Empty space and how things move around in it

All matter contains pockets of empty space. Solubility and transport properties of polymers and other amorphous materials are highly dependent on the character of this free volume. Surprisingly little has been done to characterize these void spaces. Previous research has characterized free volume in terms of geometric tessellations, and spherical cavities, and calculates distributions of the sizes of these cavities. Two polymers might have the same overall free volume, yet exhibit vastly different free volume distributions, with accompanying differences in solubility and diffusivity relative to a particular penetrating species. These differences are due in part to differences in the size distributions of cavities, but the connectivity of the voids also plays an important role. Current free volume models are extended, and new multiscale probability models are introduced.