is confined in a thin film or an interphase that would be found in a composite.