Pillared Carbon Membranes Derived from Cardo Polymers

Abstract

Carbon molecular sieve membranes (CMSMs) were prepared by carbonizing the high free volume polyimide BTDA-BAF that is obtained from the reaction of benzophenone-3,3′,4,4′-tetracarboxylic dianhydride (BTDA) and 9,9-bis(4-aminophenyl) fluorene (BAF). The bulky cardo groups prevented a tight packing and rotation of the chains that leads to high permeabilities of their CMSMs. The incorporation of metal–organic polyhedra 18 (MOP-18, a copper-based MOP) in the BTDA-BAF polymer before pyrolysis at 550 °C prevented the collapse of the pores and the aging of the CMSMs. It was found that upon decomposition of MOP-18, a distribution of copper nanoparticles minimized the collapse of the graphitic sheets that formed the micropores and mesopores in the CMSM. The pillared CMSMs displayed CO2 and CH4 permeabilities of 12,729 and 659 Barrer, respectively, with a CO2/CH4 selectivity of 19.3 after 3 weeks of aging. The permselectivity properties of these membranes was determined to be at the 2019 Robeson upper bound. In contrast, the CMSMs from pure BTDA-BAF aged three times faster than the CMSMs from MOP-18/BTDA-BAF and exhibited lower CO2 and CH4 permeabilities of 5337 and 573 Barrer, respectively, with a CO2/CH4 selectivity of 9.3. The non-pillared CMSMs performed below the upper bound.

Carbon fiber composite electrodes derived from metal organic polyhedra-18 and matrimid for hybrid supercapacitors

“…The surface area of the electrode materials increased after adding MOP-18 due to porosity generated by the decomposition of MOP-18 at high temperatures. 56,73–75 The surface areas for 2 : 1 and 1 : 2 carbonized and activated Matrimid/MOP-18 were 268 m 2 g −1 and 564 m 2 g −1 , respectively. Fig.…”

“…The solid precipitate was left to crystallize for 24 h at room temperature and then washed repeatedly with methanol at room temperature. 56 The blue solid was dried at 60 °C for 24 h. The product MOP-18 crystals were characterized by powder XRD (Fig. S1, ESI†).…”

“…In the outer shell, MOP-18 contains 24 dodecyl alkane chains, and in the inner core, it consists of 24 copper atoms in 12 paddle-wheel units. 55,56 The long carbon chains attached to the structure render MOP-18 highly soluble in a variety of organic solvents which aided mixing with Matrimid polymer during electrospinning. MOP-18 was uniformly dispersed in the composite nanofiber, which afforded small copper and copper oxide nanoparticles after carbonization.…”

MOP−18−Derived CuO Fiber for Hybrid Supercapacitor Electrodes

“…MOP−18 has an inner core comprising 24 copper atoms arranged in 12 paddle−wheel units. The organic outer layer has 24 dodecyl groups attached to it [ 23 , 24 ]. This long alkyl chain outer structure gives MOP−18 exceptional solubility in several organic solvents, ensuring a uniform dispersion in the fibers produced by the electrospinning process.…”