Synthesis and Characterization of PSf-CQD Nanocomposite Membrane via Non-solvent Induced Phase Separation Technique

Abstract

AbstractMembranes have been widely used in separation and purification technologies. With a broad range of polymers for membrane applications, polysulfone (PSf) has been a research interest due to its high thermal strength, solubility in a variety of aprotic polar solvents, and chemical durability over a wide pH range. However, PSf is hydrophobic in nature. Thus, researchers are incorporating fillers that enhance the hydrophilicity of PSf for the desired applications in filtration and sensing. Carbon quantum dots (CQD) are highly hydrophilic. Hence, CQDs are potential fillers in PSf. PSf membranes with varying concentrations of CQD (0.50, 1.0, and 2.0 wt%) were successfully fabricated via NIPS and characterized. PSf pellets (15 wt% and 18 wt%) are dissolved in N-methyl pyrrolidone (NMP) and casted onto a glass substrate. Membranes were formed by coagulating the dope solution in distilled water. FTIR and SEM results show that CQD was incorporated into the PSf polymer matrix. At 15% PSf concentration, pore sizes of the membranes have almost the same magnitude as membranes with CQD loading up to 2.0%. At 18% PSf concentration, the pore sizes significantly increased at 2.0% CQD loading. For both 15 wt% and 18 wt% PSf, addition of CQDs improved the hydrophilicity of the membranes. Furthermore, there is an increase in stiffness of the 15% PSf membrane with CQD loading of 2.0% and an increase in stiffness of the 18% PSf membrane at 1.0% CQD loading. The results show that PSf/CQD membrane may be useful in filtration or sterilization applications.KeywordsCarbon Quantum DotsPolysulfone MembraneNon-solventInduced Phase Separation