Microporous Polymers: Synthesis, Characterization, and Applications

Abstract

The present article gives an overview on current developments in the area of microporous polymers, that is polymers that have permanent pores of sizes below 2 nm. Basic concepts of the synthetic procedures are reviewed, and latest developments are discussed. Special interest is placed on developments that allow the synthesis of microporous polymers in well‐defined macroscopic morphologies such as particles, membranes, or monolithic structures. The various possibilities of microporosity characterization are discussed. Concepts adopted from the polymer membrane community such as positron annihilation lifetime spectroscopy or the zeolite community ( 129 Xe‐NMR, gas adsorption), as well as modern molecular modeling approaches are discussed. The various findings are combined, and open questions (which are still present in the field of microporous polymers) are pointed out. Latest developments regarding the application of microporous polymers in various technologies, ranging from adsorption science to optoelectronic and energy‐related applications are discussed finally. A critical comparison to other microporous materials such as zeolites or carbon is given, whenever appropriate.

Structure of Polytetrafluoroethylene Modified by the Combined Action of γ-Radiation and High Temperatures

“…Possibly, the smectic phase can also be formed on the walls of lamella, as well as pores in PTFE. Then, a decrease in the intensity of diffraction maxima 107 and 108 in the X-ray spectra of TRM-PTFE (Table 1, Figure 4a,b) may be attributed to a decrease in the content of the smectic phase in the composition of PTFE due to the disappearance of pores [51] and the transformation of lamellae into fibrils [52]. This conclusion is confirmed by the scanning electron microscopy data [53], which indicate that irradiation at temperatures exceeding 200 °C leads to the thickening of lamellae in PTFE and to the formation of a fibrillar structure.…”

“…Possibly, the smectic phase can also be formed on the walls of lamella, as well as pores in PTFE. Then, a decrease in the intensity of diffraction maxima 107 and 108 in the X-ray spectra of TRM-PTFE (Table 1, Figure 4a,b) may be attributed to a decrease in the content of the smectic phase in the composition of PTFE due to the disappearance of pores [51] and the transformation of lamellae into fibrils [52].…”

“…This agrees with the conclusion made in [50], where the nature of halo II was attributed to the presence of low molecular weight impurities in the polymer. Possibly, the origin of halo II can be attributed to the presence of pores also (more accurately, to the presence of a smectic phase on the surface of pore walls) [51].…”

Emulsion-Templated Monoliths Based on PIM-1 Monomers: Hierarchical Porosity and Dye Adsorption

“…3 Most microporous materials, whether inorganic or organic in nature, are insoluble powders. 4 Polymers of intrinsic microporosity (PIMs) are synthesized using rigid and twisted monomers that contain steric groups to prevent the conformational changes that would enable better packing. 5 The poor macromolecular packing in PIMs produces microporosity 6,7 and makes them of interest for gas sorption, 8 separation, 9 and hydrogen storage.…”

Waterborne Colloidal Polymer/Silica Hybrid Dispersions and Their Assembly into Mesoporous Poly(melamine-formaldehyde) Xerogels

“…Micro- and mesoporous organic polymers, i.e., polymers having pore sizes below 2 or 50 nm, respectively, have received a great deal of attention during the past decade. They potentially combine the high porosities, which are well known from activated carbons or zeolites, with the light weight, the good processability, and the broad range of functionalities that are well known from polymer science, resulting in potential applications ranging from adsorption technology to biomedical and optoelectronic applications. − …”