The objective of Subtask 6.5 is to develop and test superior gas separation membranes. Several methods are to be tested to prepare new membrane materials, including physical vapor deposition via electron beam evaporation. The selectivity of these membrane materials for separating undesired gases was to be determined. Selectivity will be measured by feeding the gases to the membrane and sampling the inlet, permeate, and raffinate streams for gas composition and volumetric flow rate.