Nanostructured polymer membranes for fast and selective gas transport Sunshine Iguodala , Qilei Song Department of Chemical Engineering, Imperial College London, SW7 2AZ UK The urgency of addressing climate problems has led to increased attention on the separation and storage of greenhouse gases. Polymer-based membrane separation has proven to be a cost-effective and energy- efficient technology for large-scale gas separation, compared to traditional separation processes. 1 Conventional membrane materials achieve high gas selectivities but suffer from poor gas permeability due to inherent material limitations.Although novel polymers with both solution processability and microporosity show great potential as next-generation membranes, creating thin film composite (TFC) membranes with high gas permeance remains a difficult task.
Figure 1: Schematic cross-section of a TFC membrane The key to designing a high-performing gas separation TFC membrane is to develop a highly gas-permeable gutter layer and an ultrathin selective top layer. While nanoscale selective layers have been recently developed, achieving high gas permeance is still difficult due to the lack of control over the gutter layer, as the thickness of the gutter layer often exceeds the target thickness due to the partial filling of pores in the supporting layer. Polydimethylsiloxane (PDMS) is a commonly used material for gutter layers due to its high gas permeability. In this poster presentation, we report the fabrication, characterisation and testing of a crosslinked aminopropyl- terminated PDMS (NH 2 -PDMS-NH 2 ) gutter layer coated unto a porous polyacrylonitrile (PAN) support, that consistently achieves relatively high CO 2 permeances >11,500 GPU while maintaining selectivity. The PDMS gutter layer serves to provide a uniform, flat surface to accommodate an ultrathin selective layer, overcoming the uneven surfaces of the porous substrate that would otherwise reduce gas permeance. For the development of the selective layer, we also report the one-step synthesis of solution-processible fluorinated polymers of intrinsic microporosity (F-PIMs) with a tuneable degree of fluorination, that may allow us to modify the hydrophobicity of the thin film for advanced gas separation, where the presence of water may negatively affect membrane performance. Forthcoming efforts will be geared towards evaluating the performance of the F-PIM/NH 2 -PDMS- NH 2 /PAN TFC membrane. References 1. Han and W.S. W. Ho, J. Membr. Sci ., 2021, 628, 119244
P83F
Made with FlippingBook Learn more on our blog