pH-responsive nano-structured membranes prepared from oppositely charged block copolymer nanoparticles and iron oxide nanoparticles

Nanostructured (hybrid) membranes combining properties of inorganic and polymeric materials is an integral part of the field of separation technology. Mixed matrix membranes were prepared from oppositely charged inorganic (INPs) and polymeric (PNPs) nanoparticles using spin coating method. Four different types of PNPs were prepared. Poly(2-dimethylaminoethyl methacrylate)-b-(methyl methacrylate)) and poly((methacrylic acid)-b-(methyl methacrylate)) diblock copolymers were prepared via RAFT dispersion polymerization in ethanol at 70 °C. Quaternized poly(2-(dimethylamino) ethyl methacrylate)-b-poly (benzyl methacrylate) and poly(potassium 3-sulfopropyl methacrylate)-b-poly (benzyl methacrylate) block copolymers were prepared using aqueous RAFT emulsion polymerization method at 70 °C. The inorganic iron oxide nanoparticles (INPs) were either coated with [3-(2-Aminoethylamino)propyl] trimethoxysilane (TPED) via Dimercaptosuccinic acid (DMSA) using stab exchange. Transmission electron microscopy (TEM) and Dynamic light scattering (DLS) analysis were performed to examine the size and morphology of the prepared polymeric and inorganic nanoparticles. Scanning electron microscope (SEM) and Atomic Force Microscope (AFM) images were obtained to analyze the topography and thin film formation on the nylon support. Detailed filtration experiments were carried out to evaluate the effect of pH on the performance of the membrane.