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Crystals of a metal–organic framework, UiO-66, are grown on electrospun crosslinked poly-cyclodextrin (poly-CD) fibrous membranes with an ultrahigh coverage, and polyaniline (PANI) is further confined within the MOF pores. The obtained PANI@UiO-66/poly-CD membranes are used as free-standing electrodes towards use in wearable energy-storage devices. [ABSTRACT FROM AUTHOR]

Portable and flexible energy devices demand lightweight and highly efficient catalytic materials for use in energy devices. An efficient water splitting electrocatalyst is considered an ideal future energy source. Well‐aligned high‐surface‐area electrospun polymers of intrinsic microporosity (PIM‐1)‐based nitrogen‐doped carbon nanofibers were prepared as a free‐standing flexible electrode. A non‐noble‐metal catalyst NiOOH/Ni(OH)2 was precisely deposited over flexible free‐standing carbon nanofibers by using atomic layer deposition (ALD). The morphology, high surface area, nitrogen doping, and Ni states synergistically showed a low onset potential (ηHER=−40 and ηOER=290 mV vs. reversible hydrogen electrode), small overpotential at η10 [oxygen evolution reaction (OER)=390.5 mV and hydrogen evolution reaction (HER)=−147 mV], excellent kinetics (Tafel slopes for OER=50 mV dec−1 and HER=41 mV dec−1), and high stability (>16 h) towards water splitting in an alkaline medium (0.1 m KOH). The performance was comparable with that of state‐of‐the‐art noble‐metal catalysts (e.g., Ir/C, Ru/C for OER, and Pt/C for HER). Post‐catalytic characterization with X‐ray photoelectron spectroscopy (XPS) and Raman spectroscopy further proved the durability of the electrode. This study provides insight into the design of 1D‐aligned N‐doped PIM‐1 electrospun carbon nanofibers as a flexible and free‐standing NiOOH/Ni(OH)2 decorated electrode as a highly stable nanocatalyst for water splitting in an alkaline medium. A simple and controlled synthesis of flexible, free‐standing, binder‐free, atomically deposited NiOOH/Ni(OH)2 on well‐aligned N‐doped PIM‐CF and its application towards overall water splitting (i.e., hydrogen evolution reaction and oxygen evolution reaction) in an alkaline medium. [ABSTRACT FROM AUTHOR]

Polymers of intrinsic microporosity (PIMs) are among the most promising candidates for the development of novel polymeric gas separation membranes for processes such as carbon capture and storage, natural gas treatment and biogas upgrading. As one of the approaches to optimize their performance, PIMs are functionalized by CO 2 -philic groups to improve the CO 2 separation by the enhancement of specific noncovalent interactions. In this work, we show the preparation of amine-PIM from the archetypal PIM-1, using borane dimethyl sulphide complexes in order to control the degree of conversion. The PIM-1 to amine-PIM-1 conversion was characterized by ATR-IR and NMR analysis. The influence of the amine moiety on the gas transport behaviour was investigated by two complementary techniques: gas permeation measurements by the time lag method and analysis of the sorption kinetics and the equilibrium sorption isotherms by the gravimetric method. Both techniques show that permeability decreases with increasing degree of conversion. The trends in the indirectly calculated solubility confirm those of direct analysis, although quantitative comparison of the two shows fundamental differences. A pressure and temperature study on a fully converted sample indicates that the solution-diffusion model should be expressed in concentration dependent transport parameters to be correct. The experimental work was supported by quantum mechanics studies and by molecular dynamics simulations to confirm the selective non-covalent interaction of CO 2 with the amino groups. [ABSTRACT FROM AUTHOR]

The polymer of intrinsic microporosity PIM-1 was modified by reaction with ethanolamine and with diethanolamine, and the modified polymers characterized by infrared spectroscopy, solid-state NMR spectroscopy, elemental analysis, thermogravimetric analysis and nitrogen adsorption. Various possible reaction products were considered, and the results indicated that hydroxyalkylaminoalkylamide structures were obtained. Gas adsorption measurements showed that ethanolamine modification increased the ideal CO2/N2 selectivity. Studies of dye adsorption from aqueous solution demonstrated that the reaction products showed strong selectivity for the anionic dye Orange II, compared to the cationic dye Safranin O. Mass uptakes of the anionic dye by ethanolamine-modified PIM-1 samples were up to 2 orders of magnitude higher than for the parent polymer. [ABSTRACT FROM AUTHOR]

Synthesis of nitrogen-doped carbon fibers (CF) has been proved to be one of the most promising oxygen reduction reaction (ORR) catalysts which can replace the state-of-art Pt catalyst for non-noble metal-free light-weight devices. Polymers of Intrinsic Microporosity (PIM-1) is soluble in common organic solvents and can be tailored by functionalization owing to nitrile groups in the backbone. PIM-1 was functionalized to amide (hydrolyzed PIM-1), amine and amidoxime groups. The modified PIM-1s were electrospun into ultrafine fibers and pyrolyzed to obtain CF. The present article investigates the influence of different functional groups on the properties of PIM-1 based CF and their nitrogen-doping. Particularly, their ORR performance has been evaluated. Interestingly, CF from hydrolyzed PIM-1 have the highest pore volume with small pore size among the CF based on PIM-1, amine and amidoxime PIM-1. The amount of nitrogen-doping in these CF shows the trend according to the functional groups as PIM-1 > amine > amidoxime > amide. Among all these PIM-1 based CF; CF from hydrolyzed PIM-1 has the highest percentage of pyridinic and graphitic nitrogen, furthermore, electrocatalysis revealed that ORR processed through four-electron with the onset potential 985 mV vs. reversible hydrogen electrode (RHE) which is comparable with the standard Pt/C catalysts. Image 1 • Electrospinning of amide, amine and amidoxime based PIM-1 fibers. • Synthesis and characterization of N-doped carbon fibers from electrospun fibers. • Influence of functional groups in the fibers towards oxygen reduction reaction. • Position of nitrogen and conductivity of fibers are crucial towards ORR catalysis. [ABSTRACT FROM AUTHOR]

This manuscript describes the gas separation performance of PIM-2, a partially fluorinated linear copolymer synthesized from 5,5′,6,6′-tetrahydroxy-3,3,3′,3′-tetramethylspirobisindane (TTSBI) and decafluorobiphenyl (DFBP). As one of the early members of the family of polymers of intrinsic microporosity, it had never been tested as a gas separation membrane because of insufficient mechanical resistance. This has been solved only recently, allowing the preparation of robust self-standing films. Molecular modelling studies demonstrated a high fractional free volume (34%) and an elevated surface area (642 m2 g−1), and the latter is in good agreement with experimental BET results. Pure gas permeabilities measured on a fixed-volume time-lag instrument at 1 bar compare well with the results of mixed separation tests on a variable volume setup from 1-6 bar(a). Molecular modelling and independent sorption measurements on a gravimetric sorption balance both show strong dual-mode sorption behaviour, especially for CO 2 and to a lesser extent for CH 4. Temperature-dependent pure gas permeation measurements show typical Arrhenius behaviour, with a clear increase in the activation energy for diffusion with the increasing molecular size of the gas, indicating high size-selectivity. This is in agreement with the highly rigid PIM structure, determined by AFM force spectroscopy measurements. The dual-mode behaviour results in a moderate pressure dependence of the CO 2 permeability and the CO 2 /N 2 and CO 2 /CH 4 selectivity, all slightly decreasing with increasing pressure. The presence of humidity in the gas stream has a remarkable small effect on the membrane performance, which is probably due to the high fluorine content and the consequently low water vapour solubility in the polymer, as confirmed by gravimetric sorption measurements. The manuscript describes an extensive study on the structure-property relationships in PIM-2. Image 1 • Fluorinated PIM-2 forms robust self-standing membranes. • CO 2 /N 2 and CO 2 /CH 4 mixed gas separation data lie close to the 2008 upper bound. • Separation performance is hardly affected by the presence of humidity in the feed gas. • Water sorption is very low due to the hydrophobic nature of the fluoropolymer. • MD simulations show how halogen bond networks enhance the energetic diffusion selectivity. [ABSTRACT FROM AUTHOR]

In the present study, bio‐based benzoxazine resins were synthesized from bio‐based phenolic compound; thymol, and three different amines; ethylamine, aniline and 1,6‐diaminohexane, and paraformaldehyde by solvent‐free condensation reaction. The chemical structures of bio‐based benzoxazines; T‐ea (thymol, ethylamine), T‐a (thymol, aniline), and T‐dh (thymol, 1,6‐diaminohexane) were characterized by proton nuclear magnetic resonance spectroscopy, Fourier transform infrared (FTIR) spectroscopy, elemental analysis, and high‐resolution mass spectrometry. The curing studies of T‐ea, T‐a, and T‐dh bio‐based benzoxazines were performed by stepwise thermal treatment at 150, 175, 200, 225, and 250 °C. The polymerization (ring‐opening and crosslinking reactions) of T‐ea, T‐a, and T‐dh bio‐based benzoxazines was investigated by FTIR spectroscopy. Cure analysis was conducted using differential scanning calorimetry and the changes in thermal properties of the T‐ea, T‐a, and T‐dh bio‐based benzoxazine resins and their corresponding thermally crosslinked polybenzoxazines PT‐ea, PT‐a, and PT‐dh were studied by thermogravimetric analyzer. The results indicated that all the thymol‐based polybenzoxazines have shown enhanced thermal stability. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47371. Bio‐based benzoxazine resins were synthesized from a plant derived phenolic compound thymol (T), paraformaldehyde, and three different amines with different functionalities; ethyl amine (ea, aliphatic), aniline (a, aromatic), and 1,6‐diaminohexane (dh, difunctional aliphatic). After thermal curing of all thymol‐based bio‐benzoxazines, opening and crosslinking of the oxazine ring was achieved and their polybenzoxazines (PT‐ea, PT‐a, and PT‐dh) were obtained with good thermal stability. [ABSTRACT FROM AUTHOR]

In this study, thermally crosslinked hydrolyzed polymers of intrinsic microporosity (HPIM)/polybenzoxazine electrospun nanofibrous membranes (NFMs) are successfully produced. The nanofibers having 800 ± 260 to 670 ± 150 nm average fiber diameters from HPIM and blends of HPIM/ benzoxazine (BA‐a) ranging from HPIM:(BA‐a) weight ratio of 9:1 to 2:1 w/w are produced by electrospinning. Self‐standing HPIM/(BA‐a) NFMs are thermally step‐wise cured resulting in crosslinked HPIM/Poly(BA‐a) NFMs. Structural characterization of as‐electrospun HPIM/(BA‐a) and crosslinked HPIM/Poly(BA‐a) NFM is conducted by FT‐IR spectroscopy to trace the ring opening and crosslinking reactions. Elemental analysis and XPS studies show an increase in carbon content and reduction in nitrogen content due to the crosslinking reaction. Decomposition temperature (Td) of HPIM NFM increases from 218 to 270 °C with the crosslinking based on the DSC. DMA analysis shows that the mechanical strength of the NFMs has increased significantly with crosslinking. Young's moduli of HPIM NFM is increased from 16 ± 7 to 67 ± 1 MPa for crosslinked HPIM/Poly(BA‐a)%33 NFM. Similarly, higher storage modulus is observed for HPIM/Poly(BA‐a) NFMs compared to HPIM NFM. The crosslinked HPIM/Poly(BA‐a) NFMs keep their fibrous morphology after solvent treatment in dimethylformamide revealing their structural stability compared to pristine HPIM NFM. Electrospun hydrolyzed polymers of intrinsic microporosity (HPIM) nanofibrous membranes (NFMs) are successfully crosslinked with benzoxazine monomer (BA‐a) to improve mechanical, thermal, and structural properties of the HPIM NFM. [ABSTRACT FROM AUTHOR]