Flue gas carbon dioxide emissions from coal-based power plants are suggested as a factor causing climate change. Membrane is an attractive technology for the capture of carbon dioxide from flue gas. Matrimid® asymmetric hollow fiber membranes with “homogeneous dense” and “fused nodular” selective layers were successfully formed. The PDMS post-treated nodular-skinned fibers showed better cold performance than the dense-skinned fibers with bore side feed. A hypothesis with regards to increased sorption capacity coupled with orientated polymer chain segments for the nodular skin was proposed and supported by indirect evidences. Based on the understanding of CO2 and N2 transport in cold Matrimid® hollow fiber membranes, a second generation of cold membranes with superior performance was developed. The high free volume, rigid 6FDA/BPDA-DAM hollow fiber membranes with both dense and nodular selective layers were successfully formed as well, which showed similar selectivity but much higher permeance than the high performing nodular Matrimid® hollow fiber membranes at cold conditions.