Constructing CO2 transport passageways in Matrimid® membranes using nanohydrogels for efficient carbon capture

Composite membranes were fabricated by incorporating poly(N-isopropylacrylamide) nanohydrogels (NHs) into Matrimid ® 5218 matrix to improve the separation performance for CO 2 /CH 4 and CO 2 /N 2 mixtures. The membranes were characterized by a fourier transform infrared spectrometer (FT-IR), scanning electron microscopy (SEM), tensile test, dynamic mechanical analysis (DMA), X-ray diffraction (XRD), positron annihilation lifetime spectroscopy (PALS), the static contact angle and water content measurement. The incorporation of nanohydrogels increased the fractional free volume of the composite membranes, water uptake and water retention capacity. The composite membranes displayed better performance than the pure Matrimid ® membrane. The nanohydrogels homogeneously embedded in the Matrimid ® matrix acted as water reservoirs to not only provide more water for dissolving CO 2 , but also construct interconnected CO 2 transport passageways. The as-prepared Matrimid ® /NHs-20 composite membrane showed CO 2 /CH 4 and CO 2 /N 2 selectivities of 61 and 52 with a CO 2 permeability of 278 Barrer, surpassing or being close to the 2008 Robeson upper bound lines.