COMBINING BLOCK COPOLYMERS WITH METAL OXIDES FOR EFFICIENT PROTEIN SEPARATION

Block copolymers (BCPs) are considered promising materials for various membrane applications ranging from water purification to protein separation due to their ability to self-assemble into highly ordered structures with uniform pore size. Typically, the pore’s size and surface interactions can be controlled by the BCP chemistry. However, simultaneous control over both properties is difficult to achieve. This is, in particular, important for separation of same sized proteins, which is currently done by a multi-step process.

In this study, we use poly (styrene-block-methyl methacrylate) (PS-b-PMMA) based membranes and apply several post-fabrication processes to create efficient protein separation membranes. By using sequential infiltration synthesis (SIS), an atomic layer deposition based technique that enables selective growth of metal oxides inside the polar domains of BCP, Al₂O₃ was grown inside the PMMA domains in porous PS-b-PMMA films (Figure 1). Structural characterization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) was used to correlate between the selective growth of metal oxide and the pore size of the hybrid film and showed that the pore surface is composed of polymer- Al₂O₃. The control over the pore size as well as the pore surface chemistry will enable tailored separation of desired proteins using both size exclusion and affinity exclusion.

Figure 1 - A schematic overview of the membrane fabrication process