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oai:figshare.com:article/34037264 2026-10-01T00:03:50Z category_1 category_4 category_7 category_12 category_21 category_873 category_734 portal_63 item_type_6 month_year_10_2026

Influence of Diamine Structure on Chain Packing and H2/CH4 Transport in BTDA-Based Polyimide Membranes Hyerin Park (7276904) Jeong Ju Baek (25147082) Geun Yeol Bae (2542024) Kyung Ho Choi (25147085) Byeong-Su Kim (1274664) Won-Gun Koh (1821514) Hyunwoo Bark (3338616) Gyojic Shin (25147088) Biophysics Biochemistry Medicine Cell Biology Biotechnology Chemical Sciences not elsewhere classified Biological Sciences not elsewhere classified strongly suppressed ch experimental characterizations confirmed exceptional thermal stability >- spacing 4 bonding networks create jointly influence gas 3 ′, 4 4 </ sub intermolecular hydrogen bonding bonding diamine intermolecular interactions volume characteristics technical dilemma systematically incorporating steric bulk rich matrix results highlight primarily owing performance membranes molecular mobility membranes investigated intrinsic trade hydrogen economy driven hydrogen diamine structure critical imperative combined importance chain rigidity chain packing chain mobility based polyimides backbone rigidity alongside bulky 81 among 58 å Developing high-performance membranes for H2/CH4 separation is a critical imperative for the advancement of the hydrogen economy. However, conventional polymeric membranes often suffer from the intrinsic trade-off between permeability and selectivity, as well as the technical dilemma between chain rigidity and processability. In this study, we systematically investigated polyimides based on 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) containing three structurally distinct diamines to elucidate the effects of intermolecular hydrogen bonding, steric bulk, backbone rigidity, and flexibility on H2/CH4 transport. By systematically incorporating a hydrogen-bonding diamine (DABA) alongside bulky (DAPI) and flexible (MDA) units, we established a precise structure–property relationship governing subnanometric gas transport. Experimental characterizations confirmed that DABA-driven hydrogen-bonding networks create an interaction-rich matrix with significantly contracted interchain distances (d-spacing 4.58 Å) and exceptional thermal stability (exceeding 520 °C). Gas permeation measurements showed that B-DABA exhibited the highest H2/CH4 ideal selectivity of 72.81 among the membranes investigated in this study, primarily owing to its strongly suppressed CH4 permeability. Atomistic molecular dynamics simulations indicated that free-volume characteristics and polymer-chain mobility can jointly influence gas-transport behavior. While bulky DAPI units increase free volume, their rigid indane structures restrict polymer-chain mobility, whereas the flexible MDA-containing matrix exhibits greater segmental mobility. These results highlight the combined importance of intermolecular interactions, free-volume characteristics, and molecular mobility in determining H2/CH4 transport in BTDA-based polyimides. 2026-09-30T00:00:00Z Text Journal contribution 10.1021/acsapm.6c02636.s001 https://figshare.com/articles/journal_contribution/Influence_of_Diamine_Structure_on_Chain_Packing_and_H_sub_2_sub_CH_sub_4_sub_Transport_in_BTDA-Based_Polyimide_Membranes/34037264 CC BY-NC 4.0