A method of separating a mixture of N (N.gtoreq.2) gases by size exclusion,
comprising:
contacting the mixture of gases with N-1 gas permeable porous films, each
of the N-1 gas permeable porous films being made of a permeable porous
material including pores of different sizes, formed with at least one
nanostructured compound. wherein the at least one nanostructured compound
includes 30% or more polyhedral oligomeric silsequioxane (POSS) by weight:
wherein at least one of the N-1 gas permeable porous films has pores which
do not allow permeation of at least one of the N gases.