(351bd) Fabricating Freestanding Thin-Film Membranes with Carbon Nanodots Via Layer-By-Layer Assembly

The application of membranes in liquid and gas separation is attractive because of their energy efficiency. Synthesis of novel membranes with well-defined microstructure is necessary to achieve highly permeable and selective membranes for separation processes. Recently, carbon-based materials such as carbon nanodots, graphene, and carbon nanotubes have emerged as an exciting class of nanomaterials due to their unique topologies and tailorable functionalities. Incorporation of these nanomaterials in the membranes has shown to improve the performance. Carbon nanodots (CNDs) have shown great promise in many applications because of their low toxicity, biocompatibility, and photoluminescent behavior. Here, we report the fabrication of highly crosslinked membranes by using aminated CNDs as a building block for organic nanoseparation applications. These CNDs are synthesized from m-phenylenediamine by using a solvothermal method. We use a layer-by-layer framework to obtain nanoscale membranes by covalently crosslinking trimesoyl chloride and CNDs. The synthesized membranes are stable in various organic solvents and have manifested high selectivity (up to 90%) and permeability for dye molecules such as brilliant blue and disperse red in methanol. As the CNDs synthesized here are fluorescent under UV light, the resultant film is also fluorescent. This property can be harnessed for diagnostic purposes, such as tracking mechanical failure and fouling of the membranes.