Rapidly Ordered Block Copolymer Membranes with Tunable Pore Sizes for Wastewater Treatment

The present surface water resources will soon be insufficient to meet the needs of the next generations. Wastewater is now contaminated with oil and other organic compounds due to the rapid rise in oil and gas, petrochemical, pharmaceutical, and food processing industries. Membranes present an easy and energy-efficient solution for removing both particulates and oily matter from wastewater. Here we present a methodology to rapidly order block copolymer thin films with well-defined through-thickness channels having minimal tortuosity. The technique involves casting BCP films from solution mixtures doped with selective plasticizing additives that segregate into one of the BCP domains. Owing to the selectivity and plasticization capability of the additive and the preferential solvation of BCP components in the solvent mixture, the film is fully ordered in the casting process. With careful selection of the casting environment, completely perpendicular domain morphologies with variable domain sizes can be achieved for high fluxes and tunable pore sizes. These films are supported by commercial membranes like PES and treated to selectively crosslink one and etch the other block to open the pores. The film microstructure is characterized via atomic force microscopy and x-ray scattering. At the same time, the membrane performance is tested using a dead-end cell and UV-vis spectroscopy.