Modification of gas-selective properties of polymer membranes by thin film deposition and carbon ion implantation

Effect of H+and N+Irradiation on Structure and Permeability of the Polyimide Matrimid®

“…The evolution in chemical structure will result in a corresponding modification in the polymer microstructure through a combination of formation of crosslinks and small molecular size defects resulting from release of small molecules. This would result in a shift in the overall polymer fractional free volume, free volume distribution as well as chain mobility, thus modifying gas transport properties of the polymeric membrane (17)(18)(19)(20)(21)(22)(23). For example, positron annihilation spectroscopy of N þ irradiated polyimide indicated that there was both an increase in free volume and the generation of a new population of defects (i.e.…”

“…Post-synthesis methods that modify the structure and microstructure of existing polymeric membranes to optimize the gas transport properties are attractive alternatives to new polymer synthesis. These methods include thermal treatment (4-7), fluorination (8)(9)(10), plasma treatment (11)(12)(13)(14)(15), and ion beam irradiation (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). Ion beam irradiation allows selective modification of the chemical structure, microstructure and properties of polymers.…”

“…Numerous studies have reported development of polymeric membrane materials that have attractive gas separation properties (i.e., high gas permeability and high permselectivity) combined with thermal and mechanical stability (1)(2)(3). These studies mainly focus on (i) synthesis of polymers designed using structure-property relationship (1)(2)(3)(4)(5)(6)(7), and (ii) development of alternative membrane materials and=or modification of existing polymeric membranes using diverse post-synthesis techniques (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26).…”

Impact of H+ ion irradiation on Matrimid®. I. Evolution in chemical structure

“…Although selective alterations of transport characteristics through chemical synthesis have resulted in improved membrane materials, polymers appear to be reaching an upper bound trade‐off between permeability and selectivity 12. Therefore, the focus of much recent research has been on developing alternative membrane materials and/or postformation techniques for modification of existing polymeric membranes 13–30…”

“…There are a number of postsynthesis methods that can be used to modify gas permeation properties of polymers, including thermal treatment,13, 14 fluorination,15–18 and plasma treatment 19–21. Ion beam irradiation is a very effect method that has recently been used to modify the selective layer of polymeric membranes 22–29. In addition, the recently developed plasma immersion ion implantation (PIII)30 offers many advantages over conventional beamline ion implantation including the ability to implant complex shaped surfaces combined with a lower capital and operating cost.…”