Microporous adsorbents for CO2 capture – a case for microporous polymers?

Combining theory and experiment for X-ray absorption spectroscopy and resonant X-ray scattering characterization of polymers

“…For example, the nitrogen K edge can be used to quantify orientation in a planar conjugated polymer [43], as shown in Figure 2. In this case, nitrogen atoms are only present on the [1,2,5]thiadiazole [3,4-c]pyridine moiety in the backbone making NEXAFS simulations, peak assignment and orientation analysis less complicated.…”

“…In the simplest case of polymers of intrinsic microporosity (PIMs), the membrane is composed of a neat polymer, and the contrast is derived between the polymer and vacuum (which comprises the pores when under vacuum conditions for measurement). These porous polymers and their very small (<2 nm) intrinsic pores are ideal structures for gas storage and separation [5,7]. Essentially, the neat polymer comprises the matrix and provides mechanical integrity to the membrane, while the 'unoccupied' volume that arises from imperfect packing of rigid polymer backbones serves as the 'highways' for transport of ions, gas, or water, depending on the chemistry of the polymer.…”

“…These include flexible electronics [1][2][3][4], gas separations [5][6][7], polymer electrolytes for batteries, fuel cells and water desalination [8][9][10], and lithographic patterning [11][12][13] just to name a few. It has remained challenging to fully understand the relationships between chemistry and structure, and the growing demand to characterize polymers under in situ or in operando conditions relevant to a specific application and as a function of time creates additional challenges.…”

Ultramicroporous CO2 adsorbents with tunable mesopores based on polyimines synthesized under off-stoichiometric conditions

“…Here, it is worthwhile noting that the uptake of CO 2 at 0 C for the PPs varied less than the low pressure uptake of N 2 at À196 C. This difference indicates that several of the samples had a porosity that was not fully accessible at a lower temperature to N 2 . For example, even though its low specific surface area as determined by adsorption of N 2 at À196 C, PP2-1 had a significant uptake of CO 2 at 0 C. It is not uncommon that sorbents with ultramicropores [6], exhibit large uptake of CO 2 and kinetically reduced uptake of N 2 [44,45]. Hence, studying the adsorption of CO 2 at relatively high temperatures is a suitable approach to probe such ultramicropores [46].…”

NMR studies of methane and hydrogen in microporous materials

“…The efficiencies of various nanoporous and microporous materials for storage and ease of removal depend crucially on the thermodynamic properties of these gases at or near the surfaces of the chosen materials [8][9][10][11][12]. These properties and the characteristic dynamics are also important in the development of methods for CO 2 sequestration [13][14][15]. There is considerable documentation in the literature about the total absorption properties of light gases (such as hydrogen and methane) on various porous materials but there is little information about the detailed dynamics of the gases in the confined geometries or about their interactions with the walls of the confinement.…”