Search Results (113)

This study utilizes QM/MM Born–Oppenheimer Molecular Dynamics in order to model the process of intermolecular binding between reduced graphene oxide (rGO) and butadiene–acrylonitrile copolymer (PBDAN) with a monomer ratio of 2:1. This research aims to elucidate the structural reasons behind the enhancing properties of the substrate, focusing on the polymer matrix. The behavior of each phase was examined and discussed. More importantly, the intermolecular interactions within the interphase zone of adsorption were investigated on an atomic scale. We found and characterized 58 such instances, grouped into hydrogen bonds and three types of stacking: π–π, σ–π, and σ–n. Each occurrence was analyzed through the use of radial distribution functions. Five spontaneous chemical processes within the rGO nanoparticle were modeled and characterized. Two of them were found to provide stabilization only within the substrate, while the rest are relevant for the overall constitution of the heteromaterial. Perhaps most intriguing is the process of self-repair as part of the vacancy defect. This occurs entirely within the carbon frame of the rGO layer. We believe our results to be of importance for a large set of ligand materials, mostly those which contain unsaturated bonds and electronegative atoms. Full article

Multi-acceptor and all-acceptor polymers solve the fundamental challenge of achieving unipolar electron transport without compromising stability in n-type polymer field-effect transistors. By systematically replacing electron-rich donors with acceptor units, these architectures push LUMO levels below −4.0 eV and HOMO levels below −5.7 eV. Consequently, electron mobilities exceeding 7 cm² V⁻¹ s⁻¹, on/off ratios approaching 10⁷, and months-long ambient operation can be achieved. This review connects the molecular architecture to device function. We assert that short-range π-aggregation matters more than crystallinity—tight π-stacking over 5–10 molecules drives transport in rigid backbones. Device optimization through interface engineering (e.g., amine-functionalized self-assembled monolayers reduce the threshold voltages to 1–5 V), contact resistance minimization, and controlled processing transform the intrinsic material potential into working transistors. Current challenges, such as balancing the operating voltage against stability, scaling synthetic yields, and reducing contact resistance, define near-term research directions toward complementary circuits, thermoelectrics, and bioelectronics. Full article

Organic field-effect transistors (OFETs) require reliable micro- and nanoscale patterning of semiconducting layers, yet conjugated polymers have long been considered incompatible with photolithography due to dissolution and chemical damage from photoresist solvents. Here, we present a photolithography-compatible strategy based on doping-induced solubility conversion (DISC), demonstrated using poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT). AuCl₃ doping reversibly modulates the benzoid/quinoid resonance balance, lamellar stacking, and π–π interactions, suppressing solubility during lithographic exposure, while dedoping restores the intrinsic electronic properties. Using this approach, micropatterns with linewidths as small as 2 µm were fabricated in diverse geometries—including line arrays, concentric rings, dot arrays, and curved channels—with high fidelity; quantitative analysis of dot arrays yielded mean absolute errors of 48–66 nm and coefficients of variation of 2.0–3.9%, confirming resolution and reproducibility across large areas. Importantly, OFETs based on patterned PBTTT exhibited charge-carrier mobility, threshold voltage, and on/off ratios comparable to spin-coated devices, despite undergoing multiple photolithography steps, indicating preservation of transport characteristics. Furthermore, the same DISC-assisted lithography was successfully applied to other representative p-type conjugated polymers, including P3HT and PDPP-4T, confirming the universality of the method. This scalable strategy thus combines the precision of established lithography with the functional advantages of organic semiconductors, providing a robust platform for high-density organic electronic integration in flexible circuits, biointerfaces, and active-matrix systems. Full article

Tailoring the spin crossover (SCO) effect in molecular materials remains a fundamental challenge, driven by the need to control critical parameters, such as the spin transition temperature (T₁/₂), hysteresis width, cooperativity, and switching kinetics for applications in sensing, memory, and actuation devices. SCO behavior is highly sensitive to small changes in the structure or crystal structure of the surrounding environment. In this context, achieving predictable and reproducible control remains elusive. Embedding SCO complexes into polymer matrices offers a more versatile and processable approach, but understanding how matrix–guest interactions affect spin-state behavior is still limited. In this study, we investigate a polymer-mediated strategy to tune SCO properties by incorporating the well-characterized Fe(II) complex [Fe(1,10-phenanthroline)₂(NCS)₂] into three polymers with distinct structural features: polylactic acid (PLA), polystyrene (PS), and polysulfone (PSF). In terms of potential electrostatic interaction between the complex and the polymeric matrixes, the polymers offer distinct features. Either there does not seem to be any specific interaction (PLA case) or, rather, there is π-π stacking between the aromatic rings of the SCO complex, and the corresponding ones present either in the backbone or in the side chain of the polymer (PSF and PS, respectively). The latter can potentially influence spin-state energetics and dynamics. Importantly, we also reveal and quantify the migration behavior of SCO particles within different polymer matrices, an aspect that has not been previously examined in SCO–polymer systems. Using magnetic susceptibility, spectroscopic, diffraction, and migration studies, we show that the polymer environment, PLA as well, actively modulates the SCO response. PSF yields lower T₁/₂, slower switching kinetics, and enhanced retention of the complex, indicative of strong matrix confinement and interaction. In contrast, PLA and PS composites exhibit sharper transitions and higher migration, suggesting weaker interactions and greater mobility. In addition, the semi-crystalline nature of PLA seems to induce the extension of the hysteresis width. These results highlight both the challenge and the opportunity in SCO polymer composites to tune SCO behavior, offering a scalable route toward functional hybrid materials for thermal sensing and responsive devices. Full article

Microplastics (MPs) and nanoplastics (NPs) are emerging aquatic contaminants that pose environmental and public health risks due to their persistence, ubiquity, and ability to adsorb co-contaminants. This scoping review synthesises findings from 57 experimental studies and five review studies published between 2019 and 2025 on the use of biochar-based materials for the removal of microplastics from water and wastewater. Guided by the hypothesis that surface-modified biochars, such as magnetised, surfactant-coated, or chemically activated forms, achieve high removal efficiencies through multimodal mechanisms (e.g., electrostatic attraction, hydrophobic interactions, π–π stacking, and physical entrapment), this review applies PRISMA-based protocols to systematically evaluate biochar feedstocks, pyrolysis conditions, surface modifications, polymer types, removal mechanisms, and regeneration approaches. Scopus, Web of Science, and PubMed were searched until 30 May 2025 (English-only), and 62 studies were included. The review was not registered, and no protocol was prepared. The results confirm a high removal efficiency (>90%) in most experimental studies, particularly under controlled laboratory conditions and using pristine polystyrene. However, the performance declines significantly in complex matrices (e.g., wastewater and surface water) owing to dissolved organic matter, ionic competition, and particle heterogeneity, thus supporting the guiding hypothesis. This review also identifies critical methodological gaps, including narrow plastic typologies, a lack of standardised testing protocols, and limited field-scale validation. Addressing these gaps through environmentally realistic testing, regeneration optimisation, and harmonised methods is essential for transitioning biochar from a promising sorbent to a practical water treatment solution. Full article

Background/Objectives: Surfactants are commonly used in amorphous solid dispersions (ASDs) to improve drug dissolution. A mechanistic understanding of their impact on in vitro dissolution and in vivo pharmacokinetics is essential for rational ASD design and for establishing predictive in vitro–in vivo correlation (IVIVC). Methods: Binary (Cur/P188) and ternary (Cur/P188/TW80, Cur/P188/SLS) ASDs were prepared by rotary evaporation. Drug–polymer–surfactant interactions were characterized by ¹H NMR and FT-IR spectroscopy. To elucidate the bioavailability enhancement mechanism, we performed (i) in vitro non-sink dissolution to assess dissolution kinetics, nanostructure formation, and precipitate transformation; (ii) cellular uptake assays; and (iii) in vivo pharmacokinetic studies. Results: Cur self-associates via hydrogen bonding and π-π stacking, limiting its solubility. Polymer carrier P188 disrupts these interactions and forms stronger drug–polymer bonding. Surfactants TW80 and SLS exhibited distinct interaction profiles: TW80 competitively disrupted Cur-P188 bonding, whereas SLS integrated into the Cur-P188 assembly to form stable ternary nanostructures. The Cur/P188/SLS ASD achieved the highest and most sustained supersaturation, maintained amorphous precipitates, and enhanced cellular uptake, leading to significantly improved oral bioavailability. Conclusions: Surfactants critically influence ASD performance by preserving high-energy drug states through three key mechanisms: (1) generating and maintaining supersaturation, (2) facilitating nanostructure formation, and (3) stabilizing amorphous precipitates. These mechanisms collectively enhance cellular uptake and bioavailability. Our findings demonstrate that both dissolution and in vivo performance are governed by multifaceted drug–polymer–surfactant interactions, providing critical insights into surfactant functionality and IVIVC to guide rational ASD formulation. Full article

Oil sands drilling frequently contaminates water-based xanthan gels with highly viscous asphaltenes, collapsing their three-dimensional network and causing barite sag, high fluid loss and poor cuttings transport. Nitrogen-functionalized carbon quantum dots (N-CQDs) were hydrothermally synthesised from citric acid and 1-hexadecylamine and characterised by means of FT-IR, TEM and TGA. The concentration-dependent influence of N-CQDs (0–1.2 wt%) on gel viscoelasticity, microstructure and filtration properties was evaluated through rheometry, API and fluid-loss tests. At 0.01 wt% N-CQDs, the viscosity of the adsorbed oil phase dropped by 50% and the mean droplet diameter decreased from 247.7 µm to <100 µm. Consequently, the xanthan gel exhibited a significant enhancement in its mechanical strength and fluid loss performance. Wax-crystal growth was simultaneously inhibited, lowering the pour point by 6 °C. N-CQDs act as nanospacers that disrupt π-stacking of asphaltenes and hydrogen-bond to the polymer backbone, thereby restoring gel strength and sealing capacity. The work provides a sustainable, low-toxicity route to rejuvenate gel-based drilling fluids contaminated by heavy oil and facilitates their reuse in oil sands reservoirs. Full article

The reaction of 4,4′-bipyridine (C₁₀H₈N₂) with the alkali metal pentacyanocyclopentadienides [Na{C₅(CN)₅}(MeOH)] and [KC₅(CN)₅] gives the coordination polymers [Na{C₅(CN)₅}(EtOH)(H₂O)(C₁₀H₈N₂)] (1) and [K{C₅(CN)₅}(H₂O)₂] • 2 (C₁₀H₈N₂) (2) after recrystallization from EtOH. Both compounds show octahedral coordination around the metal ion with a NaN₄O₂ and KN₂O₄ environment. The [C₅(CN)₅] acts as a 1,1-bridging ligand in 1 and a 1,2-bridging ligand in 2. The 4,4′-bipyridine acts as a N,N′-bridging ligand between dimeric [Na₂(EtOH)₂(H₂O)₂(µ-{C₅(CN)₅}₂] units, while it acts only as a guest molecule in the voids between polymeric [K(µ-H₂O)_4/2{µ-C₅(CN)₅}_2/2]_∞ chains. Both compounds employ multiple hydrogen bonds and π stacking to stabilize the crystalline structures. Full article

The mechanism of separating the small chiral drug molecules on large soft polymers is essential in pharmaceutical science. As a case study, the differentiation mechanism of ibuprofen, (R,S)-2-(4-isobutylphenyl)propanoic acid, with cellulose tris(4-methylbenzoate) (CMB) as the chiral stationary phase (CSP) was investigated by combining the molecular docking simulation and multi-level layered terminal-to-center elongation (ML-T2C-ELG) method. Our results demonstrated that, based on the optimized geometry using the ML-T2C-ELG method, the complexation energy of S-ibuprofen with CMB obtained at B3LYP-D3(BJ)/6-311G(d) level is more negative than that of R-ibuprofen, which is caused by the greater hydrogen bonding and π-π stacking interactions between CMB and S-ibuprofen. The results are in line with the experimental observations of high-performance liquid chromatography (HPLC) that the retention time of S-ibuprofen on CMB is longer than that of R-ibuprofen. Moreover, the ML-T2C-ELG method was found to be valuable for optimizing the geometries of such flexible and large systems, which allows for a more accurate description of interactions between soft polymers and small molecules when coupled with the docking simulation. It is anticipated that this study can provide beneficial insights for future optical resolution mechanisms of other chiral drugs. Full article

Polypyrrole, which belongs to the conducting polymer family, has demonstrated profound potential in advanced water purification applications due to its inherent electrical conductivity, environmental stability, and tunable surface chemistry. As a sorbent, PPy exhibits high sorption capacity for aquatic contaminants, including heavy metals, pharmaceutical compounds, and their metabolites, as well as synthetic dyes. The removal efficiency is correlated to a complex interaction mechanism involving electrostatic attractions, redox activity, and π–π stacking. Recent advances have expanded the utility by further developing nanostructured PPy-based (nano)composites, which elevate sorption performance by increasing surface area, mechanical integrity, and selective affinity. In addition, its integration into membrane technologies has enabled the design of an effective filtration system with improved selectivity and regeneration capabilities. Moreover, PPy is effective in electrochemical processes of water treatment, including capacitive deionization and electrochemically assisted sorption, opening novel paths towards energy-efficient pollutant removal. The multifunctionality of PPy as a sorbent material highlights its value as an important material for water treatment, with the capability of extended modification tailored for emerging environmental needs revised in this work. Full article

This study investigates the adsorption behavior of 4-methylbenzylidene camphor (4-MBC), a persistent ultraviolet filter, onto microplastic fibers (MPFs) released from domestic textiles, under environmentally relevant conditions. Two types of MPFs were used: MPF A, a heterogeneous blend of synthetic and natural fibers, and MPF B, a uniform polyester source. Adsorption experiments were conducted in municipal wastewater, Danube River surface water, and laundry effluent. Kinetic data best fit the pseudo-second-order model (R² > 0.95), and the Elovich model indicated chemisorption involving heterogeneous binding sites. MPF A exhibited superior adsorption capacities (qₑ = 85.4–90.1 µg/g) compared to MPF B (58.8–66.8 µg/g). Langmuir isotherms yielded maximum adsorption capacities of 204.9 µg/g for MPF A and 116.7 µg/g for MPF B (R² = 0.929–0.977), while D–R isotherm energies (12.0–21.7 kJ/mol) confirmed specific interactions, such as π–π stacking and hydrogen bonding. Adsorption efficiency was highest in municipal wastewater (total organic carbon—TOC = 13.12 mg/L, electrical conductivity—EC = 1152 µS/cm), followed by laundry and surface waters. These findings emphasize the critical role of polymer composition and matrix complexity in pollutant transport, suggesting MPFs are effective transporters of hydrophobic micropollutants in aquatic systems. Full article

Micron-sized, ultrathin metal–organic framework (MOF) sheet is a two-dimensional (2D) hybrid material with a large specific surface area, which can be used not only in the fields of energy and biomedicine, but also in electrode modification to improve the electrochemical detection effect. In this work, the 2D-structured Co-TCPP(Fe) MOF sheets were synthesized from porphyrin molecules and cobalt ions and then combined with reduced graphene oxide (rGO) and perfluorosulfonic acid polymer (Nafion) solution to construct Co-TCPP(Fe)/rGO/Nafion-modified electrodes capable of sensitively capturing dopamine (DA). The 2D ultrathin lamellar structure of this electrode-modified material is beneficial to the formation of π-π stacking effect with DA molecules, and the oxygen-containing groups carried on its surface can also form electrostatic attraction with the amino groups of DA molecules. Therefore, the Co-TCPP(Fe)/rGO/Nafion-modified electrode under the synergistic effect shows a specific adsorption effect on DA molecules, resulting in high anti-interference ability and a low detection limit of 0.014 µM in the concentration range of 0.1–100 µM. Furthermore, the Co-TCPP(Fe)/rGO/Nafion composite material composed of micron-sized, ultrathin lamellar structures also shows high reusability due to the stability of its coordination structure and can demonstrate good results when applied to the actual sample detection of human urine. Full article

Naproxen sodium is an emerging pollutant that may pose potential hazards to human health and the ecological environment. However, developing highly effective adsorbents for the extraction of naproxen sodium from aqueous environments is still a challenge. Herein, we have prepared a novel amino-functional ionic liquid polymer adsorbent (NH₂-IL-PS) for the extraction of naproxen sodium (NPS) from aqueous environments. It was found that the NH₂-IL-PS exhibits a high adsorption capacity of 456.6 mg/g for NPS and maintains high extraction efficiency over a wide pH range of 4 to 9 at room temperature. Notably, even when the concentration of NPS was lower than 5 ppb, the extraction efficiency still exceeded 90.0%, with the enrichment factor reaching up to 600.0. More importantly, the NH₂-IL-PS adsorbent material can withstand at least 16 consecutive adsorption cycles while maintaining an extraction efficiency of over 90.0%. Finally, the NH₂-IL-PS was successfully applied to extract and determine NPS in seven types of real water samples, with relative recoveries ranging from 90.9 to 96.2%. The study of the adsorption mechanism reveals that electrostatic interactions, ion exchange, π-π stacking, and hydrogen bonding are crucial in the extraction of NPS. This study provides a sustainable strategy for the efficient extraction of NPS. Full article

The reaction of copper nitrate, phthalic acid (1,2-H₂BDC), and bipyridine in ammonia/ethanol media affords two multi-copper (II) cluster-based coordination polymers, namely {[Cu₄(bpy)₄(OH)₂(BDC)₂]·2OH·13H₂O}_n (USC-CP-6) and {[Cu₂(BDC)₂(bpy)₂(H₂O)]·3H₂O}_n (USC-CP-7), under ambient conditions, with CP-6 forming at the bottom and CP-7 at the upper edge of the same beaker. The single-crystal structures reveal that it is a rare case of gradient-induced formation of different multi-copper(II) cluster-based CPs within a single-solution chemical reaction. CP-6 crystallizes in the monoclinic system, sp. gr. P2₁/c, and is composed of chair-like tetranuclear [Cu₄(μ₃-OH)₂(bpy)₄(BDC)₂]²⁺ clusters as secondary building units, bridged by BDC²⁻ ligands to form a two-dimensional layer framework, while CP-7 crystallizes in the monoclinic system, sp. gr. P2₁/n, with binuclear [Cu₂(1,2-BDC)₂(bpy)₂(H₂O)] clusters linked by bridging BDC²⁻ ligands to form a one-dimensional looped double chain. Through intermolecular π–π stacking and hydrogen bonds between the coordination water, lattice water, and free oxygen atoms from carboxylate, both compounds yield a 3D supramolecular structure. Full article

Two new Co(II) coordination compounds viz. [Co(H₂O)(bz)₂(μ-3-Ampy)₂]_n (1) and [Co(4-Mebz)₂(2-Ampy)₂] (2) (wherebz = benzoate, 4-Mebz = 4-Methylbenzoate and Ampy = Aminopyridine) were synthesized and characterized via elemental (CHN), electronic spectroscopy, FT-IR spectroscopy, and thermogravimetric analysis (TGA). The molecular structures were determined by single-crystal X-ray diffraction analysis, inferring that compound 1 crystallizes as a 3-Ampy bridged Co(II) coordination polymer, whereas compound 2 crystallizes as a mononuclear Co(II) compound. Compound 1 unfolds the presence of N–H⋯O, C–H⋯O, O–H⋯O, C–H⋯N and aromatic π⋯π interactions, while for compound 2, N–H⋯O, C–H⋯O, C–H⋯C and C–H⋯π interactions are observed. Both the compounds showcase scarcely reported chelate ring interactions involving the benzoate moiety (chelate ring⋯π in 1 and N–H⋯chelate ring in 2). We also conducted theoretical evaluations comprising of combined QTAIM/NCI plot analysis, DFT energy calculation and MEP surface analysis to analyze the supramolecular interactions present in the crystal structures. As per QTAIM parameters, the predominance of π-stacking interactions over hydrogen bonds in stabilizing the assembly in compound 1 is affirmed. Likewise, in compound 2, both hydrogen bonding (HBs) and C–H⋯π interactions are deemed pivotal in stabilizing the dimeric assemblies. The in vitro antiproliferative activities of compounds 1 and 2 were performed against Dalton’s lymphoma (DL) cancer cell lines through cytotoxicity and apoptosis assays, showcasing higher cytotoxicity of compound 1 (IC₅₀ = 28 μM) over compound 2 (IC₅₀ = 34 μM). Additionally, a molecular docking study investigated the structure–activity relationship of these compounds and allowed an understanding of the molecular behaviour after treatment. Full article