Sub-nm Pore Size of Phenylethynyl End-Capped Imide Oligomer-Derived Carbon for Molecular Sorption and Separation

Carbon molecular sieves (CMSs) derived from polymer precursorsthat can be prepared at scale are attractive for various energy-efficientsorption and separation technologies, such as hydrogen recovery, airpurification, and hydrocarbon separation. Preparing CMSs with uniformsub-nm pores is prudent but rarely studied. Here, we report the useof phenylethynyl-terminated crosslinkers to control pore size, leadingto highly uniform pore formation between 6 and 7 & ANGS;. We demonstratethat incorporating phenylethynyl-terminated functionalities into thermallyrearrangeable (TR) imide oligomers with asymmetric chemical structuresresults in CMSs with consistent pore sizes (6-7 & ANGS;), highsurface areas (up to 775 m(2)/g), and excellent CO2 sorption performance (3.17 mmol CO2/g of CMS). Additionally,our results indicate that sub-nm pore formation can be further tailoredthrough polymer network architecture, leading to variable surfaceareas (569-735 m(2)/g), which is accomplished throughcomposition control of polymer precursors with and without TR capabilities.The fundamental understandings about the impact of the molecular designof phenylethynyl-terminated polymer precursors on their derived carbonstructure can provide critical insights into their rational designfor future molecular sorption and separation applications.