| The effectiveness of many chemical engineering processes is improved by increasing the active area available for heat or mass transfer per unit volume. This thesis explores the application of block copolymers, which have large interfacial areas in self-assembled structures, to gas separation membranes.; The membrane proposed in this thesis consists of a poly(isoprene-b-styrene-b-dimethylsiloxane) (ISD) triblock copolymer. A series of ISD triblock copolymers was synthesized with varying volume fractions. The morphologies of both the neat triblock copolymers, and binary and ternary blends of triblock copolymers with low molecular weight homopolymers, were studied. Lamellar, core-shell cylinder, and core-shell gyroid morphologies were identified in these materials using a combination of small-angle x-ray scattering (SAXS), transmission electron microscopy (TEM), and modeling.; The core-shell gyroid structure in an ISD triblock copolymer or blend is applicable to the proposed membrane because the selective, glassy polystyrene block separates the rubbery polyisoprene and polydimethylsiloxane blocks at every point. Calculations of the performance of an ISD triblock copolymer membrane indicated that the membrane must be thin (<1 μm) to be selective. For this thickness the flux through an ISD triblock copolymer membrane is predicted to be approximately five times the flux through a composite membrane of the same projected area. |
