CO2/CH4 Pure- and Mixed-Gas Dilation and Sorption in Thin (∼500 nm) and Ultrathin (∼50 nm) Polymers of Intrinsic Microporosity
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ArticleAuthors
Ogieglo, Wojciech
Genduso, Giuseppe

Rubner, Jens
Hofmann-Préveraud de Vaumas, Jacques
Wessling, Matthias
Pinnau, Ingo

KAUST Department
Advanced Membranes and Porous Materials Research CenterPhysical Science and Engineering (PSE) Division
Chemical Engineering Program
KAUST Grant Number
BAS/1/1323-01-01Date
2020-09-23Online Publication Date
2020-09-23Print Publication Date
2020-10-27Embargo End Date
2021-09-23Submitted Date
2020-05-17Permanent link to this record
http://hdl.handle.net/10754/665324
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Show full item recordAbstract
In this work, we present (i) the dilation and refractive index variation associated with changes in film density and (ii) gas uptake of pure CO2 and CH4, as well as their equimolar mixture in thin films of two polymers of intrinsic microporosity (PIMs), that is, PIM-1 and poly(trimethylsilyl)propyne (PTMSP). A conventional low-free-volume glassy polymer, cellulose triacetate, was also investigated as the reference material. All experiments were performed with ∼50 and ∼500 nm-thick films up to partial pressures of 25 bar using in situ interference-enhanced spectroscopic ellipsometry. In all cases, film thickness reduction promoted the collapse of the frozen-in free volume. Particularly for thin PIM-1 and PTMSP films, the CO2 and CH4 pure-gas uptakes were generally lower than in bulk samples. In the most extreme case of the ultrathin ∼50 nm PTMSP film, we could detect a strikingly similar qualitative behavior to the penetrant partial molar volume and dilation in rubbery polymers. Remarkably, in PIM-1, the collapse of the frozen-in free volume seemed to be opposed by its ultra-micropores (<7 Å), which was not the case in PTMSP with larger micropores (>10 Å). In mixed-gas experiments, the refractive index response of all investigated films closely followed the trend observed during CO2 pure-gas sorption. In both thickness ranges and throughout the entire pressure range, the samples dilated less in the multicomponent environment than under the corresponding ideal pure-gas conditions. We found this phenomenon consistent with the pure- and mixed-gas uptake behavior of PIM-1 and PTMSP bulk films reported in the literature.Citation
Ogieglo, W., Genduso, G., Rubner, J., Hofmann-Préveraud de Vaumas, J., Wessling, M., & Pinnau, I. (2020). CO2/CH4 Pure- and Mixed-Gas Dilation and Sorption in Thin (∼500 nm) and Ultrathin (∼50 nm) Polymers of Intrinsic Microporosity. Macromolecules. doi:10.1021/acs.macromol.0c01163Sponsors
This work was supported by funding (BAS/1/1323-01-01) from King Abdullah University of Science and Technology (KAUST).Publisher
American Chemical Society (ACS)Journal
MacromoleculesAdditional Links
https://pubs.acs.org/doi/10.1021/acs.macromol.0c01163ae974a485f413a2113503eed53cd6c53
10.1021/acs.macromol.0c01163