Visual indicator for trace organic volatiles

Sorption-Induced Fiber Optic Plasmonic Gas Sensing via Small Grazing Angle of Incidence

Sensing technologies based on plasmonic nanomaterials are of interest for various chemical, biological, environmental, and medical applications. In this work, an incorporation strategy of colloidal plasmonic nanoparticles (pNPs) in microporous polymer for realizing distinct sorption-induced plasmonic sensing is reported. This approach is demonstrated by introducing tin-doped indium oxide pNPs into a polymer of intrinsic microporosity (PIM-1). The composite film (pNPs-polymer) provides distinct and tunable optical features on the fiber optic (FO) platform that can be used as a signal transducer for gas sensing (e.g., CO2 ) under atmospheric conditions. The resulting pNPs-polymer composite demonstrates high sensitivity response on FO in the evanescent field configuration, provided by the dramatic response of modes above the total-internal-reflection angle. Furthermore, by varying the pNPs content in the polymer matrix, the optical behavior of the pNPs-polymer composite film can be tuned to affect the operational wavelength by over several hundred nanometers and the sensitivity of the sensor in the near-infrared range. It is also shown that the pNPs-polymer composite film exhibits remarkable stability over a period of more than 10 months by mitigating the physical aging issue of the polymer.

Polymers of Intrinsic Microporosity Based on Dibenzodioxin Linkage: Design, Synthesis, Properties, and Applications

The development of polymers of intrinsic microporosity (PIMs) over the last two decades has established them as a distinct class of microporous materials, which combine the attributes of microporous solid materials and the soluble nature of glassy polymers. Due to their solubility in common organic solvents, PIMs are easily processable materials that potentially find application in membrane-based separation, catalysis, ion separation in electrochemical energy storage devices, sensing, etc. Dibenzodioxin linkage, Tröger's base, and imide bond-forming reactions have widely been utilized for synthesis of a large number of PIMs. Among these linkages, however, most of the studies have been based on dibenzodioxin-based PIMs. Therefore, this review focuses precisely on dibenzodioxin linkage chemistry. Herein, the design principles of different rigid and contorted monomer scaffolds are discussed, as well as synthetic strategies of the polymers through dibenzodioxin-forming reactions including copolymerization and postsynthetic modifications, their characteristic properties and potential applications studied so far. Towards the end, the prospects of these materials are examined with respect to their utility in industrial purposes. Further, the structure-property correlation of dibenzodioxin PIMs is analyzed, which is essential for tailored synthesis and tunable properties of these PIMs and their molecular level engineering for enhanced performances making these materials suitable for commercial usage.

Pentaerythritol: A Versatile Substrate in Organic Transformations, Centralization on the Reaction Medium

BACKGROUND

Pentaerythritol (2,2-bis (hydroxymethyl) propane-1,3-diol) as white crystalline odorless solid has been synthesized in 1891. Pentaerythritol is multifaceted species in many compounds, which are wildly utilized in medicine and industry. Also, multicomponent reactions (MCRs) play a crucial role in organic and medicinal chemistry. Hence, in these reactions, pentaerythritol is a versatile substrate for the synthesis of many polyfunctionalized products, because of the presence of the neopentane core and one hydroxyl group in each of the four terminal carbons.

OBJECTIVE

The review describes pentaerythritol multicomponent reactions in the presence of different solvents in the reaction medium to produce various compounds including pentaerythritols. This review covers the literature relevant up to 2018.

CONCLUSION

It is obvious from the provided review that a great deal of research has been done in this field, utilizing various mediums (solvent-free conditions, aqueous media, and organic solvents) for the synthesis of the products of containing pentaerythritols. This classification is based on the importance of economic and environmental friendly reactions. Due to the whole aforesaid reports, some reactions required heat for their progress, and some others were accompanied by microwave or ultrasonic waves.

Effect of Backbone Rigidity on the Glass Transition of Polymers of Intrinsic Microporosity Probed by Fast Scanning Calorimetry

Polymers of Intrinsic Microporosity (PIMs) of high performance have developed as materials with a wide application range in gas separation and other energy-related fields. Further optimization and long-term behavior of devices with PIMs require an understanding of the structure-property relationships, including physical aging. In this context, the glass transition plays a central role, but with conventional thermal analysis a glass transition is usually not detectable for PIMs before their thermal decomposition. Fast scanning calorimetry provides evidence of the glass transition for a series of PIMs, as the time scales responsible for thermal degradation and for the glass transition are decoupled by employing ultrafast heating rates of tens of thousands K s^-1. The investigated PIMs were chosen considering the chain rigidity. The estimated glass transition temperatures follow the order of the rigidity of the backbone of the PIMs.

Dispersible microporous diblock copolymer nanoparticles via polymerisation-induced self-assembly

Dispersible microporous polymer nanoparticles formed via the RAFT-PISA polymerisation of divinylbenzene and fumaronitrile using a PEG macro-CTA.

Stability of amine-functionalized CO2 adsorbents: a multifaceted puzzle

This review focuses on important stability issues facing amine-functionalized CO2 adsorbents, including amine-grafted and amine-impregnated silicas, zeolites, metal-organic frameworks and carbons. During the past couple of decades, major advances were achieved in understanding and improving the performance of such materials, particularly in terms of CO2 adsorptive properties such as adsorption capacity, selectivity and kinetics. Nonetheless, to pave the way toward commercialization of adsorption-based CO2 capture technologies, in addition to other attributes, adsorbent materials should be stable over many thousands of adsorption-desorption cycles. Adsorbent stability, which is of utmost importance as it determines adsorbent lifetime and operational costs of CO2 capture, is a multifaceted issue involving thermal, hydrothermal, and chemical stability. Here we discuss the impact of the adsorbent physical and chemical properties, the feed gas composition and characteristics, and the adsorption-desorption operational parameters on the long-term stability of amine-functionalized CO2 adsorbents. We also review important insights associated with the underlying deactivation pathways of the adsorbents upon exposure to high temperature, oxygen, dry CO2, sulfur-containing compounds, nitrogen oxides, oxygen and steam. Finally, specific recommendations are provided to address outstanding stability issues.

Membranes with Intrinsic Micro-Porosity: Structure, Solubility, and Applications

Microporous polymer membranes have been widely studied because of their excellent separation performance. Among them, polymers of intrinsic micro-porosity (PIMs) have been regarded as a potential next-generation membrane material for their ultra-permeable characteristics and their solution-processing ability. Therefore, many reviews have been reported on gas separation and monomers for the preparation of PIMs. This review aims to provide an overview of the structure-solubility property. Different structures such as non-network and network macromolecular structure made of different monomers have been reviewed. Then their solubility with different structures and different separation applications such as nanofiltration, pervaporation, and gas/vapor separation are summarized. Lastly, we also provide our perspectives on the challenges and future directions of the microporous polymer membrane for the structure-property relationship, anti-physical aging, and more.

How Do Organic Vapors Swell Ultrathin Films of Polymer of Intrinsic Microporosity PIM-1?

Dynamic sorption of ethanol and toluene vapor into ultrathin supported films of polymer of intrinsic microporosity PIM-1 down to a thickness of 6 nm are studied with a combination of in situ spectroscopic ellipsometry and in situ X-ray reflectivity. Both ethanol and toluene significantly swell the PIM-1 matrix and, at the same time, induce persistent structural relaxations of the frozen-in glassy PIM-1 morphology. For ethanol below 20 nm, three effects were identified. First, the swelling magnitude at high vapor pressures is reduced by about 30% as compared to that of thicker films. Second, at low penetrant activities (below 0.3p/p₀), films below 20 nm are able to absorb slightly more penetrant as compared with thicker films despite a similar swelling magnitude. Third, for the ultrathin films, the onset of the dynamic penetrant-induced glass transition P_g has been found to shift to higher values, indicating higher resistance to plasticization. All of these effects are consistent with a view where immobilization of the superglassy PIM-1 at the substrate surface leads to an arrested, even more rigid, and plasticization-resistant, yet still very open, microporous structure. PIM-1 in contact with the larger and more condensable toluene shows very complex, heterogeneous swelling dynamics, and two distinct penetrant-induced relaxation phenomena, probably associated with the film outer surface and the bulk, are detected. Following the direction of the penetrant's diffusion, the surface seems to plasticize earlier than the bulk, and the two relaxations remain well separated down to 6 nm film thickness, where they remarkably merge to form just a single relaxation.

Tetraphenylethylene-based microporous organic polymers: insight into structure geometry, porosity, and CO2/CH4 selectivity

Tetraphenylethylene-based microporous organic polymers with tunable porosities were synthesized and their gas sorption capabilities were investigated.

A unique 3D ultramicroporous triptycene-based polyimide framework for efficient gas sorption applications

A novel 3D ultramicroporous triptycene-based polyimide framework with high surface area (1050 m² g⁻¹) and high CO₂ sorption capacity (3.4 mmol g⁻¹ at 273 K and 1 bar), good CO₂/N₂ (45) and CO₂/CH₄ (9.6) selectivity was synthesized and characterized.

Base-catalysed hydrolysis of PIM-1: amide versus carboxylate formation

Controlled hydrolysis of PIM-1 yields polymers tailored for the selective adsorption of ionic dyes.

Polymers of Intrinsic Microporosity

This paper focuses on polymers that demonstrate microporosity without possessing a network of covalent bonds—the so-called polymers of intrinsic microporosity (PIM). PIMs combine solution processability and microporosity with structural diversity and have proven utility for making membranes and sensors. After a historical account of the development of PIMs, their synthesis is described along with a comprehensive review of the PIMs that have been prepared to date. The important methods of characterising intrinsic microporosity, such as gas absorption, are outlined and structure-property relationships explained. Finally, the applications of PIMs as sensors and membranes for gas and vapour separations, organic nanofiltration, and pervaporation are described.

Optical sensor for diverse organic vapors at ppm concentration ranges

A broadly responsive optical organic vapor sensor is described that responds to low concentrations of organic vapors without significant interference from water vapor. Responses to several classes of organic vapors are highlighted, and trends within classes are presented. The relationship between molecular properties (vapor pressure, boiling point, polarizability, and refractive index) and sensor response are discussed.

Laser chemosensor with rapid responsivity and inherent memory based on a polymer of intrinsic microporosity

This work explores the use of a polymer of intrinsic microporosity (PIM-1) as the active layer within a laser sensor to detect nitroaromatic-based explosive vapors. We show successful detection of dinitrobenzene (DNB) by monitoring the real-time photoluminescence. We also show that PIM-1 has an inherent memory, so that it accumulates the analyte during exposure. In addition, the optical gain and refractive index of the polymer were studied by amplified spontaneous emission and variable-angle ellipsometry, respectively. A second-order distributed feedback PIM-1 laser sensor was fabricated and found to show an increase in laser threshold of 2.5 times and a reduction of the laser slope efficiency by 4.4 times after a 5-min exposure to the DNB vapor. For pumping at 2 times threshold, the lasing action was stopped within 30 s indicating that PIM-1 has a very fast responsivity and as such has a potential sensing ability for ultra-low-concentration explosives.