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Recent advances with electro-optic polymers
摘要： In recent years the electro-optic polymers emerged as an important branch of material science. This growth and interest is fundamentally motivated by practical application of these materials in second-order nonlinear optics and in waveguiding configuration. Indeed, these materials marry excellent optical quality of amorphous r bonded polymers with enhanced first hyperpolarizability of imbedded organic nonlinear optical molecules. Although a big progress was achieved with them, concerning particularly the science, understanding and applications, some problems remain still incompletely solved, particularly the stability of induced polar order by the application of external electric field and the molecule aggregation. In this review paper we recall techniques of thin film fabrication, poling, characterization of NLO properties and discuss more precisely problems of molecule aggregation as well as the temporal decay of polar order. A novel 3D second-order NLO chromophores, namely the [2] paracyclophanes, which may help to limit the aggregation, are proposed. We show, in particular, that this molecule can be poled in doped PMMA thin films. Practical applications of electro-optic polymers are also reviewed and discussed.
关键词： pockels effect,electro-optic polymers,electric field poling,first hyperpolarizability,second harmonic generation,[2] paracyclophane,functionalized polymers
更新于2025-09-23 15:21:01
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Photoactive Functional Soft Materials (Preparation, Properties, and Applications) || Photoresponsive Soft Materials Based on Reversible Proton Transfer
摘要： Proton transfer is one of the most fundamental processes in nature and numerous chemical, material, and biological processes are driven by proton transfer. For example, biological systems use proton gradient as an energy form to synthesize ATP for their biological functions; many organic reactions are catalyzed by Bronsted acids; and many materials have pH‐sensitive properties. Proton transfer is also involved in different aspects of polymer science relative to preparation, property, and processing. For example, cationic polymerizations can be initiated by proton transfer from a strong acid to a monomer. It has been reported that many polymers are sensitive to the pH (proton concentration) of the environment, and their properties including mechanical, geometrical, electric, optical, and magnetic properties, change with pH due to proton transfer between the polymers and the environment. Polymers with acid‐labile bonds have been studied for drug delivery; and photoinduced cationic polymerization using photoacid‐generators (PAGs) has been applied to photolithography.
关键词： Proton transfer,photoacid,fragrant‐releasing polymers,photoresponsive nanoparticles,photochromic materials,photoresponsive polymers,reversible
更新于2025-09-23 15:21:01
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Trap-Controlled White Electroluminescence From a Single Red-Emitting Thermally Activated Delayed Fluorescence Polymer
摘要： Single white-emitting polymers have been reported by incorporating the second-generation carbazole dendron into the side chain of a red-emitting thermally activated delayed ?uorescence (TADF) polymer. Due to the prevented hole trap effect, in this case, excitons can be generated simultaneously on the polymeric host and the red TADF dopant to give a dual emission. Consequently, a bright white electroluminescence is achieved even at a dopant loading as high as 5 mol.%, revealing a maximum luminous ef?ciency of 16.1 cd/A (12.0 lm/W, 8.2%) and Commission Internationale de l’Eclairage (CIE) coordinates of (0.42, 0.32). The results clearly indicate that the delicate tuning of charge trap is a promising strategy to develop ef?cient single white-emitting polymers, whose low-band-gap chromophore content can be up to a centesimal level.
关键词： carbazole dendron,thermally activated delayed ?uorescence (TADF),dual emission,charge trap,single white-emitting polymers
更新于2025-09-23 15:21:01
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Preparation and comparison of molecularly imprinted polymer fluorimetric nanoprobe based on polymer dots and carbon quantum dots for determination of acetamiprid using response surface method
摘要： In this study molecularly imprinted polymers (MIP) based on carbon quantum dots (CQDs) and polymer dots (PDs) are developed for selective determination of acetamiprid using fluorometry. The measurement is based on the fluorescence quenching of CQDs and PDs in the presence of acetamiprid. PDs were prepared using a one-step aqueous synthesis method from ascorbic acid and diethylenetriamine at room temperature. CQDs were prepared from the same materials using the hydrothermal method at 180 °C. These particles were characterized using field emission scanning electron microscopy (FE-SEM), FTIR, dynamic light scattering (DLS), X-ray diffraction (XRD), UV–Vis, and fluorescence. The quantum yield was 47% for PDs and 8% for CQDs. Then, molecularly imprinted polymers (MIP) were prepared based on PDs and CQDs using reverse microemulsion method. The fluorescence quenching of CQD@MIPs and PD@MIPs was investigated at an excitation wavelength of 350 nm and emission wavelength of 440 nm in the presence of a template. Other variables affecting the fluorescence peaking were optimized using design expert software. The results illustrate that the use of PD@MIPs had a wide dynamic range 0.08–109 nmol L?1, good accuracy and detection limit of 0.02 nmol L?1, while using CQD@MIPs led to a lower dynamic range 0.36–64 nmol L?1, and detection limit of only 0.11 nmol L?1. The responses of the optical nanoprobe for acetamiprid in water (recovery 92–102%) and apple (recovery 92–103%) were also investigated.
关键词： Molecularly imprinted polymers,Fluorescence quencing,Carbon dots,Polymer dots,Optical nanoprobe,Acetamiprid
更新于2025-09-23 15:21:01
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[IEEE 2018 4th IEEE International Conference on Emerging Electronics (ICEE) - Bengaluru, India (2018.12.17-2018.12.19)] 2018 4th IEEE International Conference on Emerging Electronics (ICEE) - Development of New Blue-Light Emitting PPV Block Copolymer: Synthesis, Characterization and Electro-Optical Studies
摘要： New soluble intense blue light emitting bulky ring substituted segmented PPV block copolymer was synthesized by synthesized condensation polymerization. Rigid cyclohexyl methoxy group substituted distyrylbenzene unit was the chromophore group present in the synthesized segmented block copolymer. The obtained copolymer was dissolved in all common organic solvents. The structure of the copolymer was characterized by using FT-IR, NMR techniques, and elemental analysis. GPC analysis shows that the copolymer has narrow polydispersity index. Thermal gravimetric analysis shows it has excellent thermal stability with maximum decomposition temperature obtained as 4220C. The HOMO and LUMO values of copolymer were estimated from the cyclic voltammograms. Photoluminescence studies show that copolymer gives blue emission. XRD and DSC studies give information about the semi-crystalline nature of the present copolymer. Overall results such as thermal properties, photoluminescence characteristics and low onset voltage from Voltage vs. Current data are confirmed the suitability of the copolymer for fabricating PLEDs.
关键词： polymer light emitting diodes,light emitting polymers,segmented block copolymer
更新于2025-09-23 15:21:01
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Readily Accessible Benzo[d]thiazole Polymers for Nonfullerene Solar Cells with >16% Efficiency and Potential Pitfalls
摘要： Here we report facile, high-yield synthetic access to the difluoro BTA building block, 4,7-bis(5-bromo-4-(2-hexyl-decyl)-thiophen-2-yl)-5,6-difluoro-2-(pentadecan-7-yl)-benzo[d]thiazole (BTAT-2f) for use in Donor (D)-Acceptor 1(A1)-D-Acceptor 2(A2) polymers [D = bithiophene, A1 = BTA-2f, A2 = benzothiadiazole (BT) derivative] for organic solar cells (OSCs). Fine tuning of polymer optical and electronic properties is achieved by incrementally varying the A2 fluorination level. Bulk-heterojunction (BHJ) PBTATBT-4f:Y6 solar cells deliver a noteworthy power conversion (PCE) efficiency of 16.08 % (Voc =0.81 V, Jsc =27.25 mAcm-2, FF =72.70 %) without processing additives. In contrast, PBTATBT-2f:Y6 exhibits an irregular morphology and low PCE, ascribable to co-crystal formation-induced recombination, which is unprecedented for non-fullerene (NFA) OSCs. This result should be of guiding significance for future NFA design.
关键词： Benzo[d]thiazole Polymers,Power Conversion Efficiency,Organic Solar Cells,Co-crystal Formation,Nonfullerene Solar Cells
更新于2025-09-23 15:21:01
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Synthesis of eight isostructural 2D lanthanide coordination polymers assembled by rigid furan-2,5-dicarboxylic acid and flexible adipic acid as linkers and exploration of luminescent Eu/Tb polymers as efficient and sensitive sensors for nitroaromatic compounds
摘要： Detection of hazardous chemicals is crucial for a healthy and safe environment as well as for the well-being of humans. A confluence of chemistry and engineering continues to improve the sensitivity and selectivity for several classes of harmful chemicals with the promise of cheap and portable sensing. Herein, following the function-oriented research strategy, eight novel lanthanide coordination polymers (Ln-CPs) have been successfully assembled with the framework composition [Ln(2,5-FDC)0.5(Adip)(H2O)2] (Ln = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6), Ho (7), Er (8), 2,5-FDC2? = furan-2,5-dicarboxylate, Adip2? = Adipate) under solvothermal synthesis conditions. The structural analysis indicates that all the eight CPs have the same structural features. All compounds crystallize in the orthorhombic crystal system (space group Pnma) with point symbol {33·44·53} and consist of 2D cem topological type. The linkers 2,5-FDC2? and Adip2? exhibit μ2-κ4,Z1:Z1:Z1:Z1 and μ3-κ5,Z2:Z1:Z1:Z1 coordination modes respectively. The as-synthesized polymers were characterized by powder X-ray crystallography, infrared spectroscopy, thermogravimetric analysis, and photoluminescence studies. CP-3 and CP-5 are promising luminescent lanthanide coordination polymers (Ln-CPs) and function as efficient sensors for the detection of nitroaromatic compounds at the ppm level in mix N,N′-dimethyl formamide-aqueous medium via the luminescence quenching mechanism.
关键词： furan-2,5-dicarboxylic acid,lanthanide coordination polymers,adipic acid,luminescent sensors,nitroaromatic compounds
更新于2025-09-23 15:21:01
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The synthesis of CdSe quantum dots stabilized by polymers and polyelectrolyte capsules
摘要： The formation of nanocomposites based on quantum dots and polymers is a way of combining the benefits of quantum dots, such as their fundamental novelty and biomedical perspectives, with technological capabilities of polymers. The aim of this work was to synthesize cadmium selenide (CdSe) quantum dots in the presence of polymers (polyethyleneimine and chitosan) in an aqueous solution and embed cadmium selenide/polymer nanoparticles into polyelectrolyte capsules. To characterize the polymer-stabilized cadmium selenide quantum dots, the authors used fluorescence spectroscopy and dynamic and electrophoretic light scattering methods. The morphology of cadmium selenide/polymer nanoparticles characterized by the method of transmission electronic microscopy. The incorporation of quantum dots into a polymer matrix can significantly reduce their toxicity and prolong the duration of their fluorescence signals. Cadmium selenide nanoparticles stabilized by chitosan were used to synthesize five-layered polyelectrolyte capsules.
关键词： nanoparticles,polymers,biomaterials
更新于2025-09-23 15:21:01
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Single-Stage Formation of Film Polymer Composites in Supercritical Colloid Solutions of Nanoparticles Obtained by Laser Ablation
摘要： A review of earlier studies is presented together with new results on the creation of highly concentrated colloid solutions with nanoparticles of noble metals (gold and silver) in a supercritical carbon dioxide (SC–CO2) medium and the development of a single-stage method for the production of polymer nanocomposites. The effect of the SC–CO2 density on the dynamics of the formation and decomposition of supercritical fluids (SCFs) of silver and gold nanocolloids in the process of pulsed laser ablation and after its termination is studied. The possibility of the formation of colloids from bimetallic nanoparticles was considered. The effective dielectric permittivity of a colloid solution of silver nanoparticles in SC–CO2 is calculated by the numerical modeling of extinction spectra in the dipole approximation at various densities, with consideration for the size of nanoparticles and the degree of their asphericity. The formation of various film nanocomposites based on a porous copolymer polytetrafluoroethylene—vinylidenefluoride with ruby nanoparticles and two modifications of pure porous polytetrafluoroethylene with silver nanoparticles in the same SCF reactor and with a single technological process is considered.
关键词： bimetallic nanoparticles,film nanocomposites,nanocolloid,supercritical carbon dioxide,porous polymers
更新于2025-09-23 15:21:01
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Peripheral RAFT Polymerization on a Covalent Organic Polymer with Enhanced Aqueous Compatibility for Controlled Generation of Singlet Oxygen
摘要： A covalent organic polymer (COP) is prepared by 4,4’,4’’,4’’’-(porphyrin-5,10,15,20-tetrayl)tetraaniline (TAPP) with 4,4’-(anthracene-9,10-diyl)dibenzoic acid (ADDA) via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide/4-dimethylaminopyridine coupling. The COP is further modified with a hydrophilic polymer, poly(poly(ethylene glycol) methyl ether methacrylate) by grafting-from reversible-addition-fragmentation chain transfer (RAFT) polymerization to enhance its solubility in various solvents. The modified COP can bind singlet oxygen through the formation of endoperoxide by ADDA upon the exposure to red light irradiation. Singlet oxygen can be then released via the photodynamic mechanism or the cycloreversion by endoperoxide when heated at 110 8C. These results open new possibilities for simultaneous generation of singlet oxygen by the photodynamic route and singlet oxygen carriers, demonstrating promise for treating hypoxic tumors.
关键词： endoperoxides,grafting-from,covalent organic polymers,singlet oxygen,photodynamic mechanism
更新于2025-09-23 15:21:01