We have already showed that thin epoxy films with aligned flakes can have permeabilities which are as much as 100 times lower than that of the original epoxy. Such films may find application in paint. However, these films often are brittle and inelastic, a consequence of a volume fraction of flakes as high as 30 percent. Now, we are combining silicone rubber and up to 80 percent flakes to get a composite with the mechanical properties of the original epoxy, but a permeability which is 1000 times smaller. These new composites can be made by chemical vapor deposition and by directed self-assembly.