Understanding How Molecules Permeate Through Solid Substances

The purpose of this paper is to describe how molecules in a fluid move (permeate) through a solid material. The paper will describe permeation on a molecular level and discuss the general relationships between different types of fluids and difFerent forms of solid materials. A general understanding of the behavior of molecules at the fluid/solid interface should be useful to engineers responsible for selecting permeation resistant materials. As a specific example, the interaction of various automotive fuel mixtures and fluoropolymer barrier materials will be presented.