Porous Polymer Research Articles

Reinforced MOF/polymer composite based on a copper metal-organic framework supported on nanoporous hyper cross-linked polycalix[4]resorcinarene for the preparation of phthalazine and 4H-pyran heterocycles

The present study has aimed to prepare a novel MOF/polymer composite called PC4RA@PrSi-CA/Cu-MOF to take benefit from the advantages of both Cu-based metal-organic framework (Cu-MOF) and porous polymer based on Cis-calix[4]resorcinarene (PC4RA). Various processes, including preparation of a 3D network of polycalix, modification of polycalix with (3-aminopropyl)trimethoxysilan (APTMS) and citric anhydride (CA), and functionalization of the modified polymer with Cu-MOF nanostructure, respectively, were used for synthesizing MOF/polymer composite. Next, the characterization and confirmation of the polymer-supported Cu-MOF were analyzed using FT-IR, EDS-Mapping, STA, PXRD, FE-SEM, and TEM techniques. In the continuation, two types of heterocycles, including phthalazines and 4H-pyrans, were synthesized to reveal the efficiency of the PC4RA@PrSi-CA/Cu-MOF nanocomposite. The catalyst showed a reasonable performance by providing a satisfactory yield of the desired products (90–99 %) during a short time (8–20 min) under mild and green conditions (50 °C in H2O). Furthermore, the structure of the heterocycles was validated using FT-IR, 1H/13C NMR. Then, the catalyst was successively reused ten times in the model reaction and studied using FT-IR, EDX, TEM, and elemental mapping analyses to demonstrate the catalyst stability in recoverability. According to the results, this heterogenized catalyst can recover several times without a notable drop in stability and activity.

Superlative Porous Organic Polymers for Photochemical and Electrochemical CO2 Reduction Applications: From Synthesis to Functionality.

To mimic the carbon cycle at a kinetically rapid pace, the sustainable conversion of omnipresent CO2 to value-added chemical feedstock and hydrocarbon fuels implies a remarkable prototype for utilizing released CO2. Porous organic polymers (POPs) have been recognized as remarkable catalytic systems for achieving large-scale applicability in energy-driven processes. POPs offer mesoporous characteristics, higher surface area, and superior optoelectronic properties that lead to their relatively advanced activity and selectivity for CO2 conversion. In comparison to the metal organic frameworks, POPs exhibit an enhanced tendency toward membrane formation, which governs their excellent stability with regard to remarkable ultrathinness and tailored pore channels. The structural ascendancy of POPs can be effectively utilized to develop cost-effective catalytic supports for energy conversion processes to leapfrog over conventional noble metal catalysts that have nonlinear techno-economic equilibrium. Herein, we precisely surveyed the functionality of POPs from scratch, classified it, and provided a critical commentary of its current methodological advancements and photo/electrochemical achievements in the CO2 reduction reaction.

Resistive Memristors Using Robust Electropolymerized Porous Organic Polymer Films as Switchable Materials.

Porous organic polymers (POPs) with inherent porosity, tunable pore environment, and semiconductive property are ideally suitable for application in various advanced semiconductor-related devices. However, owing to the lack of processability, POPs are usually prepared in powder forms, which limits their application in advanced devices. Herein, we demonstrate an example of information storage application of POPs with film form prepared by an electrochemical method. The growth process of the electropolymerized films in accordance with the Volmer-Weber model was proposed by observation of atomic force microscopy. Given the mechanism of the electron transfer system, we verified and mainly emphasized the importance of porosity and interfacial properties of porous polymer films for memristor. As expected, the as-fabricated memristors exhibit good performance on low turn-on voltage (0.65 ± 0.10 V), reliable data storage, and high on/off current ratio (104). This work offers inspiration for applying POPs in the form of electropolymerized films in various advanced semiconductor-related devices.

Solar-powered porous polymer materials-enabled rapid atmospheric water harvesting and storage of liquid water

Atmospheric water harvesting (AWH) is emerging as a promising strategy to produce fresh water from abundant airborne moisture to reduce the global clean water shortage. Hydrogels are considered attractive adsorbents due to their higher water retention and tunable polymer-water interactions. Here, we report the super hygroscopic polymer material (SHPMs) using modified NH2-MIL-101(Cr) as a functional crosslinker by copolymerization with acrylic acid and 2-Acrylamide-2-methylpropanesulfonic acid, achieving a water uptake of about 28.8–49.7 mg/g at 28–38 % RH. The material can desorption quickly under sunlight, and the desorbed water can be stored in a polymer skeleton for use by vegetation or crops during periods of water demand. Besides, the Water retention and storage performance and its outdoor experiment also proved that the application of this material in agriculture, forestry and desertification control laid the foundation to improve the effective availability of soil moisture and water harvesting and conservation. With its excellent water retention and atmospheric water harvesting performance, the material offers a sustainable method for rapid water extraction in arid climates.

Incorporating porous carbon materials into ionic liquid for high efficiency extraction of polycyclic aromatic hydrocarbons

Ionic liquid is an ideal candidate in the extraction of aromatic compounds. The design and construction of ionic liquids with high extraction efficiency and selectivity towards to the specific aromatics remain crucial question. In this paper, with the aid of orthogonal array experiment, the imidazolium-based ionic liquids with long alkyl chain on the cations were determined to possess high aromatics extraction efficiency. Furthermore, the Lewis acid anion was introduced into the ionic liquid to form 1-dodecyl-3-methylimidazolium ferric chloride ([C12mim][FeCl4]) and performed 62 % and 100 % extractant efficiency of naphthalene (NAP) and anthracene (ANT), respectively. Then the porous carbon materials (P1-1000) derived from hyper-crosslinked porous polymers (HCP) which possessed high BET surface area (1186 m2/g) was dispersed in [C12mim][FeCl4] to form porous ionic liquid. The single extraction efficiency of NAP improved from 62 % to 77 %. The great single extraction efficiency was attributed to the high porosity, additional adsorption sites provided by the Lewis acid anions and the hydrophobic long alkyl chain on the cations. After three times extraction, the concentration of NAP dropped down to 0. The porous ionic liquids also showed good recycle performance. The construction of porous ionic liquids provided an efficient approach for extraction of polycyclic aromatic hydrocarbons from aliphatic hydrocarbon.

Three Birds with One Sulfur: Construction of Sulfur-Bridged Porous Organic Polymers for Efficient Gold Adsorption.

Sulfur is a massive byproduct of the petrochemicals industry and hardly employed as a building block for porous organic polymers (POPs). Here, a new family of sulfur-bridged POPs has been prepared via a C-H insertion reaction between sulfur and polycyclic aromatic hydrocarbons. Sulfur works as a solvent, external cross-linker, and porogen simultaneously during the polymerization process. The products demonstrate high porosity and maximum surface area of 1050 m2 g-1 with abundant accessible active sites, contributing to the nanometerization of sulfur and significantly enhancing the inherent affinity between heteroatoms toward soft metal ions. Therefore, they exhibit a high absorption capacity for Au(III) of 3287 mg g-1 and excellent absorption selectivity and removal efficiency via a performance evaluation even in real electronic wastewater. This synthetic strategy to prepare high added-value functional POPs with sulfur not only sheds light on designing high-performance gold adsorption materials and emerging POPs, but also promotes a sustainable development protocol.

Highly Active Cu@NC Catalyst Derived from Porous Organic Polymer for Solvent‐Free Coupling of Acyl Chlorides with Alkynes

Highly Active Cu@NC Catalyst Derived from Porous Organic Polymer for Solvent‐Free Coupling of Acyl Chlorides with Alkynes

Carbon Dioxide Capture by Emerging Innovative Polymers: Status and Perspectives.

A significant amount of research has been conducted in carbon dioxide (CO2) capture, particularly over the past decade, and continues to evolve. This review presents the most recent advancements in synthetic methodologies and CO2 capture capabilities of diverse polymer-based substances, which includes the amine-based polymers, porous organic polymers, and polymeric membranes, covering publications in the last five years (2019 to 2024). It aims to assist researchers with new insights and approaches to develop innovative polymer-based materials with improved capturing CO2 capacity, efficiency, sustainability, and cost-effective, thereby addressing the current obstacles in carbon capture and storage to sooner meeting the net-zero CO2 emission target. This article is protected by copyright. All rights reserved.

Porous polymer beads with grafted poly(tertiary amine) as catalysts for fixation of carbon dioxide into propylene carbonate

Porous polymer beads with grafted poly(tertiary amine) as catalysts for fixation of carbon dioxide into propylene carbonate

In situ fabrication of porous polymer films embedded with perovskite nanocrystals for flexible superhydrophobic piezoresistive sensors

The application of pressure sensors based on perovskite in high-humidity environments is limited by the effect of water on their stability. Endowing sensors with superhydrophobicity is an effective strategy to overcome the issue. In this work, MAPbBr3/Polyvinylidene Fluoride-TFSI composite was prepared by a one-step in-situ strategy to form a flexible superhydrophobic pressure sensor, which exhibited a contact angle of 150.25°. The obtained sensor exhibited a sensitivity of 0.916 in 1 kPa, a detection limit of 0.2 Pa, a precision of 0.1 Pa, and a response/recovery of ∼100 ms, along with good thermal stability. Through density functional theory calculations, it is revealed that the formation of the porosity is attributed to the interaction between the polymer and EMIM TFSI, which further leads to superhydrophobicity. And, the perovskite structure is easy to change under pressure, affecting the carrier transport and electrical signals output, which explains the sensing mechanism. In addition, the sensor performed well in monitoring facial expression, pulse, respiration, finger bending, and wind speed ranging from 1 m/s to 6 m/s. With both the Linear Regression and the Random Forest algorithm, the sensor can monitor the wind speed with an R2 greater than 0.977 in 60 tests.

Melamine sponges incorporated azo-linked porous organic polymer as adsorbent for extraction and determination of six B vitamins using pipette tip micro solid-phase extraction

A novel azo-linked porous organic polymer (AL-POP) was synthesized from caffeic acid and benzidine via an azo-coupling reaction and characterized by FTIR, SEM-EDS, BET, TGA, XRD and zeta potential analysis. AL-POPs were incorporated into melamine sponges and used for pipette tip micro solid-phase extraction (PT-MSPE) of six types of B vitamins (including thiamine, riboflavin, nicotinamide, pyridoxine, folic acid, and cyanocobalamin). After extraction, the samples were analyzed using high performance liquid chromatography-diode array detection (HPLC-DAD) system. The effect of AL-POP composition on the extraction efficiency (EE) of vitamins was investigated and benzidine to caffeic acid mol ratio of 1.5, 3.35 mmol of NaNO2, and reaction time of 8 h were selected as optimum conditions. The efficiency of the extraction process was improved by optimizing various parameters such as the amount of sorbent, pH and ionic strength of the sample, sample volume, number of adsorption and desorption cycles, type of wash solvent, and type and volume of eluent solvent. Linearity (R2≥0.9987), Limit of detection (LOD) (11.88-18.97 ng/mL), limit of quantification (LOQ) (39.62-63.23 ng/mL), and enrichment factor (EF) (1.27-4.31)) were obtained using calibration curves plotted under optimum conditions. Recovery values of these six B vitamins in the spiked multivitamin syrup samples varied from 80.01% to 108.35%, with a relative standard deviation (RSD) below 5.44%. Eventually, the optimized method was successfully used to extract and quantify the B vitamins in multivitamin syrup and non-alcoholic beer.

Electrochemical sensing of Pb2+, Cu2+, and Hg2+ by an aminoclay-based porous covalent organic polymer/ multi-walled carbon nanotubes modified glassy carbon electrode

We present a novel electrochemical sensor for the simultaneous detection of Lead (Pb2+), Copper (Cu2+), and Mercury (Hg2+) ions in seafood samples using differential pulse anodic stripping voltammetry (DPASV) technique. The sensor incorporates an aminoclay-based porous covalent organic polymer (AC-PCOP) derived from the polymerization of aminoclay and 1,3,5-benzenetricarboxylic acid (trimesic acid). To enhance conductivity, the AC-PCOP is combined with multi-walled carbon nanotubes (MWCNTs) and utilized for modifying the surface of the glassy carbon electrode (GCE). The AC-PCOP was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, and infrared spectroscopy (IR). These analyses confirmed the presence of a hierarchical architecture in the AC-PCOP, which exhibited a spherical shape. The proposed modifier facilitates the deposition-stripping process and electron diffusion between electrolyte and heavy metal ions. Optimized conditions yielded limit of detections (LODs) of 0.0006, 0.0016, and 0.0003 nM, with linear ranges from 0.002 to 1000 nM, 0.005 to 1000 nM, and 0.001 to 1000 nM for Pb2+, Cu2+, and Hg2+, respectively. The sensor successfully measured these ions in seafood samples. Control experiments and validation were performed using cold vapor atomic absorption spectrometry (CVAAS) to determine the ions in the chosen food samples.

Chemical crosslinking porous polymers prepared by thiol-ene click reaction with two-sided MXene layers for highly efficient infrared stealth

As the capabilities of infrared detection advance, materials with a single working modes are no longer sufficient for the effect. Designing a multi-module cooperative infrared stealth composite material has become particularly important. However, materials with multiple working modules face challenges such as long procession and difficulty in integration. Therefore, we employed thiol-ene click reaction to prepare porous polymers as thermal insulation substrates, incorporated phase change microcapsules for heat absorption and temperature delay, and loaded two MXene layers at the top and bottom are low emissivity for infrared stealth and radiative heating, respectively. This sandwich-structured composite material exhibits a minimum infrared emissivity of 0.289 (3–5 μm) and 0.212 (8–14 μm), showing excellent camouflage capability for infrared thermal signals under an infrared camera, generating a temperature difference of about 61 °C with the hot target at 100 °C. Additionally, the bottom MXene layer used for radiative heating can raise the temperature of artificial skin by 2.5 °C. Furthermore, the as-prepared M28PP0.36M6 also demonstrates superior mechanical properties (300 kPa, 50 %). We believe that, due to the synergistic effects of temperature control and low emissivity, combined with advantages of facile preparation, it will become a promising candidate in the field of infrared stealth.

CTAB modified metakaolin-based geopolymer microspheres for the selective adsorption and recovery of TcO4−/ReO4−

With the increase of radioactive wastewater, it is a major challenge to efficient removal of TcO4− from radioactive wastewater. So far, cationic metal organic frameworks (MOFs), cationic covalent organic frameworks (COFs), cationic polymeric networks (CPNs) and porous organic polymer materials (POPs) can remove TcO4− efficiently, but the cumbersome preparation process and high cost limit their practical applications. Herein, an efficient and low-cost CTAB-modified metakaolin-based geopolymer microspheres (CTAB@MGMs) with excellent adsorption properties for ReO4− is simply and rapidly synthesized by dispersion-pelletizing-solidification and vacuum infusion methods. CTAB@MGMs has fast adsorption kinetics (equilibrium in 10 min), a wide pH application range (2–10) and high selectivity in competing ions (PO43−, SO42−, NO3−, Cl−) and real waters (tap water, surface water, seawater). Importantly, complete desorption of the adsorbed sample can be realized by ethanol and MGMs can be recycled without performance decay. Meanwhile, ethanol recycling was achieved by spin-evaporation of desorption solution and a novel compound CTA-ReO4 was generated. We have analyzed and reported the crystal structure of CTA-ReO4 (CCDC Numbers: 2282273) for the first time and revealed the mechanism that ReO4− is removed by electrostatic and coordination synergism with quaternary ammonium salts after ion exchange. CTAB@MGMs is a low-cost, novel and reusable adsorbent with potential use for the removal of TcO4− from radioactive wastewater.

Effective Iodine Adsorption and Storage of Volatile Iodine by Nitrogen-Rich Porous Organic Polymers from Flexible Building Blocks

Effective Iodine Adsorption and Storage of Volatile Iodine by Nitrogen-Rich Porous Organic Polymers from Flexible Building Blocks

Nature-inspired wood-like TPU/CB aerogels for high performance flexible strain sensors

Strain sensors based on porous conductive polymers (CPCs) have garnered growing research interest for their potential applications in motion detection, healthcare, human–computer interaction, and artificial intelligence. However, the complexity of CPC processing makes it difficult to achieve the controlled design of microscopic porous structures, leading to simple and random porous structures, thus limiting their further use in the field of pressure sensing. This paper presents a strain sensor with a high-performance, wood-like structure composed of flexible conductive carbon black/plastic polyurethane foam (BWCT) using a bidirectional freeze casting process. The results show that, compared with conventional random freezing and unidirectional freezing, the bidirectional freeze casting process can effectively realize multiscale control of the composite structure, which results in a good laminar porous structure of the prepared BWCT. This parallel laminar structure not only contributes to the layered transfer of stresses but also avoids the local concentration of stresses. At the same time, it significantly increases the directional electrical conduction ability, which results in high sensing stability performance. In particular, the BWCT sensors had a wide detection range (80%), a lower limit of detection (0.2%), rapid response and relaxation times (200 ms), as well as exceptional durability (>2000 cycles). Furthermore, the BWCT was integrated into a wearable sensor to monitor various human motions, including arm bending, squatting, and walking, demonstrating reliable detection performance. Altogether, the BWCT sensors are promising in expanding the application but also offer guidance for designing high-performance wearable strain sensors.

Heterogeneous Porous Synergistic Photocatalysts for Organic Transformations.

Recent interest has surged in using heterogeneous carriers to boost synergistic photocatalysis for organic transformations. Heterogeneous catalysts not only facilitate synergistic enhancement of distinct catalytic centers compared to their homogeneous counterparts, but also allow for the easy recovery and reuse of catalysts. This mini-review summarizes recent advancements in developing heterogeneous carriers, including metal-organic frameworks, covalent-organic frameworks, porous organic polymers, and others, for synergistic catalytic reactions. The advantages of porous materials in heterogeneous catalysis originate from their ability to provide a high surface area, facilitate enhanced mass transport, offer a tunable chemical structure, ensure the stability of active species, and enable easy recovery and reuse of catalysts. Both photosensitizers and catalysts can be intricately incorporated into suitable porous carriers to create heterogeneous dual photocatalysts for organic transformations. Notably, experimental evidence from reported cases has shown that the catalytic efficacy of heterogeneous catalysts often surpasses that of their homogeneous analogues. This enhanced performance is attributed to the proximity and confinement effects provided by the porous nature of the carriers. It is expected that porous carriers will provide a versatile platform for integrating diverse catalysts, thus exhibiting superior performance across a range of organic transformations and appealing prospect for industrial applications.

Sustainable metal-organic framework based paper sheet as wallpaper for passive indoor moisture control

Passive indoor moisture control is a meaningful way to reduce HVAC operation and improve building energy efficiency. Metal-organic frameworks (MOFs) have been considered one of the most promising sorbent materials for passive indoor moisture control. However, the powder form of MOF is challenging to use in the built environment. Typical shaping methods like pellets, beads, and coating can lead to problems like partial pore blocking, insufficient mechanical stability, amorphization, and low material utilization. Here, we report a new sustainable MOF paper sheet comprising 25% cellulosic fibers and 75% MOF MIL-100(Fe) powder. The porous polymer matrix provides good support and fixation for MOF particles, so it’s more applicable in the built environment. The crystalline and pore structure characteristics of the MOF in the membrane are well preserved. Hydro characteristic test results show that MIL-100(Fe) paper sheet has high water vapor uptake, S-shape isotherm, mild regeneration condition, and high MBV. Then, a numerical model was developed to calculate the relation between a material’s MBV and its thickness. MIL-100(Fe) paper sheet with the most efficient thickness was applied as wallpaper in a building energy simulation model. The simulation result shows that the MIL-100(Fe) paper sheet is promising for passive indoor moisture control. It can remove about 45%-55% of the latent cooling load in most European climate types.

Analyzing the Effects of Polymeric Dielectric Materials on Micro Capacitive Pressure Sensors: A Model Incorporating Displacement-Dependent Porosity

Recently, the extensive utilization of porous polymeric materials to amplify the sensitivity of capacitive devices is noticeable. The absence of an effective mathematical model for studying these devices has spurred the development of a comprehensive mathematical model in the current work. This model is formulated to analyze the static and dynamic behavior of systems incorporating a porous polymer dielectric material within the gap between flexible and fixed microplates. The derived nonlinear governing equations encompass the effects of electrostatic force, von-Karman nonlinear strains, and displacement-dependent porosity. Employing spatial decomposition, the resulting nonlinear algebraic equations and ordinary differential equations are leveraged to study the static and transient dynamic behavior, as well as the frequency response of the sensor using a learning approach. Two scenarios are investigated to assess the impact of various geometrical and physical parameters on sensor sensitivity one with a polymeric material and another without, each with distinct parameter values. The results reveal that the inclusion of a polymeric dielectric material increases electrostatic force but concurrently elevates the equivalent stiffness of the structure. The effectiveness of using a polymeric dielectric material is contingent upon the specific geometrical and physical properties of the sensor. Moreover, the obtained results in simplified cases are compared to existing numerical and experimental data, demonstrating a high degree of agreement. This work significantly contributes to advancing the understanding of sensors incorporating porous polymer dielectric materials and underscores their potential for enhanced sensitivity across diverse applications.

Tunable 2D Conjugated Porous Organic Polymer Films for Precise Molecular Nanofiltration and Optoelectronics.

Structural design of 2D conjugated porous organic polymer films (2D CPOPs), by tuning linkage chemistries and pore sizes, provides great adaptability for various applications, including membrane separation. Here, four free-standing 2D CPOP films of imine- or hydrazone-linked polymers (ILP/HLP) in combination with benzene (B-ILP/HLP) and triphenylbenzene (TPB-ILP/HLP) aromatic cores are synthesized. The anisotropic disordered films, composed of polymeric layered structures, can be exfoliated into ultrathin 2D-nanosheets with layer-dependent electrical properties. The bulk CPOP films exhibit structure-dependent optical properties, triboelectric nanogenerator output, and robust mechanical properties, rivaling previously reported 2D polymers and porous materials. The exfoliation energies of the 2D CPOPs and their mechanical behavior at the molecular level are investigated using density function theory (DFT) and molecular dynamics (MD) simulations, respectively. Exploiting the structural tunability, the comparative organic solvent nanofiltration (OSN) performance of six membranes having different pore sizes and linkages to yield valuable trends in molecular weight selectivity is investigated. Interestingly, the OSN performances follow the predicted transport modeling values based on theoretical pore size calculations, signifying the existence of permanent porosity in these materials. The membranes exhibit excellent stability in organic solvents at high pressures devoid of any structural deformations, revealing their potential in practical OSN applications.