Micro‐Phase Separation within Epoxy Resin Yields Ultrathin Mesoporous Membranes with Increased Scalability by Conversion from Spin‐ to Dip‐Coating Process

Abstract

Ultrathin mesoporous membranes offer highly desirable characteristics for separation tasks regarding selectivity and mass transport of proteins. They have potential applications as separation devices in microfluidics, diagnostics, sensing, and high‐precision separations for pharmaceutical formulation. Especially for large‐scale and mass production, sophisticated production processes represent a barrier for wider application. A method is developed to produce nanomembranes with a thickness of 75 nm and 40 nm pores with an epoxy resin. The novolac resin is cured with branched polyethylenimine to form a covalently crosslinked polymer membrane with perforations spanning the entire thickness. Pore formation relies on micro‐phase separation of the curing agent during casting and the selective dissolution of the emergent nanodomains which thereby serve as pore templates. The resulting membranes are hydrophilic and therefore suitable for applications with biological fluids. Mechanical testing of the flexible but robust thin films reveals an ultimate tensile strength of 15 MPa and a biaxial modulus of 0.8 GPa. Proteins with a diameter of less than 12 nm can diffuse through the pores and permeation rates are pH dependent. The entire fabrication process is transferred to a dip‐coating approach, which is more suitable for a potential large‐scale production.

Magnetic Precipitation: A New Platform for Protein Purification

“…Although most ABC approaches are not new concepts, they are currently being re‐adapted for the purification of biopharmaceuticals. The non‐chromatographic methods used in ABC include membrane separation methods, [ 6 ] aqueous two‐phase systems, [ 7–9 ] magnetic separation, [ 10–12 ] precipitation, and crystallization. [ 5,13–15 ]…”