Polymerization Process Research Articles

Thiadiazol ligand-based laccase-like nanozymes with a high Cu+ ratio for efficient removal of tetracyclines through polymerization

A promising water treatment technology involves inducing the polymerization of organic pollutants to form corresponding polymers, enabling rapid, efficient, and low CO2 emission removal of these pollutants. However, there is currently limited research on utilizing polymerization treatment technology for removing tetracyclines from water. In this study, we synthesized a laccase-mimic nanozyme (Cu-ATZ) with a high Cu+ ratio using 2-amino-1,3,4-thiadiazole as a ligand inspired by natural laccase. The Cu-ATZ exhibited enhanced resistance to more severe application conditions and improved stability compared to natural laccase, thereby demonstrating a broader range of potential applications. The excellent catalytic properties of Cu-ATZ enabled the nanozyme to be used in the polymerization process to remove tetracyclines from water. In order to simulate actual antibiotic pollution of water bodies, tetracyclines were added to the water from sewage treatment plants. Following Cu-ATZ treatment of the water sample, the chemical oxygen demand (COD) content was found to have decreased by over 80 %. In conclusion, this study presented a novel approach for tetracycline elimination from water.

Catalyst free PET and PEF polyesters using a new traceless oxalate chain extender.

Plastic material performance is strongly correlated to the polymer's molecular weight. Obtaining a sufficiently high molecular weight is therefore a key goal of polymerization processes. The most important polyester polyethylene terephthalate (PET) and the new polyethylene furanoate (PEF) require metal catalysts and time-consuming production processes to reach sufficiently high molecular weights. Metal catalysts, which are typically antimony or tin for polyesters, end up in the plastic products which may result in sustainability and ecological challenges. When the less reactive comonomer isosorbide is introduced to produce (partly) biobased materials with enhanced thermal properties, such as polyethylene-co-isosorbide furanoate (PEIF), reaching high enough molecular weight becomes even more challenging. This study presents an easily implementable approach to produce high molecular weight PET and PEF polyesters and their isosorbide copolyesters PEIT and PEIF by coupling lower molecular weight polymer chains by the reactive diguaiacyl oxalate (DGO) chain extender. DGO is so reactive, that the use of metal catalysts can be completely avoided and it helps avoiding an extra solid-state polymerization step. In addition, DGO distinguishes itself from typical chain extenders by its ability to be completely removed from the resulting polymer, thereby avoiding the inherent drawbacks associated with typical chain extenders.

Performance stability of plastics for neutron-gamma pulse shape discrimination

The introduction of the first commercially available plastic scintillators with pulse shape discrimination (PSD) offered by Eljen Technology marked progress towards potentially replacing liquid scintillators in neutron detection. However, use of these plastics over several recent years has revealed an important flaw in these materials: the eventual degradation of scintillation light output and PSD performance. Studies described in this paper considered possible reasons for this degradation. Experiments conducted with numerous lab-prepared and commercial EJ-276 samples showed that the main factor affecting the instability is oxidation that involves highly reactive radicals generated during the polymerization process or from the further breakdown of polymer chains under oxygen/air exposure. Based on the obtained results, the stability of scintillation performance for PPO (2,5-Diphenyloxazole)-based PSD plastics has been improved through modifications of the composition via the utilization of scintillation dyes and compounds with antioxidant properties that diminish the effects of oxidation. Elements of these studies were used in the commercial production of the most recent EJ-276D PSD plastic version for fast neutron detection and 6Li-loaded plastics for thermal neutron and antineutrino detection applications. Performance projections of the new PSD plastics indicate a likely degradation of less than 10 % over 5–10 years in comparison to previous EJ-276 that might lose up to 30–40 % of the scintillation light during 1–2 years of storage or deployment under ambient conditions.

Efficient removal of per- and polyfluoroalkyl substances by a metal-organic framework membrane with high selectivity and stability

Per- and polyfluoroalkyl substances (PFAS) in water requires sufficient removal due to their extreme chemical stability and potential health risk. Membrane separation can be a promising strategy, while membranes with conventional structures used for PFAS removal often face challenges such as limited efficiency and stability. In this study, a novel metal-organic framework (MOF) membrane with local modification of polyamide (PA) was developed by introducing interfacial polymerization process during the construction of lamellar membranes with MOF nanosheets. Benefiting from the dense structure and strong negative surface charge, the PA-modified MOF membrane could effectively remove 11 types of PFAS (five short-chain and six long-chain ones with molecular weights ranging from 214.0 to 514.1 Da), especially displaying high rejections for short-chain PFAS (over 84%), along with a remarkable water permeance of 21.4 L·m⁻²·h⁻¹·bar⁻1. The membrane removal characteristics for PFAS were deeply analyzed by elucidating various rejection mechanisms, with particularly distinguishing the rejection and adsorption capacity. Moreover, the membrane stability was significantly enhanced, demonstrated by the structural integrity after 10 min of ultrasonic treatment and stable separation efficiency over 120 h of continuous filtration. With enhanced surface hydrophilicity and negative charge as well as dense membrane pores, the novel membrane also exhibited more superior anti-fouling performance compared to conventional lamellar and PA membranes, further manifesting advantages for practical applications. This work provides a promising solution for developing high-performance membranes tailored specifically for efficient PFAS removal, addressing a critical need in water treatment.

Visible light-driven photoreforming of polystyrene segmented glycopolymer architectures for enhanced hydrogen generation

In this report, a series of polystyrene segmented new glycopolymer architectures are synthesized, which are utilized in the photoreforming process to achieve a remarkable rate of hydrogen production. The primary building blocks of mono-, bi-, and tetra-functional photo-iniferter were employed in the RAFT polymerization process to design a series of block copolymer architectures using styrene and acetylated glucose methacrylate monomers. Acetylated polymer architectures exhibited higher thermal stability compared to deacetylated polymers. Deacetylated polymers showed lower Tg values than the acetylated polymers. In addition, a wide range of Tg values (55–96 °C) and variations in the Tm values of the acetylated polymers indicate the dependence on the nature of the pendant unit and macromolecular architecture. The deacetylated macromolecule, 1A-PS-b-PGMD diblock copolymer exhibits a hydrogen generation rate of ∼753 μmol/g/h with an AQY of ∼1.84% compared to that of the polystyrene segment alone (53 μmol/g/h, AQY of ∼0.02%). Within the range of possible synthesized glycopolymer architectures, linear and glucose-based triblock glycopolymers show promising activity. The kinetics of the water-splitting reaction are influenced by adjustments to both the solution's pH and the hydrophilicity of the glycomacromolecular chains.

Gelatin-based carbon quantum dot-molecularly imprinted polymer: Safe photoluminescent core-shell nano-carrier for the pH-responsive anticancer drug delivery

This study aims to synthesize a core-shell gelatin-based carbon quantum dot-molecularly imprinted polymer (MIP@g-CQD) via the precipitation free-radical polymerization process using methotrexate (MTX) as a model anticancer template. To investigate the efficiency of the prepared photoluminescent MIP@g-CQD as a pH-responsive nano-carrier, MTX was loaded into MIP@g-CQD by soaking in a drug solution and the release behavior of the loaded drug was evaluated in the necessary pH values (7.4, 5). The successful synthesis of materials was characterized using PL, TEM, FE-SEM, DLS, and FT-IR analyses. Interestingly, the created cavities in the core-shell nano-carriers can interact with the MTX molecules effectively, leading to an increase in the loading capacity. According to the obtained results from Langmuir adsorption isotherms, the imprinting factor was calculated (IF = 4.91). Also, the binding kinetics of MTX revealed the creation of particular recognition sites in the core-shell polymeric network. The MTX-loaded MIP@g-CQD displayed a low rate and limited release at the simulated physiological environment (pH 7.4, 37 °C), but it is increased at tumor tissue (pH 5, 41 °C) conditions, which can lead to long-term and sustained release of MTX in the desired target. This property of MIP@g-CQD could avoid the release of MTX in normal physiological conditions, decreasing the possible side effects of MTX drug. Owing to the existence of amide functional groups in the nano-carrier structure and its negatively charged nature, the MTT assay displayed desirable cytotoxicity against the breast cancer cell line (MCF-7) for the MTX-loaded nano-carrier. According to the obtained results, the prepared safe photoluminescent MIP@g-CQD with appropriate pH-responsivity has a high ability to be applied as an anticancer and bio-detection agent.

Ultra-Stretchable Composite Organohydrogels Polymerized Based on MXene@Tannic Acid-Ag Autocatalytic System for Highly Sensitive Wearable Sensors.

Conductive hydrogels have attracted widespread attention in the fields of biomedicine and health monitoring. However, their practical application is severely hindered by the lengthy and energy-intensive polymerization process and weak mechanical properties. Here, a rapid polymerization method of polyacrylic acid/gelatin double-network organohydrogel is designed by integrating tannic acid (TA) and Ag nanoparticles on conductive MXene nanosheets as catalyst in a binary solvent of water and glycerol, requiring no external energy input. The synergistic effect of TA and Ag NPs maintains the dynamic redox activity of phenol and quinone within the system, enhancing the efficiency of ammonium persulfate to generate radicals, leading to polymerization within 10min. Also, ternary composite MXene@TA-Ag can act as conductive agents, enhanced fillers, adhesion promoters, and antibacterial agents of organohydrogels, granting them excellent multi-functionality. The organohydrogels exhibit excellent stretchability (1740%) and high tensile strength (184kPa). The strain sensors based on the organohydrogels exhibit ultrahigh sensitivity (GF=3.86), low detection limit (0.1%), and excellent stability (>1000 cycles, >7 days). These sensors can monitor the human limb movements, respiratory and vocal cord vibration, as well as various levels of arteries. Therefore, this organohydrogel holds potential for applications in fields such as human health monitoring and speech recognition.

Synthesis of biodegradable polydisulfides from renewable resources

In this paper, we report the synthesis and preliminary characterization of polydisulfides from a renewable resource. Di-linoleic diol was first converted into dithiol via transesterification of methyl-3-mercaptopropionate catalyzed by Candida antarctica Lipase B (CALB). The kinetics of the reaction was monitored using a newly developed Thin Layer Chromatography method. The dithiol was then polymerized by Reversible Radical Recombination Polymerization (R3P), a scalable “green” polymerization process using triethylamine (TEA) catalyst, aqueous H2O2, and air. 3 wt% H2O2 yielded low molecular weight polymer, while with 30 wt% concentration DL-SS with Mn = 66,400 g/mol and polydispersity of 1.26 was obtained. 800 MHz NMR and Raman spectroscopy did not detect thiol end group signals in this polymer, indicating that it had a cyclic structure. Dithiothreitol degraded the polymer to monomer in two weeks. Full characterization of this new polymer is in progress.

Multifunctional heterostructured composite foam with 3D hierarchical network for efficient electromagnetic interference shielding

The development of multifunctional electromagnetic interference (EMI) shielding materials represents an important research direction. However, the challenge remains to develop multifunctional and high-performance electromagnetic waves (EMW) shielding materials through the effective integration of multiple functions into the materials through appropriate multicomponent strategies and ingenious microstructural design. In this study, magnetic Fe3O4 nanoparticles with polypyrrole (PPy) encapsulation were successfully assembled on melamine foam (MF) with a hierarchical structure combined with a highly conductive silver layer by in situ polymerization and cyclic immersion processes to achieve absorption-dominated electromagnetic shielding and multifunctionality. The composite benefits from good impedance matching, dielectric/magnetic losses, interfacial/dipole polarization, and internal multiple reflections and scattering due to the three-dimensional conductive network. Moreover, the high concentration of modified Fe3O4@PPy particles assembled on the MF skeleton ensures that the multifunctional heterostructured composite foams remain stable and superhydrophobic even when the surface is repeatedly abraded. At the same time, MHCF exhibits excellent thermal insulation and infrared stealth properties. This work offers new insights into the design and development of lightweight and multifunctional high-performance EMW shielding materials, while simultaneously opening up new prospects for their practical applications.

Super anti‐impact silicone elastomer with shell‐less shear thickening fluid droplets in matrix

AbstractA soft and stretchable safeguarding silicone rubber is obtained by embedding large amount of shell‐less shear thickening fluid (STF) droplets into polydimethylsiloxane (PDMS) matrix through the synergistic process of emulsification and polymerization. Feeding time and temperature are optimized to generate the efficient STFs with 72.2 wt% SiO2 and high thickening viscosity of 6340 Pa·s. The embedding process and the evolution of the shell‐less STF droplets in PDMS matrix are explored by both optical and scanning electronic microscopes. The influence of the STF content on the mechanical and anti‐impact performance of the composites is explored through tensile tests and drop hammer tests. The STF content could be as much as 75 wt%, which enhances not only the softness and stretchability (elongation at break >200%) but also the impact‐protective performance of the silicone rubber. The STF/PDMS composites covering on planar and nonplanar glass substrates demonstrate self‐adaptive protection effect by reducing the force impact peak by 35%, due to the shear thickening and energy absorption of STF in the composites. This study develops a facile and scalable method for the implantation of the STF into polymer matrix, extending the applications of STF/PDMS composites in varied fields.

Spin-dyeing of cellulose fibres with vat dyes using the Ioncell process

Estimated 20 % of global clean water pollution is attributed to textile production. Dyeing and finishing processes use an extensive amount of water and chemicals, and most of the effluents and wastewater is released into the environment. In this study, we explore spin-dyeing of man-made cellulosic fibres (MMCFs) with vat dyes using the Ioncell process, circumventing the ubiquitous use of fresh water and potentially reducing effluents streams to a great extent. Spin-dyeing is an established process for synthetic polymers but is not common for MMCFs. Regenerated cellulose fibres were produced through dissolution of dissolving pulp in the ionic liquid 1,5-diazabicyclo[4.3.0]non-5-ene acetate. The produced fibres were processed into yarn and a jersey fabric was knitted. Mechanical and colour fastness properties were tested. The fibres properties were also assessed through SEM, birefringence, and crystallinity measurements. Fibres with excellent mechanical properties (tenacity higher than 50 cN/tex) and colour fastness were produced, with most samples receiving the highest or next highest performance grade. The spun-dyed fibres also hold great potential to be recycled themselves without colour change or loss in colour intensity. Textiles with colours produced in large quantities such as black or navy blue could be the first market entry point.

Modifying Polymer-Based Hard Carbons for Enhanced Understanding of Sodium Storage Properties

Numerous theories on the storage of sodium in hard carbons can be found in the literature. In particular, understanding the contributions of (heteroatom) doping, porosity and graphitic layers is of great importance. Much of the current literature on hard carbons uses different biomaterials as precursors in order to improve the sustainability of the synthesis. However, large differences in the composition of the starting materials and the presence of foreign atoms make a systematic investigation of the storage process extremely difficult.Therefore, a hard carbon material based on furan resins was used in this work to obtain a well-defined starting material that can be modified systematically. This allows a detailed investigation of the effects caused by those modifications. Modifications can be achieved by directly adding various template materials to the polymerization process. Both doping with heteroatoms by adding template chemicals such as boric acid and the introduction of graphitic layers by adding high-purity graphite during polymerization were investigated.Addition of boron and phosphorus heteroatoms led to an increase in reversible capacity up to 240 mAh g-1 from 150 mAh g-1 for carbonization temperatures as low as 650°C. Formation of a potential plateau was observed for boron doping, which is usually found at higher carbonization temperature surpassing 1000°C. Utilizing Raman and XRD spectroscopy, crystallite size was found to be decreasing with phosphorus doping, while boron doping led to an increase. This increase could be a possible explanation for the observed capacity plateau.The addition of high-purity carbon samples, such as KS6L graphite or graphene, allowed for a targeted introduction of single- and multi-layer graphitic domains without alteration of additional properties. Increasing graphite content up to 5 wt-% during polymerization resulted in enhanced electrochemical characteristics, including increased sodium intercalation into the lattice and shift of the sloping proportion to lower potentials. Further increase up to 10 wt-% led to a vanishing of the plateau potential and a lowering of the reversible capacity. The results indicate that the interlayer spacings has now decreased below a threshold, which prohibits the sodium from intercalation between the graphitic layers. Additionally, doping Hard Carbons with graphene revealed a capacity decrease at content ratios as low as 2 wt-%, emphasizing the significance of both the stacking and interlayer spacing of the graphitic lattice, as well as the chemical composition, for efficient sodium storage.In summary the results presented provide an enhanced understanding into the sodium storage properties of Hard Carbons, which help improve the design of synthesis processes for more cost-efficient and high-performance carbon materials. Figure 1

Azobenzene-containing ionic metathesis copolymers: Composition, self-assembly and photoresponsive property

The properties of synthetic polymers are influenced by the connection mode of polymer chains even polymers made from the same monomer. In this work, the diverse composition systems of cyclooctene-based alternating, random and block azo-copolymers containing imidazolium cation units as side group were successfully achieved based on different metathesis methods in the ionic liquid with good control over the polymerization processes. All these ionic azo-copolymers were tailored to explore the effects of monomers sequences and non-covalent interactions on photoresponsive behaviors and self-assembly morphologies. Since the special alternating structure, UV-light-triggered the shackling trans→cis photoisomerization transition was observed, ultimately spontaneously forming highly regular and uniform polymer vesicle with recoverable size variation in THF directly. Differently, the micellar characterization was carried out by the self-assembly of ionic block azo-copolymers in a selective solvent of toluene to obtain spherical micelle with reversible shape evolution considering nearly 86 % trans→cis relative isomerization efficiency. These interesting results not only demonstrate the diversity of metathesis polymerization but also expand the property of azo-copolymers.

Compositional Characterization of Syngas-Based Glycolide Using Gas Chromatogram-Mass Spectrometry and Electrospray Ionization High-Resolution Mass Spectrometry.

Polyglycolic acid (PGA) is a biologically friendly material with a wide range of applications. The production of dimethyl oxalate using coal-based syngas and the hydrogenation of dimethyl oxalate can produce the polymerization raw material of PGA, glycolide, which requires a methyl glycolate polymerization and depolymerization process. The intermediate products of the production process were analyzed using gas chromatogram-mass spectrometry (GC-MS) and Orbitrap mass spectrometry (Orbitrap MS), which revealed the presence of cyclic and linear PGAs with different capped ends. The impurities present in the oligomer were mostly methyl-capped PGA and were retained in the subsequent depolymerization process to glycolide, solvent washing can be used to remove this part of the impurity and ultimately obtain a refined glycolide product. Furthermore, it is proposed that the use of the specialized Kendrick Mass Defect (KMD) to plot and analyze PGA compounds obtained using mass spectrometry can enable the direct classification of PGAs without the need for exact molecular formula assignment.

Construction of low-resistance nano-transport channels with UiO-66-(NH2)2 “transmembrane” in polyamide layer structure for efficient nanofiltration

Metal-organic frameworks (MOFs) is always a research hotspot as the modifier for fabrication of thin-film nanocomposite (TFN) membrane due to their excellent chemical tunability and suitable pore size. However, the traditional strategy for the involvement of MOFs into interfacial polymerization (IP) process has its limitations, as the addition of MOFs only serve to modulate the structure of the polyamide (PA) layer and to optimize the transport path of water molecules, rather than play an important role in selectively sieving solutes. To solve the problem that MOF embedded under the PA layer cannot directly participate in solute sieving, this study designed a “transmembrane” structure of MOF in the PA layer. Here, the feasibility of 1,3,5-Benzenetricarbonyl chloride modified UiO-66-(NH2)2 was verified based on Gibbs free energy calculations. By adding chlorinated UiO-66-(NH2)2 nanomaterials in the dual IP process, a high-throughput nanofiltration membrane was innovatively constructed. In contrast to conventional thin-film composite membrane prepared by only one IP process, the sieving mechanism no longer relied solely on the free volume of the PA chain segments. Instead, it was determined by the combination of the pore channels of UiO-66-(NH2)2 and the matrix gaps. Based on density functional theory (DFT), the calculated diffusion energy barriers of H2O and Na2SO4 in UiO-66-(NH2)2 and PA matrices reveal the reasons for the improvement of water flux and changes in retention rate of TFN membranes. In addition, the gap size between PA-MOFs was determined by comparing the solvation and de-solvation structures of dye molecules. This work provides a new theoretical basis for explaining the changes in the separation performance of TFN membranes, and offers new ideas for the development of novel TFN membrane structures.

Fabrication, optimization, and in vitro validation of penicillin-loaded hydrogels for controlled drug delivery

Bacterial infections present a major global challenge. Penicillin, a widely used antibiotic known for its effectiveness and safety, is frequently prescribed. However, its short half-life necessitates multiple high-dose daily administrations, leading to severe side-effects. Therefore, this study aims to address these issues by developing hydrogels which control the release of penicillin and alleviate its adverse effects. Various combinations of aspartic acid and acrylamide were crosslinked by N′, N′-methylene bisacrylamide through a free radical polymerization process to prepare aspartic acid/acrylamide (Asp/Am) hydrogels. The fabricated hydrogels underwent comprehensive characterization to assess physical properties and thermal stability. The soluble and insoluble fractions and porosity of the synthesized matrix were evaluated by sol-gel and porosity studies. Gel fraction was estimated at 88–96%, whereas sol fraction was found 12–4% and porosity found within the 63–78% range for fabricated hydrogel formulations. Maximum swelling and drug release were seen at pH 7.4, demonstrating a controlled drug release from hydrogel networks. The results showed that swelling, porosity, gel fraction, and drug release increased with higher concentrations of aspartic acid and acrylamide. However, integration of N′, N′-methylene bisacrylamide exhibited the opposite effect on swelling and porosity, while increasing gel fraction. All formulations followed the Korsymer–Peppas model of kinetics with ‘r’ values within the range of 0.9740–0.9980. Furthermore, the cytotoxicity study indicated an effective and safe use of hydrogel because the cell viability was higher than 70%. Therefore, these prepared hydrogels show promise candidates for controlled release of Penicillin and are anticipated to be valuable in clinical applications.

Triple network hydrogel-based structure triboelectric nanogenerator for human motion detection and structural health monitoring

In this study, we developed a high-performance triple network (TN) PVA/PAAM/PEDOT/Zn2+ (PMPZ) hydrogel with exceptional mechanical properties and stable output performance. The robust and highly tough TN structure, fabricated via a Zn2+ pinned hydrogel and multi-network interpenetrating polymerization process, demonstrates high mechanical strength alongside exceptional mechanical properties. The PMPZ hydrogels exhibit notable mechanical sensing capabilities (gauge factor: 48.6) while maintaining excellent tensile (83.79 KPa) and compressive (96 MPa) strengths. As a triboelectric nanogenerator (TENG), the PMPZ-TENG shows outstanding flexibility and integrability, achieving a maximum open-circuit voltage (Voc) of 326.89 V and a peak power density of 368.3 μW/cm² with a load resistance of 10E8 Ω. Furthermore, the PMPZ-TENG demonstrates enduring practicality and responsiveness as a self-powered sensor. These properties make the PMPZ-TENG highly suitable for applications in human health monitoring. Additionally, we conducted computational simulations on the hydrogel and seismic-resistant civil models. 48 prototype structures simulated different seismic hazard levels to effectively capture plastic hinge deformation within high-strength steel composite K-shaped eccentric braced steel frames. The plastic hinge deformations informed the establishment of physical seismic models for structural health monitoring (SHM). This study not only introduces a high-performance PMPZ-TENG meeting practical requirements but also establishes a novel pathway for integrating TENGs in SHM.

Ether chain modified electrochromic polymer based on EDOT and benzene

Polar side chain plays an critical role in regulating molecular aggregation, film morphology and electrochromic properties of conjugated polymer. Here an ether chain modified conjugated polymer poly(EB-ether) based on EDOT and benzene was prepared at low oxidation potential by electrochemical method in EtOH-CH2Cl2 (v/v = 5/1) containing 0.1 M Bu4NPF6. The prepared poly(EB-ether) could achieve similar electrochromic parameters with alkoxy chain modified poly(EB-alkoxy), such as optical contrast of 35 %, response time of 0.8 s, coloration efficiency of 283 C−1 cm2, and reversible color change between dark red and blue. Electrochromic results indicate that high-performance poly(EB-ether) film could be prepared in mixed solvent containing little CH2Cl2. Therefore, the introduction of ether chain in precursor is a feasible method to decrease or avoid the use of halogenated solvent in electrochemical polymerization process of precursor.

A facile solvent activation process manipulates the structure and filtration performance of oxidized poly (arylene sulfide sulfone) TFC membrane

In this study, solvent-resistant polyamide (PA) thin film composite (TFC) nanofiltration (NF) membranes were successfully prepared based on an ultrasolvent-resistant oxidized poly (arylene sulfide sulfone) (O-PASS) substrate. The effects of different substrates on interfacial polymerization (IP) process were systematically studied. The O-PASS-TFC membranes were activated to different degrees by a controlled activation process using the mixture solvent of DMF/H2O with different ratio of DMF, the solubility power can be designed by adjusting DMF volume fraction, as the activation solvent. The membrane followed pure DMF treatment was found to have the excellent performance: the surface morphology of TFC membrane was activated to smooth and high negative charged, yield nanofiltration (NF) performance with a solution permeance of 8.82 LMH bar−1 (~621 % increase) and a pure water permeance (PWP) of 11.59 LMH bar−1 (~607 % increase), Na2SO4 rejection maintained above 98.7 %. On the other hands, the same O-PASS-TFC membrane activated with solvent mixture volume ratio of DMF/H2O = 0.5 exhibited enhanced Na2SO4 rejection of 99 %, with greater solution permeance of 3.01 LMH bar−1 (~212 % increase). The correlations between the different activation treatment-membrane structure-separation properties of O-PASS-TFC membranes with different solvent activation degrees were investigated in detail. In this work, the ultrasolvent-resistant property of O-PASS substrate was combined to regulate its TFC membrane structure, and then further to endow the TFC membrane with multiple excellent filtration performance by fully utilizing the solvent activation effect of DMF. Through this strategy, it supplies a facile and promising route for preparation of high efficiency TFC membrane.

One-Pot Preparation of Ratiometric Fluorescent Molecularly Imprinted Polymer Nanosensor for Sensitive and Selective Detection of 2,4-Dichlorophenoxyacetic Acid.

The development of fluorescent molecular imprinting sensors for direct, rapid, and sensitive detection of small organic molecules in aqueous systems has always presented a significant challenge in the field of detection. In this study, we successfully prepared a hydrophilic colloidal molecular imprinted polymer (MIP) with 2,4-dichlorophenoxyacetic acid (2,4-D) using a one-pot approach that incorporated polyglycerol methacrylate (PGMMA-TTC), a hydrophilic macromolecular chain transfer agent, to mediate reversible addition-fragmentation chain transfer precipitation polymerization (RAFTPP). To simplify the polymerization process while achieving ratiometric fluorescence detection, red fluorescent CdTe quantum dots (QDs) and green fluorescent nitrobenzodiazole (NBD) were introduced as fluorophores (with NBD serving as an enhancer to the template and QDs being inert). This strategy effectively eliminated background noise and significantly improved detection accuracy. Uniform-sized MIP microspheres with high surface hydrophilicity and incorporated ratiometric fluorescent labels were successfully synthesized. In aqueous systems, the hydrophilic ratio fluorescent MIP exhibited a linear response range from 0 to 25 μM for the template molecule 2,4-D with a detection limit of 0.13 μM. These results demonstrate that the ratiometric fluorescent MIP possesses excellent recognition characteristics and selectivity towards 2,4-D, thus, making it suitable for selective detection of trace amounts of pesticide 2,4-D in aqueous systems.