Carbazole Copolymers Research Articles

Sensing 6-Mercaptopurine with a Thiophene-carbazole Copolymer Matrix: A First Principles Approach

This study discusses the impact of cytostatic drugs, particularly 6-mercaptopurine(6-MP), as emerging pollutants in aquatic ecosystems. Computational analyses using Density Functional Theory analyzed the electronic properties and adsorption behavior of the 3-methoxy thiophene (3-MeOTH) monomer matrix and the 3-methoxy thiophene(3-MeOTH)–n-vinyl carbazole (NVK) copolymer matrix in the presence of 6-MP. Results indicate that 6-MP is adsorbed on the matrices of 3-MeOTH polymer and 3-MeOTH-NVK copolymer with weak Van der Waal forces as indicated by negative adsorption energy and a significant charge transfer. Additionally, 6-MP shows notable sensitivities with both matrices, with 3-MeOTH-NVK demonstrating a 37.8% higher sensitivity compared to 3-MeOTH polymer. Enhanced conductance and peak amplitude enhancements in the presence of 6-MP suggest the potential of these materials for drug sensing applications.

Ftir, uv-vis and conductivity studies in a copolymer of indole and carbazole

The copolymer containing different wt% of indole and carbazole were synthesized by following in situ copolymerization method using ammonium persulfate as oxidizer, at room temperature. Crystalline and amorphous phases were noted from XRD patterns of the samples. Structural and optical studies were carried out by FTIR and UV-Vis spectroscopy. Different functional groups in the prepared copolymer have been identified and optical band gaps were determined to vary from 3.83 eV to 3.96 eV and 3.98 eV to 4.13 eV corresponding to direct and indirect transitions. Dc conductivity measured in the temperature range of 300 K to 423 K is observed to be semiconducting type. Two different regions of variation of conductivity with temperature have been observed and the corresponding activation energy was determined. The increase in conductivity and decrease in activation energy with increase of wt% of Cz content in PInCz copolymer is observed. This may be due to decrease of hopping distance of polarons with increase of Cz contents in the copolymer.

Impact of ZnO Decoration on Electronic Properties of Alkyl Substituted Thiophene–Carbazole Copolymer

This study analyzes the impact of zinc oxide (ZnO) decoration on the structure, stability and electronic properties of the alkyl-substituted thiophene-vinyl carbazole (3-MeTH-VCZ) copolymer, employing density functional theory (DFT)-based quantum atomistix toolkit (ATK) software. This analysis shows a negative interaction energy between the ZnO and the pristine 3-MeTH-VCZ, facilitating substantial charge transfer. Furthermore, the composite (3-MeTH-VCZ-ZnO) formed by the decoration of ZnO in the pristine 3-MeTH-VCZ shows improved electronic properties compared to its pristine counterpart. This improvement is evidenced by an approximate 62% reduction in the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap, confirmed by shifts observed in the molecular energy spectrum (MES) and density of state (DOS) profiles. The reduction in the HOMO-LUMO gap suggests enhanced physicochemical and electrochemical sensitivity of the synthesized composites to external stimuli, making them promising candidates for sensing and optoelectronic devices.

Anticorrosive behaviour of poly(vinyl carbazole-co-methoxy ethyl methacrylate) and its nanocomposites

A copolymer of vinyl carbazole with methoxy ethyl methacrylate [Poly (VK-co-MEM)] was prepared by free radical solution polymerization. The copolymer was reinforced with two different nanofillers namely CaCO3 and graphene by solution blending technique. The resultant polymer nanocomposites were characterized by Fourier Transform Infra-Red Spectroscopy (FTIR) and X-ray Diffraction (XRD) studies. The SEM micrographs of polymer and its nanocomposites were taken to observe the morphological changes. The IDT of the polymer and its nanocomposites were calculated using Thermogravimetric Analysis (TGA). The optical characteristic of the synthesized polymer and its nanocomposites were assessed using UV–Vis spectroscopy. The anticorrosive property of [Poly (VK-co-MEM)] and its nanocomposite coated on mild steel (MS) in 3.5% (w/v) NaCl were carried out using Potentiodynamic Polarization and Electrochemical Impedance Spectroscopy (EIS). The results show the prepared material has better protection against corrosion.

Copolymerization of aniline and 9 vinyl carbazole: A DFT study

Owing to the large surface area, high thermal stability and good conductivity, few polymers have emerged as potential candidate for the trace level detection of anticancer drugs. The present work explores the electronic properties and stability of aniline, 9 vinyl carbazole, and their copolymer (Ani-NVK), studied employing density functional theory (DFT) based approach. Analysis of stability and electronic characteristics of aniline-9 vinyl carbazole copolymer in comparison to the monomers show reduced HOMO-LUMO gap, variation in density of state (DOS) and decrease in total energy. It is observed that copolymerization enhances the designing capability of electrochemical polymeric sensor for detection, quantification, validation and determination of anti-cancer drugs in comparison to the sensors based on Aniline and 9 vinyl carbazole.

Polychalcones based on triphenylamine and carbazole building blocks via Claisen–Schmidt route

AbstractAlternating and random copolymers of carbazole and triphenylamine containing polychalcones are prepared by adopting simple Claisen–Schmidt route via A2 + B2 approach. Terephthaldehyde derivative was used as an additional comonomer along with bisaldehyde of triphenylamine to obtain a random copolymer. The prepared polymers are readily soluble in common organic solvents and the polymers exhibited narrow poly dispersity. The polymers are thermally stable and no observable degradation is observed until 350°C. Further, the spin cast thermally annealed films on glass substrate indicated corrugated surface as measured by scanning electron microscope and atomic force microscopy, which could facilitate for greater interaction at the interfaces. Photophysical properties of the polymers in solution and in thin film showed excellent emission characteristics. Both alternating and random copolymers showed a high quantum yield of 0.74 on comparison with quinine sulfate. Polychalcones with triphenylamine/carbazole showed oxidative response in cyclic voltammetry which suggested the suitability as electrochemical sensors and antioxidant coating material.

Studies on the spectral, morphological and magnetic properties of PCz-PPy copolymer encapsulated BaFe2O4 nanohybrids

Spinel structures have been widely explored due to widespread applications in anti-bacterial coatings, memory devices, photocatalysts, high frequency devices, gas sensors and electromagnetic absorbing materials. In the present study, barium ferrite spinel (BaFe2O4) was synthesized through sol–gel method and its nanohybrids with copolymers of carbazole and pyrrole were successfully synthesized via mechano-chemical mixing. The spectral, thermal, morphological and magnetic properties of the synthesized nano-magnetic materials were analyzed via thermal gravimetric analysis (TGA), Fourier transforms infrared (FT-IR) spectroscopy, diffuse reflectance spectroscopy (UV/Vis-DRS), X-ray powder diffraction method (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) techniques. IR studies confirmed the formation of BaFe2O4/poly(Cz-co-Py) nanohybrids, while the loading of copolymer in BaFe2O4 was found to be 20%, 30% and 40% respectively as confirmed by TGA study. The XRD profiles revealed the semi-crystalline nature of the nanohybrids with average crystalline size ranging between 13.90 and 33.47 nm which was calculated by Williamson Hall method. The TEM studies showed that the copolymers were deposited on the surface of BaFe2O4 nanoparticles. The nanohybrids revealed bandgap values of 2.06 eV, 1.95 eV, 1.80 eV and 1.65 eV for BaFe2O4, BaFe2O4/(PCz-PPy)-80/20, BaFe2O4/(PCz-PPy)-70/30 and BaFe2O4/(PCz-PPy)-60/40, respectively. The nanomaterials showed potential to be used as visible light active photocatalysts.

Electrochemical synthesis and characterization of copolymers of N-vinyl carbazole and methyl ethyl ketone formaldehyde resin

Purpose The purpose of this paper is to produce non-conductive copolymers of N-vinyl carbazole (NVCz) and methyl ethyl ketone formaldehyde resin (MEKFR) by the electroinduced Ce (IV) polymerization method and the electrochemical oxidization of the formed copolymer to produce their conductive green form. The non-conductive and conductive copolymers were characterized by using Fourier transform infrared, solid-state conductivity and spectroelectrochemical, chronoamperometric, cyclovoltammetric and electrochemical impedance spectroscopic measurements. Design/methodology/approach The chronoamperometric electropolymerization of white, insulator form of the copolymer of NVCz and MEKFR (copolymer 1) on to Pt electrode was carried out and the green coloured film of the MEKFR-ox-NVCz copolymer (copolymer 11) was produced in the doped and conductive form. All reactions were performed in dichloromethane containing 0.1 M BU4NClO4. Copolymer 11 films obtained on the surface of the working electrode were removed and washed in acetonitrile and dried at room temperature before characterization. The results were compared with the copolymer obtained by electrochemical oxidation of MEKF-R and NVCz (copolymer 2). Findings The insulating copolymer of NVCz and MEKFR (copolymer 1) was produced by the electroinduced Ce (IV) polymerization method and converted into the conductive form electrochemically on the surface of the Pt electrode (copolymer 11). The polymers were characterized by electrochemical, spectrophotometric and conductivity measurements. The ionization potentials, optical band gap, peak potentials Ep, doping degree and specific capacitance of the copolymer 11 were obtained. The conductivity of the copolymer 11 is lower than the PNVCz and higher than the copolymer obtained by electrochemical oxidation of MEKF-R and NVCz (copolymer 2). The copolymer 11 has a lower onset potential than PNVCz and the copolymer 1 and slightly higher band gap than PNVCz. The capacitive behaviours of the copolymer 11 were very close to PNVCz. Research limitations/implications This study focuses on obtaining a green and conductive form of the copolymer of NVCz and MEKFR with the electrochemical method by using a white and insulator form of the same copolymer. Practical implications This work provides technical information for the synthesis of conducting copolymer of NVCz and MEKFR. Social implications These copolymers may be in the field of PNVCz applications such as photoconductivity and corrosion inhibition. Originality/value Electroinduced Ce (IV) MEKFR redox system was applied for the polymerization of NVCz monomer to produce the copolymer 1. The conductive copolymer 11 was synthesized through electrochemical oxidative coupling of the carbazole groups of the copolymer 1.

Insights into the π - π interaction driven non-covalent functionalization of carbon nanotubes of various diameters by conjugated fluorene and carbazole copolymers.

We investigate the interaction of polyfluorene and fluorene/carbazole copolymers bearing various functional groups and side chains with small to large diameter-from 1.7 nm to 9 nm-carbon nanotubes (CNTs) in vacuo. We use variable-charge molecular dynamics simulations based on the reactive force field ReaxFF. We show that non-covalent functionalization of nanotubes, driven by π - π interactions, is effective for all the polymers studied, thanks to their conjugated backbone and regardless of the presence of specific functional groups. The geometry at equilibrium of these polymer/CNT hybrids is analyzed in detail at the scale of each fluorene or carbazole unit. The role of both the functional groups and the alkyl chain length is analyzed in detail. Adsorption of the polymers on the nanotube sidewalls is shown to be either complete-with the whole chain physisorbed-or partial-due to intrachain coiling or interchain repulsion-depending on the initial geometry, number of polymers, and nanotube diameter. Energetic arguments supplement the described geometric features. Both energetic and geometric adsorption features are derived here for the first time for large diameter carbon nanotubes (up to 9 nm) and fluorene/carbazole copolymers having up to 30 monomers and bearing different functional groups. The force field ReaxFF and its available parameterization used for the simulations are validated, thanks to a benchmark and review on higher-level quantum calculations-for simple π - π interacting compounds made up of polycyclic aromatic molecules adsorbed on a graphene sheet or bilayer graphene. Although it is shown that the influence of the nanotube chirality on the adsorption pattern and binding strength cannot be discussed with our method, we highlight that an available force field such as ReaxFF and its parameterization can be transferable to simulate new systems without specific re-parameterization, provided that this model is validated against reference methods or data. This methodology proves to be a valuable tool for optimal polymer design for nanotube functionalization at no re-parameterization cost and could be adapted to simulate and assist the design of other types of molecular systems.

Molecular base and interfacial enrichment of chain entangle in amorphous conjugated polymers: Role of racemic alkyl side groups

Abstract Clear structure characterization is the basics of performance analysis, which is difficult for the complex structure of amorphous conjugated polymers. In this work, we have given solid evidence in copolymer of fluorene and carbazole that the carbazole with racemic branched alkyl side chain tend to form chain entanglement in high concentration of solution and thin film. The single crystal structure of two racemic carbazole dimer with stronger π-π interaction, which 1HNMR peaks is well corresponding to that of racemic polymer at high concentration and proves the existence of chain entanglement in racemic polymer. The chain entanglement segment with high molecular weight and low energy level (estimated as about 3% and absent in the chiral polymer) have enriched at the interface during film fabrication, which induce strong charge trapping and excited state quenching during the working of optoelectronic devices. These chain entanglement would be well restrained by chiral substitution, which induce one order of magnitudes improvement of device brightness and efficiency. These results indicate that the chain entangle at interface and charge trapping play the key role of bad device performance, which help to explore the instability origin and performance promotion.

Synthesis and characterization of electroactive polymers containing carbazole and harmane groups

ABSTRACTWe have synthesized three types of polymers: carbazole (P1), norharmane (P2), and carbazole and harmane copolymer (P3). The optical properties and photophysical properties of these polymers were fully investigated and the relationship between polymer structure and the electroluminescence properties of OLED device was systematically investigated herein. The three polymers represent high thermal stability and widely optical band gaps (ΔEg) over 2.78 eV. The best device performance based on copolymer demonstrates the maximum luminance (L) of 11096 cd/m2, luminance efficiency (LE) of 37.9 cd/A, and power efficiency (PE) of 10.6 lm/W.

Copolymers of carbazole and phenazine derivatives: minor structural modification, but totally different photodetector performance

Through the subtle modification of the molecular structure, four donor–acceptor type conjugated polymers were designed, and demonstrated very different device performances with the highest photodetectivity achieved up to 6.2 × 1012 Jones.

Tuning the spectral, thermal and fluorescent properties of conjugated polymers via random copolymerization of hole transporting monomers

Effect of copolymerization on the fluorescent properties of polycarbazole and poly(o-phenylenediamine).

Dual substitution at 4,9-positions of carbazole in donor-π-acceptor copolymer enhances performance of bulk-heterojunction organic solar cells

Several carbazole-2,7-diyl units with alkoxy substituents at the 4-position in addition to branched (1-alkyl)alkyl substituents at the 9-position were developed and combined with difluorinated dithienylbenzothiadiazole by using a Suzuki coupling reaction to synthesize donor–π–acceptor-type copolymers. X-ray diffraction analyses of these copolymers revealed that the 4,9-disubstituted carbazole unit contributed to form a balanced interdigitated structure, which resulted in smaller π-stacking distances (4.0–3.5 Å) of the polymer backbone, a narrower bandgap (2.0–1.8 eV), and higher hole mobilities (4.2 × 10−4 to 2.9 × 10−3 cm2 V−1 s−1) than those of the carbazole copolymer without the 4-substituent (PCDT2FBT). A bulk heterojunction organic photovoltaic device with a configuration of ITO/PEDOT:PSS/polymer:PC70BM/LiF/Al exhibited a power conversion efficiency of 5.46%, a short-circuit current density of 12.4 mA cm−2, a fill factor of 0.58, and an open-circuit voltage of 0.76 V. The photovoltaic performance was much higher than that of PCDT2FBT. These results demonstrate that incorporation of the side chains into the 4,9-positions of carbazole is a novel approach to obtain self-organizing carbazole polymers, enabling improvement in light absorption, hole mobility, and photovoltaic performance.

Bulk heterojunction solar cells made from carbazole copolymer and fullerene derivative with an inserted layer of discotic material with improved efficiency

ABSTRACTBulk heterojunction photovoltaic cells based on composites of copolymer poly [N-90-hepta-decanyl-2,7-carbazole-alt-5,5-(40,70-di-2-thienyl-20,10,30-benzothiadiazole)] and the fullerene derivative [6,6]-phenyl C71-butyric acid methyl ester with an inserted layer of discotic liquid crystalline material (2, 3, 6, 7, 10, 11-hexabutyloxytriphenylene) between the interface of active layer and hole transporting layer has been reported. Different hole transporting layers deposited on indium tin oxide substrates such as poly (3,4-ethylenedioxythiophene)-poly (styrenesulphonate) or molybdenum trioxide has been used in these devices. All the devices with inserted discotic liquid crystal layer showed better performance than the reference cells. Power conversion efficiency of 5.14% was achieved for these photovoltaic solar cells containing self-organised discotic liquid crystal layer of 30 nm thickness under one sun condition which is substantial jump as compared to earlier reports. The mobility of holes in the discotic liquid crystal inserted devices was found to be of the order of 10–6 cm2 V–1 s–1 due to which high values of current density was achieved. The influence of varying the thickness of liquid crystal layer and annealing on the photovoltaic parameters of these devices was also studied.

Synthesis and Characterization of novel Thiophene and Carbazole-based Polymers – Optical and Electrochemical Characterization

A donor/acceptor series of carbazole copolymers, composed of alternating 2,7-linked 3,6-difluoro-9-(1-octyl-nonyl)-carbazole units and bithiophene repeated units [P1], 5,7-bis(5-bromothiophen-2-yl)-2,3-bis(4-(2-ethylhexyloxy) phenyl) thieno[3,4-b]pyrazine repeated units [P2] and bithiophene mixed with 5,7-bis(5-bromothiophen-2-yl)-2,3-bis(4-(2-ethylhexyloxy) phenyl) thieno[3,4-b]pyrazine repeated units [P3] have been prepared following Suzuki polymerisation procedures. The route of synthesis and characterisation techniques of this novel class of materials, together with their photo-physical and electrochemical properties are presented in this study. The polymers were characterised by 1H NMR, 13C NMR and Elemental Analysis. Molecular weights were estimated using gel permeation chromatography (GPC). The thermal stability behaviour for polymers was investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The electronic and photo-physical properties were investigated by use of cyclic voltammetry (CV) and UV-Vis spectroscopy, respectively.

Polyphenylbenzene as a platform to fabricated blue-emitting polymers: The effect of aggregation inhibition and application in PLED

The modification of polyfluorene is of significance. Here according to the two factors that influence the blue emission, we design and synthesize two copolymers which contain polyphenylbenzene and fluorene, polyphenylbenzene and carbazole, respectively. Thermogravimetric analysis (TGA) results conforms that the introducing of polyphenylbenzene unit can improve thermal stability of the polymer. Through the research of photophysical data and comparing with copolymers contain benzene unit, we get that the polyphenylbenzene unit can not only largely improve the solubility, but also effectively inhibit the contaction between polymer chains. This can guarantee the original blue emission even in solid state. Theoretical calculation results show that in the optimized structures, the dihedral angle between polyphenylbenzene and fluorene unit is 61.1°, bigger than that in the polyphenylbenzene and benzene copolymer (36.9°). This further conform that the introducing of polyphenylbenzene unit can make polymers twisted and reduce conjugation. Also, the formation of excimers can be inhibited which can guarantee blue emission. Based on their good emission efficiency and stability, we fabricated polymer light emission diodes using them as light emission layers. Devices results show that polyphenylbenzene and carbazole copolymer can exhibit better deep-blue emission, the CIE can stay at (0.19, 0.13). All these results show that the polyphenylbenzene unit can be used as an effective building block to fabricate polymer with deep-blue emission.

Anion exchange membranes based on carbazole-containing polyolefin for direct methanol fuel cells

A series of anion exchange membranes was prepared from the copolymer of 1-vinyl imidazole and N-vinyl carbazole for direct methanol fuel cells (DMFCs). The structure of the membranes was studied using 1H NMR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and small angle X-ray scattering (SAXS). The thermal stability of the membranes was characterized by thermo-gravimetric analysis (TGA). The ion conductivity, methanol permeability, ionic exchange capacity (IEC), water uptake, swelling ratio, and alkaline stability of the membranes were investigated. It is found that the ion conductivity of the membranes varied from 9.34×10−2 to 20.28×10−2Scm−1 in deionized (DI) water and the methanol permeability varied from 4.5×10−8 to 12.3×10−8cm2s−1 at 30°C. All the as-prepared membranes are stable in a 1.0M KOH solution at 60°C for 1400h due to the polyolefin backbone. A methanol/O2 single cell evaluation exhibited an open circuit voltage of 0.93V and peak power density of 125.8mWcm−2. Therefore, the as-prepared membranes have great potential for application in alkaline fuel cells.

Electrochemical copolymerization of carbazole and 2,2′:5′-2″ terthiophene: characterization and micro-capacitor application

In this paper, a copolymer of carbazole (Cz) and 2,2′:5′,2″-terthiophene (TTh) was electropolymerized in 0.1 M sodium perchlorate (NaClO4)/acetonitrile (CH3CN) on glassy carbon electrode. The optimum conditions of resulting homopolymers of Cz, TTh and copolymer of Cz and TTh in the initial feed ratio of [Cz]0/[TTh]0 = 1/10 were characterized by cyclic voltammetry, Fourier-transform infrared-attenuated total reflectance, scanning electron microscopy, energy dispersive X-ray analysis, and electrochemical impedance spectroscopy. Morphological analysis of copolymer shows that a micro-spherical and web-like morphology was formed for copolymer at different initial feed ratios of [Cz]0/[TTh]0 = 1/2, 1/5 and 1/10. The capacitive behavior of the modified electrodes was defined via Nyquist, Bode-magnitude, and Bode-phase plots. The highest low-frequency capacitance (C LF) was obtained as 4.11 mFcm−2 in the initial feed ratio of [Cz]0/[TTh]0 = 1/10. Double-layer capacitance (C dl) and phase angles (θ) were obtained for homopolymer and copolymer systems. The highest C dl was obtained as 2.01 mFcm−2 for the copolymer in the initial feed ratio of [Cz]0/[TTh]0 = 1/2. The highest phase angle of copolymer was obtained as θ = ~75° in the initial feed ratio of [Cz]0/[TTh]0 = 1/1. These capacitance results confirmed that films of copolymer Cz/TTh are promising materials for micro-capacitor applications.

Thioalkyl-Substituted Benzothiadiazole Acceptors: Copolymerization with Carbazole Affords Polymers with Large Stokes Shifts and High Solar Cell Voltages

Copolymers of carbazole and 4,7-bis(2-thienyl)-2,1,3-benzothiadiazole (dTBT) incorporating thioalkyl (−SR) and alkoxy (−OR) solubilizing groups on the 2,1,3-benzothiazdiazole (BT) unit are synthesized and compared. The introduction of −SR and −OR groups onto the BT unit of the polymer was found to have different effects on the electronic properties of the polymers as well as the conformation of the polymer backbone. Large conformational changes between the ground state (GS) and excited state (ES) geometries of the polymers with −SR groups led to very large Stokes shifts of up to 224 nm. The polymer with −OR groups was found to have approximately double the photovoltaic efficiency at ∼4% compared to the polymers with −SR groups (PCE ∼ 2%). However, polymers with −SR groups were found to give very high open circuit voltages (VOC) of over 1 V. Changing the −SR chain length from ethyl to dodecyl was found to have little influence on the solar cell performance of the polymer or the magnitude of the Stokes shift.