Carbon nanotube based mixed matrix membranes with supramolecularly engineered interface for enhanced gas separation performance
Abstract In this study, novel nanocomposite membranes were fabricated from single walled carbon nanotubes (SWNTs) and a triptycene containing polyimide. The desirable interfacial morphology and homogenous dispersion of SWNTs were achieved by strong p p stacking and supramolecular shape fitting interactions between the nanotube and the paddlewheel shaped triptycene moieties in polymer matrix. Mixed matrix membranes (MMMs) containing 2 15 wt% of as purchased SWNTs (AP SWNTs) were prepared and tested for their gas transport properties. While all MMMs showed greatly enhanced permeabilities with well maintained selectivities, a non linear dependence of permeability on filler content was observed. Another series of MMMs with purified SWNTs (P SWNTs) and acid treated SWNT (A SWNTs) were also prepared. The functionalized A SWNT MMM exhibited the best separation performance at 2 wt% filler content among all MMMs, which can be attributed to the improved interfacial affinity with carboxylic acid functionalized surface of A SWNTs.