Amphiphilic cylindrical brushes consisting of a cellulose backbone and grafted poly(methacrylic acid) chains (Cell-g-PMAA) with high grafting density were synthesized. Their interaction with europium ions in dilute aqueous solutions (0.002–0.02 wt%) was investigated. A comparative study of photophysical properties of (europium-phenanthroline) complexes with Cell-g-PMAA and (europium-phenanthroline) complexes with linear poly(methacrylic acid) was carried out. It was found that the intensity of Eu 3+ luminescence in the complexes with Cell-g-PMAA is an order of magnitude higher than the corresponding value for europium complexes with linear PMAA. It is suggested that solubilization of phenanthroline in the hydrophobic part of the brush (i.e., in the layer between the main chain and grafted chains) enhances its Eu 3+ binding efficiency, which, in turn, leads to the replacement of water molecules in the inner coordination sphere with phenanthroline molecules. In addition, the decrease in the mobility of grafted chain segments near the backbone “strengthens” the structure of the complex. The obtained results indicate that structural organization of a macromolecular ligand plays a significant role in the formation of europium ion complexes and contributes to the enhancement of photoluminescence.

The development of polymeric materials that exhibit blue thermally activated delayed fluorescence (TADF)0 is of great interest for optoelectronic applications. However, achieving TADF in polymers often requires an elaborate monomer design. The high-energy local triplet state (3LE) of carbazole complicates its application despite the molecular orbital arrangement being suitable for blue emission. Here, we present an approach to polymer design that makes it possible to solve this problem. We demonstrate the in situ formation of a TADF donor-acceptor system during Suzuki polycondensation, creating an extended carbazole-based donor matrix coupled00 with a triazine acceptor. The resulting polymer exhibited efficient TADF with a low energy gap (ΔEST) value if a phenyl N-substituent, enabling essential electron delocalization, was present in the carbazole moiety. This work establishes a versatile platform for developing carbazole-based TADF polymers, overcoming the fundamental limitations that hinder their widespread application.

Hybrid systems comprising TADF materials and inorganic emitters, such as semiconductor quantum dots and perovskite nanostructures, are utilized in light-emitting diodes.

An efficient, simple, and convenient method for Suzuki polycondensation using a diaminocarbene palladium(II) catalyst under aerobic conditions was developed. Reactions between aromatic diboronic acid bis(pinacol) ester and different aromatic dibromides, both with electron-donating and electron-withdrawing fragments in the structure, were carried out. Various reaction conditions, such as the effect of catalyst concentration and solvent, were investigated. The molecular weight characteristics, photo- and electroluminescence properties of the synthesized polymers were studied.

In this work, the interaction of the closo-decaborate anion with a series of substituted dicyanostilbenes was studied. A range of new derivatives of the composition [B10H9R]–, where R is a phenanthrenedicyan substituent with substituents at positions 1 and 10, was obtained. Optimal reaction conditions were selected. To increase the stability of the target compounds, amidine derivatives were synthesized by reacting the obtained nitrile derivatives of the closo-decaborate anion with ammonia in an aqueous-alcoholic medium. The composition and structure of the obtained compounds were determined using multinuclear NMR spectroscopy, mass spectrometry, and IR spectroscopy.

Carbon dots (CDs) are fluorescent carbon nanomaterials that are considered for applications in optoelectronics, sensorics, and biofields due to their low‐cost and robust synthesis, and versatile optical properties. Herein, it is demonstrated how chemical functionalization of hydrophilic or amphiphilic CDs with polyethylene glycol influences their energy level structure and hence the emission properties. Functionalization of CDs with polyethylene glycol results in an increase in emission quantum yield: from 30% to 75% for hydrophilic CDs and from 20% to 25% for amphiphilic CDs. The estimated absolute values of energy levels, including the highest occupied molecular orbital and the lowest unoccupied molecular orbital energies, are dependent on chemical composition and size of CDs. Moreover, polyethylene glycol‐functionalized CD can form good quality films based on their composite with polyvinylcarbazole (PVK), that together with intense emission is crucial for light‐emitting diode (LED) fabrication. By studying spectral properties of fabricated CD‐LEDs, it is shown that their electroluminescence (EL) originates from mixed energy levels of CD and PVK in the composite, resulting in the shifting of the EL maximum from blue to green during several seconds of LED operation. The optimized CD‐LEDs show brightness up to 2600 cd m−2.

Composite hydrogel of cross-linked polyacrylamide (PAAm) containing cellulose-g-poly(methacrylic acid) molecular brushes (MB) as a "soft" filler was prepared by thermoinitiated radical polymerization of acrylamide in the presence of MB. Interaction between linear PAAm and MB results in decrease in PAAm viscosity at high shear rates and increase in storage modulus of mixed solution. Even low amount of MB results in increasing of ultimate compression of PAAm hydrogel, while concentration of MB in semidilute solution regime results in significant increase of hydrogel strength from 2.3 to 6.0 MPa. The use of permeable "soft" filler also allows to preserve high conductivity of hydrogel combined with improved mechanical properties.

The development of advanced wound dressings that integrate favorable physico-mechanical properties with the ability to support physiological healing processes remains a critical challenge in biomaterials science. An ideal dressing should modulate the wound microenvironment, prevent infection, maintain hydration, and possess adequate strength and elasticity. This study aimed to fabricate and characterize electrospun chitosan (CS)-based 3D scaffolds dual-reinforced with halloysite nanotubes (HNTs) and cerium oxide nanoparticles (CeONPs) to enhance material properties and biological performance. HNTs were incorporated to improve electrospinnability and provide mechanical reinforcement, while CeONPs were added for their redox-modulating and anti-inflammatory activities. Composite mats were fabricated via non-capillary electrospinning. The individual and synergistic effects of HNTs and CeONPs were systematically evaluated using physico-chemical methods (SEM, EDX, WAXS, TGA, mechanical testing) and biological assays (in vitro cytocompatibility with mesenchymal stem cells, in vivo biocompatibility, and wound healing efficacy in a rat model). Scaffolds containing only HNTs exhibited defect-free nanofibers with an average diameter of 151 nm, whereas the dual-filler (CS-PEO-HNT-CeONP) composites showed less uniform fibers with a rough surface and a larger average diameter of 233 nm. The dual-filler system demonstrated significantly enhanced mechanical properties, with a Young’s modulus nearly double that of pure CS mats (881 MPa vs. 455 MPa), attributed to strong interfacial interactions. In vivo, the CS-PEO-HNT-CeONP scaffolds degraded more slowly, promoted earlier formation of a connective tissue capsule, and elicited a reduced inflammatory response compared to single-filler systems. Although epithelialization was temporarily delayed, the dual-filler composite ultimately facilitated superior tissue regeneration, characterized by a more organized, native-like collagen architecture. The synergistic combination of HNTs and CeONPs within a CS matrix yields a highly promising scaffold for wound management, offering a unique blend of tailored biodegradability, enhanced mechanical strength, and the ability to guide healing towards a regenerative rather than a fibrotic outcome, particularly for burns and traumatic injuries.

The effect of polyfluorene main chain on both luminescence and pH-sensitivity of polymethine dyes incorporated covalently into the copolyfluorenes was studied. A series of fluorene-polymethine dye copolymers were synthesized by the Suzuki-Miyaura coupling polycondensation using cyanine, keto-cyanine, and squaraine comonomers, which exhibit fluorescence at ca. 500–700 nm. These polymers exhibit both green to red or near-infrared absorption and emission attributed to polymethine dyes, and absorption and emission bands corresponding to polyfluorene (at ca. 380 and 420−470 nm, respectively). The influence of pH on the UV-Vis absorption and luminescence spectra of the copolymers in solution was studied.

The rapid development of thin-film light emitting devices (LED) technologies has recently been associated with the superior optoelectronic properties of luminescent materials based on lead halide perovskite nanocrystals (NCs) due to their narrow emission line with high color purity. However, the large surface area of NCs leads to the need to use solvating ligands to prevent their agglomeration, which limits their use in optoelectronics. Here we develop a class of modular polyfluorene (PF) copolymer with 4-hydroxyphenyl-, diethylamino- and diethoxyphosphoryl- groups designed to stabilize perovskite NCs. We show that as-synthesized CsPbBr3 NCs can easily be mixed with custom-designed PFs resulting in polymer/NCs composite that shows efficient Förster energy transfer (FRET) from PF to NC with green photoluminescence (PL). We also found that the NCs composite studied here can be used as an effective emissive layer in LED due to the strong interaction between polymer host and perovskite NCs providing an efficient charge transfer from the PF matrice to the NC emitter. The fabricated LED show excellent performance with a highest current efficiency of ∼25.2cdA–1. Our approach provides a low-cost and efficient way for light-emitting optoelectronic applications based on perovskite NCs

Amphiphilic molecular brushes or graft copolymers (graft-CPs) with a hydrophobic polyimide main chain and hydrophilic side chains of polymethacrylic acid (PMAA) at high degrees of polymerization m of the side chains and high grafting densities can potentially be used as nanocontainers for targeted delivery of drugs/agents. In the present work, the loaded agent were selenium nanoparticles in the zero-valent form (Se0) possessing a set of unique properties: photoelectric, semiconductor, catalytic, and biomedical properties. A comparative study of free graft copolymers (with a varied degree of polymerization of the hydrophilic PMAA side chains) and graft copolymers loaded with selenium nanoparticles was performed by a wide range of methods (UV/visible spectroscopy, X-ray diffraction analysis, dynamic/electrophoretic light scattering, and atomic force and transmission electron microscopy). The topology of graft-CPs was shown to affect the structural-morphological and spectral characteristics of both free amphiphilic molecular brushes and brushes loaded with selenium nanoparticles.

The structure of previously unknown condensation products of a series of aldoses (N-acetyl-D-glucosamine, D-mannose, D-galactose, and L-fucose) with 4-mercaptobutyric acid hydrazide, promising glyco-ligands of noble metal nanoparticles, has been studied by means of 1H and 13C NMR spectroscopy. It has been shown that the derivatives of N-acetyl-D-glucosamine, D-mannose, and D-galactose exist as a tautomeric mixture of open hydrazone and cyclic pyranose forms in the solution in DMSO-d6. The linear hydrazone form is represented by a set of Z′,E′-conformational isomers, differing in the arrangement of substituents relative to the amide C–N bond, in comparable quantities. The condensation product obtained from L-fucose is an exclusively cyclic pyranose structure in the crystalline state and in solutions in DMSO-d6, represented by a single β-configuration isomer.

A series of molecular brushes with a polyfluorene (PF) backbone and polymethacrylic acid side chains of varying lengths were prepared by atom transfer radical polymerization. The structure and composition of the synthesized compounds were confirmed by 1H NMR and IR spectroscopy. Effect of the length of the backbone on spectral and conformational parameters of the macromolecules in solutions was analyzed. The grafting density of side chains was about 90%. Spectral methods have been used to determine the dependence of side chain grafting on the luminescent properties of polymer solutions, including quantum yields. It was shown that an optimal length of polymethacrylic acid side chains provides solubility of the polymer brushes. Solutions of PF-graft-polymethacrylic acid complexes with the model substance curcumin were investigated. It was established that the molecular brushes containing curcumin form monomolecular micelles. Molecular brushes with zinc phthalocyanine, potential systems for photodynamic, and photothermal therapy, were studied. image

The development of thermally activated delayed fluorescence (TADF) materials with highly efficient reverse intersystem crossing (RISC) processes for organic light-emitting diodes (OLEDs) has received significant attention recently. In this study, we reported two D-A-type TADF emitters, DMAC-Pz1BF2 and DMAC-Pz2BF2, based on isomeric difluoroboron acceptors with similar LUMO energy levels and distinct different locally excited triplet ((LE)-L-3) energy levels. While both emitters had the same energy splitting between their lowest charge-transfer singlet (S-1, (CT)-C-1) and triplet (T-1, (CT)-C-3) states (Delta E-ST = 0.03 eV), DMAC-Pz2BF2 possesses a much smaller S-1 ((CT)-C-1)-T-2 ((LE)-L-3) gap (Delta E((CT)-C-1-(LE)-L-3) = 0.11 eV) compared to that of DMAC-Pz1BF2 (0.38 eV). Consequently, DMAC-Pz2BF2 showed more efficient triplet-to-singlet crossover, along with a larger photoluminescence quantum yield and a higher rate constant of reverse intersystem crossing (k(RISC)) compared to DMAC-Pz1BF2. As expected, the solution-processed OLED device of DMAC-Pz2BF2 exhibited better EL performance with a maximum external quantum efficiency of up to 12.9% and a maximum brightness reaching 21,452 cd/m(2).

The photoluminescence and UV-Vis absorption spectra of copolyamides containing 1,9-anthrazoline with paraand meta-[(substituted carbonyl)amino]phenyl-1-ene moieties in a polymer backbone were studied by a combination of experimental and theoretical approaches. The investigation was accomplished through timedependent density functional theory electronic structure calculations of small-molecule models mimicking a polymer chain. Theoretical absorption and luminescence spectra of ten atomistic models were compared with corresponding experimental data, and the optical properties of two new luminescent molecules with bromine auxochrome were predicted. An analysis of the optical properties demonstrate an identical effect of the type and position of a substituent on the spectra for para- and meta-[(substituted carbonyl)amino]phenyl-1-ene moieties. It was found that the absorption and luminescence spectra of theoretical para-models demonstrate red shifts relative to the corresponding meta-ones. The same phenomenon was observed in experimental spectra of lowmolecular-mass compounds and corresponding copolyamides in solution and bulk. Unique optical properties allow anthrazoline-based polymer compounds to be used in numerous advanced optoelectronic applications with desired optical and electronic characteristics.

Copolyfluorenes have drawn considerable attention owing to their remarkable optoelectronic characteristics, chemical and thermal stability, good film-forming properties, and thus present an active subject of cutting-edge research in the organic electroluminescence. This current systematic review examines and summarizes the latest research on copolyfluorene-based materials for light emitting layers of OLEDs over the past decades.

Copolyfluorenes are of great interest due to their ability to form thin films with tunable optical and electrical properties.In this paper,copolymers of polyfluorene with electron withdrawing dicyanostilbene and dicyanophenanthrene moieties were synthesized;their thin films were characterized by electron spectroscopy,cyclic voltammetry,electrical,and photoelectrical measurements.The mobility of charge carriers in the copolymers was measured for the first time,with the acceptor components providing balanced electron and hole mobilities of the order of 10-6 cm2·V-1·s-1.Photodetectors based on the copolymer/PTCDI heterojunction exhibited the photoresponse band extended into the green re-gion due to the absorption of PTCDI and an increased photocurrent in the UV-blue absorption band of the copolymer,which is related to the ab-sorption of photoluminescent emission of the copolymers in PTCDI.The presented approach to improving the performance of a polymer-based photodetector is promising in organic optoelectronics.

Macromolecules of complex architecture find application as modifiers of commercial polymeric membrane materials. In this work, copolyimide molecular brushes (coPI) composed of polyimide backbone and poly(methacrylic acid) side chains were used to modify poly(m-phenylene iso-phthalamide) (PPA). Structure, physical, mechanical, and transport properties of dense nonporous PPA/coPI membranes containing up to 10 wt% coPI were studied. The effect of included coPI on the membrane structure was estimated using atomic force microscopy and mechanical tests. The coPI modifier contributes to the additional formation of free volume elements evenly distributed throughout the membrane. Transport properties of PPA/coPI membranes were investigated via sorption tests and pervaporation separation of methanol (MeOH) and methyl tert-butyl ether (MTBE) mixtures. The inclusion of coPI modifier in the PPA membrane leads to an increase in the total flux of the membrane. The highest separation factor was found for the PPA/coPI membrane containing 10 wt% coPI; transport properties of the best membrane were compared with the literature data on separation of the azeotropic MeOH-MTBE mixture.

The catalytic activity of C,N-chelate diaminocarbene palladium(II) complexes containing the 3,4-diaryl-1Н-pyrrol-2,5-diimine fragment in the Suzuki reaction was studied. Comparative analysis of the catalytic activity of two types of C,N-chelate diaminocarbene complexes containing in the inner sphere, along with the diaminocarbene ligand, two different ligand combinations, (1) organic isocyanide and chloride ligand and (2) two chloride ligands, was performed. The influence of the electronic effects of substituents in the catalyst on the reaction yield was examined.

New monomers of the biquinoline series—diyldimethanamines—have been synthesized, and polymers having biquinoline units in the main chain and their metal–polymer complexes with cuprous chloride have been obtained using these monomers. The resulting starting compounds and polymers have been studied using NMR spectroscopy, HPLC, and simultaneous thermal (thermogravimetric and differential thermal) analysis, and the mechanical characteristics of the polymers and metal–polymer complexes have been examined. It has been shown that the structure and physicochemical properties of the polymers based on synthesized diyldimethanediamines largely depend on the position of groups in the biquinoline moiety and the presence of interchain coordination bonds in the polymer.