Gyroid Membranes made from Nanoporous Blck Copolymers

Nanoporous materials are interesting and exciting materials in view of their many potential applications, especially as ultrafiltration membranes. One way of preparing nanoporous polymeric materials is to use block copolymers. Block copolymers have the great advantage that they organize them-selves into different morphologies on the nano scale. Block copolymer synthesis controls the molecular weight and volume fraction of blocks, which determine the resulting nano-structures. From a membrane application point of view one very suitable morphology is the bicontinuous gyroid. Mechanical stability of the membrane and its nanoporosity is e.g. obtained by cross-linking the majority blocks and selectively etching the minority blocks. Here we report on ultrafiltration membranes prepared from a 1,2-polybutadiene-b-polydimethylsiloxane diblock copolymer with gyroid structure. Different experimental methods are used to characterize the morphology, find the pore diameter, pore size distribution and internal surface area (Small Angle X-Scattering, Scanning Electron Microscopy, Transmission Electron Microscopy and Nitrogen Adsorption). The performance of these gyroid membranes is evaluated by investigating gas and liquid fluxes as well as the separation of molecules of different molecular weights.