Molecularly imprinted polymer (MIP) technology and its prospective used in the surveillance of the environment are the focus of this review article, which aims to give an in-depth understanding of the field. The approach of generating highly cross-linked polymeric structures with effective binding sites that precisely match the analyte of interest by templating with it is covered in the study as a means of producing biomimetic ligands. It also highlights the stability and robustness of MIPs, making them ideal for challenging environmental conditions. The originality of this paper lies in its exploration of various physical forms and synthesis techniques of MIPs, as well as the development of specialized MIPs to address specific challenges. It emphasizes the diverse applications of MIPs in environmental monitoring, including sample pretreatment, solid-phase extraction, microextraction, sensors, and chromatographic separations with the discussion on integration of MIPs with advanced analytical tools, highlighting the potential for enhancing the accuracy and reliability of environmental monitoring. Furthermore, the integration of MIPs with advanced analytical instruments opens up new possibilities for qualitative and quantitative evaluation of detection systems. Capillary electrochromatography and thin-layer chromatography are mentioned as the examples of analytical techniques that can be seamlessly integrated with MIPs. This integration enables improved accuracy and reliability in environmental monitoring, enhancing our understanding and protection of the environment. It not only explores the fundamentals of MIP technology but also delves into the synthesis methods, specialized MIPs, and integration with advanced analytical instruments. By providing this holistic view, the paper offers a valuable resource for researchers and practitioners interested in utilizing MIPs for environmental monitoring applications.
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A study of the self-healing capabilities of 2-aminophenyl disulfide (AFD)/epoxy systems is carried out. It has been observed that an excess of AFD promotes an increase of both the storage modulus and the glass transition temperature (Tg) due to an increase of the cross-link density. Concerning the self-healing properties, every AFD/epoxy system shows very good healing efficiencies (above 90%) with no prevalent differences among the different stoichiometries. Furthermore, CNT addition induces an increase of the storage modulus when there is no excess of AFD, but no significant effect is observed on the Tg. In addition, the incorporation of these nanoparticles allows thermal activation by the Joule effect. The results of self-healing tests under convective and resistive heating show similar healing efficiencies (all above 94%). Here, the thermal activation by Joule’s heating presents a lower power consumption and allows localized repair, which is very promising for this type of application.
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The application of ordinary epoxy resins is severely limited by their poor dielectric properties and toughness, and the increasing focus on sustainability calls for raw materials to be renewable. Thus, a resveratrol-based compound (AE-Res) with three active ester structures was prepared and used to cure glycidyl ethers of bisphenol A (DGEBA) and a liquid crystal epoxy monomer (BPDGE). Test results showed that the combination (AE-Res/BPDGE) of resveratrol derivatives with liquid crystal epoxy monomers exhibited an excellent comprehensive performance. The mechanical strength and toughness of AE-Res/BPDGE were improved. Specifically, the tensile strength, elongation at break, flexural strength, and impact strength of AE-Res/BPDGE were 108.45 MPa, 12.31%, 159.92 MPa, and 39.51 kJ/m2, which were 48.14, 164.16, 92.51, and 143.74% higher than that of BPDGE cured by commercial methylhexahydrophthalic anhydride (MHHPA), respectively. This can be attributed to the introduction of a rigid structure and flexible ether bonds generated after curing. Meanwhile, the dielectric constant (Dk) of AE-Res/BPDGE decreased from 3.81 to 3.00 (10 MHz) compared to MHHPA/BPDGE, mainly owing to the enhanced d-spacing (4.69 vs 4.45 Å) and the absence of highly polar hydroxyl groups. In addition, AE-Res/BPDGE also exhibited good thermal stability and hydrophobicity with a T5% of 383.22 °C, a water contact angle of 110°, and a water absorption of 0.15% because of the presence of a rigid conjugated stilbene and biphenyl structure. Due to its ease of synthesis and environmental friendliness, AE-Res could be a satisfactory alternative to commercial epoxy curing agents.
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Cyclic oligomers of hexamethylene furanoate and hexamethylene terephthalate were obtained from 1,6-hexanediol and the corresponding methyl esters using Candida antarctica lipase B (CALB) enzyme catalyst. HPLC, MALDI-TOF MS, and NMR analyses showed that mixtures composed from cyclic dimer up to heptamer were obtained almost quantitatively. Subsequently, these cycles were polymerized by ring opening polymerization (ROP) mediated by CALB to obtain semicrystalline polymers. In addition, we demonstrated that the polymers obtained from the ROP process could be transformed into cyclic oligomers in high yields using enzymatic cyclodepolymerization, thereby recycling the polymer in a circular biosynthetic path.
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A piperazine-linked robust N-rich covalent organic polymer (COP), SMCOP-1, was synthesized by a catalyst-free method and characterized by Fourier transform infrared (FTIR), 13C CP/MAS, X-ray photoelectron spectroscopy (XPS), and powder X-ray diffraction (PXRD). This polymeric material can work as an efficient platform for removing toxic Hg2+ from wastewater. This system showed >97% Hg2+ removal, as confirmed by inductively coupled plasma atomic emission spectroscopy (ICP-AES), with a maximum uptake capacity of 1329 mg g–1. Hg2+ incorporation inside SMCOP-1 was confirmed by XPS, energy-dispersive spectrometry (EDS), and elemental mapping of field emission scanning electron microscopy (FE-SEM). The high Hg2+ removal capacity of SMCOP-1 can be attributed to the strong noncovalent interaction between the Hg2+ ion and the binding sites of the covalent organic polymer, as suggested by density functional theory (DFT) calculations, noncovalent interaction (NCI) analysis, and the electrostatic potential (ESP) map. The material’s recyclability was studied for up to four consecutive cycles, and it was observed that it retained a high removal capacity without any change in the structure and morphology, as confirmed by FTIR and FE-SEM.
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The mechanism involving the curing process of bisphenol A diglycidyl ether (DGEBA) used as an epoxy prepolymer (EP) by the phosphonium ionic liquid, denoted trihexyl (tetradecyl) phosphonium decanoate (P66614[dec]), was investigated by differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. The main mechanisms of the opening of epoxy groups inducing the polymerization were modeled through the reaction between a model substrate, i.e., phenyl glycidyl ether (PGE), and the ionic liquid (IL) by using “in situ” 13C and 31P NMR spectroscopy. DSC analysis revealed the latency characteristics of this system. FTIR and size exclusion chromatography analyses confirmed the chain-growth polymerization by an anionic route with the formation of an ether linkage. The combined FTIR and NMR techniques for the EP/P66614[dec] and PGE/P66614[dec] systems suggest a dual polymerization mechanism involving the initiation with the carboxylate counter anion and also the Wittig ylide generated during the heating process of the IL. The epoxy network cured with this system presents higher glass-transition temperatures (134–155 °C) by using a small amount of IL. The liquid nature of the IL and its low vapor pressure allow the development of epoxy networks with environmental safety and easy processing, making these systems very promising for employing as coatings, adhesives, and other applications.
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N-Nitrosamine-derived nitric oxide (NO) delivery agents find widespread use in diverse biomedical applications, including cancer therapy. To understand how NO is released from these compounds and acts within cells, herein, we report a facile approach to synthesize N-nitrosamine-bound water-soluble napthalimide-based block copolymers (BCPx-NO) with improved regulation over their molecular weight and aqueous solution self-assembly. These polymers exhibit a fluorescence “turn-on” response upon photostimulated (365 nm, 3.71 mW/cm2) NO release, delivering 47–53 μM of NO within 10 h, while their concentration varied from 0.26 to 0.60 mg/mL. This accounts for approximately 67–75% of the theoretically bound NO within the polymers. The fluorescence “turn-on” response is characteristic of the small-molecule NO donor (NOD), although the emission time has a longer half-life in the polymers. The type of NO released from the NOD is a nitric oxide radical (•NO), as per the electron paramagnetic resonance spectroscopy results. The in vitro NO release in response to the photoirradiation and the consequent acquired fluorescence are corroborated using flow cytometry and confocal imaging studies. It was also manifested that these NO conjugated polymers can physically encapsulate doxorubicin (DOX) in aqueous environment, and the synergistic effect of DOX and NO is reflected in the exhibited cytotoxicity against the MCF-7 (human breast adenocarcinoma) cells. The spatiotemporally modulated NO release steered fluorescence “turn-on” may find abundant biomedical applications.
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