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Raman spectra of polyaniline thin films electropolymerized in the presence of (a) 1 M and (b) 2 M dopant acid concentrations.
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Polyaniline (PANI) thin films have been electrochemically synthesized onto conducting glass substrates. The current study demonstrates that the properties of PANI films depend on the concentration of dopant acid. Well-adherent PANI coatings were obtained under potentiodynamic conditions during sequential scanning of the potential region between -0....
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... As observed in Figure 2c, the bands appeared in the range of 400-2000 cm −1 , corresponding to different stretching and vibrational modes. The bands in the range of 400-1100 cm −1 correspond to the deformation vibration of benzene rings [64]. The band located at 816 cm −1 is attributed to the in-plane vibration of protonated polyaniline. ...
The measurement of glucose concentration is a fundamental daily care for diabetes patients, and therefore, its detection with accuracy is of prime importance in the field of health care. In this study, the fabrication of an electrochemical sensor for glucose sensing was successfully designed. The electrode material was fabricated using polyaniline and systematically characterized using scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and UV-visible spectroscopy. The polyaniline nanofiber-modified electrode showed excellent detection ability for glucose with a linear range of 10 μM to 1 mM and a detection limit of 10.6 μM. The stability of the same electrode was tested for 7 days. The electrode shows high sensitivity for glucose detection in the presence of interferences. The polyaniline-modified electrode does not affect the presence of interferences and has a low detection limit. It is also cost-effective and does not require complex sample preparation steps. This makes it a potential tool for glucose detection in pharmacy and medical diagnostics.
... The formation of the PANI shell is also evident from Raman experiments (pronounced peaks at approx. 1179, 1344, 1514, and 1599 cm −1 for Au@ATP-PANI and 1174, 1343, 1513, and 1593 cm −1 for Au@PANI) (Fig. 2c) [40]. These Raman measurements furthermore showed that the signal characteristic of the C-S stretch remained for the measurements conducted at the Au@ATP-PANI sample [37]. ...
The chemical binding between metal nanoparticles and (semi-)conductive polymer layers is essential to control the (opto-)electronic properties of such hybrid materials. Current approaches that achieve a conjugated binding of organic (semi-)conductive ligands to metal nanoparticles demonstrated promising functional properties, but are based on tedious multi-step organic synthesis to incorporate the required binding moieties at the chain ends of targeted macromolecular species. Herein, we explore the pre-functionalization of gold nanoparticles with p-aminothiophenol and subsequent surfactant-assisted formation of a poly(aniline) (PANI) shell as a means to access gold/PANI core–shell-type nanoparticles with enhanced conductive properties. Controlled surface deposition of these hybrid nanoparticles is achieved via template-assisted self-assembly. For these surface-deposited nanoparticles, charge transport properties are characterized at the nanoscale by conductive atomic force microscopy measurements and show a significant conductivity increase of our core–shell particles as compared to reference particles formed by conventional surfactant-assisted PANI-shell formation.
Graphical Abstract
... 47−49 The peaks at 840, 784, and 747 cm −1 observed in the PANI spectrum are attributed to benzene-ring deformations of substituted aromatic rings, which includes phenazine-like structures. 44,45,50 These peaks are also present in PD1, PD2, and PD3 but again at longer wavelengths. ...
This study explores conducting polymers with side chains containing long, branched alkyl groups as candidates for corrosion suppression coatings. These polymers, containing carbazole, phenothiazine, and phenoxazine cores, may be considered as analogues to polyaniline, which is often employed in corrosion control applications. The polymers are prepared from the corresponding dibrominated carbazole, phenothiazine, and phenoxazine mono-mers with 2,5-dimethyl-1,4-phenylenediamine by the Buchwald−Hartwig coupling reaction. The effectiveness of these coatings for corrosion suppression was tested by potentiodynamic polarization studies and electrochemical impedance spectroscopy. The morphology of the coatings was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Corrosion testing of coated AISI 4130 steels in 3.5 wt % NaCl showed that the phenothiazine-and carbazole-containing polymers display excellent corrosion resistance. The protection efficiency (PE) of 95.9% for phenothiazine outperformed the other polymers, including polyaniline coating. SEM images indicate that the polymers are still uniformly coated with stable morphology after 24 h of exposure to corrosive media. These results suggest that phenothiazine-and carbazole-based PANI analogues may be candidates for protective organic coatings in transportation, aviation, marine, and oil and gas industrial applications.
... A small hump appeared around 350 nm is due to the band edge absorption in the ultraviolet region [39]. The absorption spectrum of WS 2 -PANI exhibited distinct peaks, one at 337 nm corresponding to π-π transitions, and another at 640 nm ascribed to the transitions induced by polarons [40]. To investigate the influence of varying concentrations of WS 2 on PANI, we estimated the bandgap energy using Tauc's plot, as depicted in Fig. 3b. ...
... Rights reserved. [55,56]. Pure CaTiO 3 showed single luminous band centering around 429 nm [57]. ...
In this work, pristine calcium titanate (CaTiO3), polyaniline (PANI), binary PANI@carbon black (CB), and ternary PANI@CB/CaTiO3 composites were synthesized using solid-state and in situ oxidative polymerization method. XRD, FTIR, UV–Vis, PL, FE-SEM, and EDX analyses were studied in order to examine the structural, optical, and morphological properties of all grown samples. XRD, FTIR, FESEM, and EDX findings confirmed the formation of successful chemical organization among PANI, CaTiO3, and CB. The UV–Vis and PL investigation reaffirmed the reduction in optical band gap (2.67 eV–2.56 eV) and charge carrier recombination process due to inclusion of CaTiO3 into CB-reinforced polymer matrix. In photocatalytic experiment, PANI@CB/10%CaTiO3 catalyst showed efficacious performance to degrade the synthetic dyes (99.7% MO and 97.8% MB) after 120-min sunlight irradiation with higher rate and superb stability up-to 5th cycle against MO dye. In kinetic examination, pseudo-first-order kinetic model was obeyed by both dyes. Herein, the bulk heterojunction (BHJ) photovoltaic cell was fabricated by spin-coating the grown samples on FTO glass substrate and thermally evaporating the Al electrode subsequently. The BHJ fabricated by PANI@CB/10%CaTiO3 showed better efficiency (0.541%), photocurrent density (Jsc) (4.21 mA/cm²), and open-circuit voltage (Voc) (0.39 V).
Graphical abstract
... Strong Raman band at 1170 cm − 1 corresponds to the C-H vibrations of aromatic rings. Raman band in the range of 1000 to 400 cm − 1 provides insight into the deformation vibrations of benzene rings [48]. Bands at 806.3 and 415 cm − 1 correspond to in-plane and out-of-plane vibrations of the ring of the protonated emeraldine form of PANI [49]. ...
In the present study, in situ polymerization of anilinium hydrochloride over V2O5 was used to prepare PANI nanocomposites with varying weight percentage of V2O5 (10, 20, and 30 wt.%). V2O5 nanoparticles were synthesized using a simple chemical approach and their purity was confirmed through Rietveld refinement. It confirmed the advantageous electrochemical activity of V2O5 with a higher oxidation state of vanadium (V+5), enabling efficient electron storage. For fabricated electrode materials, the pair of redox peaks as well as their shape in CV suggests the faradic pseudocapacitive properties. Among all prepared electrodes, 20 wt.% V2O5-PANI (PV2) nanocomposite demonstrates maximum specific capacitance of 820.5 Fg−1 at a current density of 1 Ag−1 with decent capacitive retention of 88% after 1000 charge-discharge cycles. PV2 electrode also has a lower charge transfer resistance (Rct) of 0.5 Ω and lesser solution resistance (Ro) of 0.31 Ω in 6M KOH electrolyte which is also responsible for good electrochemical performance. The higher capacitance value and decent stability of PV2 confirmed its ordered structure with more active sites shown through FESEM, which significantly contributes to efficient ion and electron transfer. In addition, the symmetric supercapacitor configuration of PV2 electrodes exhibits good energy and power densities of 4.6 Wh kg-1 and 80.7 W kg-1, respectively. Finally, the ignition of a red LED using three PV2//PV2 symmetric devices connected in series underscores its potential to advance energy storage applications.
... Figure 14a shows that in the PL spectra of PANI with different morphologies, a peak from 450 to 451 nm is observed which is corresponded to the π-π* electronic transition related to the benzenoid rings in the polymer [42]. Besides, another emission peak was observed at a visible region which is around 468-469 nm which revealed the transition from polaronic to π band due to the de-excitation from polaron band of PANI [43,44]. Based on the PL spectra, the most intense emission band observed is in NF-PANI (58927 a.u.) disclosed that NF-PANI might experience lower photocatalytic activity (16.7%) compared to other PANI samples due to the high eh + recombination rate, which is consistent with the outcomes in poor photodegradation of 16.7%. ...
Photocatalysis is widely used for wastewater treatment as it is environmentally friendly through elimination of harmful organic compounds by mineralizing it to carbon dioxide and water under light illumination. Morphology control of polyaniline (PANI) is thought to affect the specific surface area and conductivity of the composites which subsequently contribute toward the photodegradation performance. In this research study, a binary system of PANI–TiO2 photocatalyst with different morphologies including nanotubes, nanofibers, nanospheres, star micro-/nanostructure and leaf micro-/nanostructure was fabricated for photodegradation of reactive black 5 (RB5) dye under visible light irradiation. Based on the characterization, PANI–TiO2 composites managed to reduce band gap to 2.68–2.72 eV which is proven to be easily activated under visible light region. Meanwhile, the photoluminescence analysis showed that the electron hole (e⁻h⁺) recombination was also retarded to provide opportunity for more radical generation. The PANI nanotubes (NT-PANI–TiO2) demonstrate highest photodegradation efficiency of 54.4% after 2 h. Interestingly, PANI leaf micro-/nanostructure (L-PANI–TiO2) shows highest increment of 35.3% of L-PANI to 48.8% of L-PANI–TiO2. This demonstrates the effectiveness of PANI nanotubes and leaf structures along with TiO2 as potential photocatalyst composite.
... For the PANI (emeraldine salt), Raman band at 1604 cm − 1 is related to the C-C stretching vibration of benzene ring. The intense band observed at 1170 cm − 1 is assigned to C-H vibrations of aromatic rings [33]. The bands at 874, 812 and 414 cm − 1 correspond to out-of-plane deformations of the rings protonated emeraldine form of PANI [34]. ...
A cost-effective method for obtaining polyaniline coated magnesium cobalt oxide nanocomposites (PANI@MgCoO 2 ) as potential cathode material for rechargeable magnesium batteries (RMB) is reported. Structural characterizations confirm the presence of a thin layer of conducting polymer on the particles of the cubic oxide that enhanced the cycling life of the battery as compared to the pristine material. To develop the electrochemical performance a twofold combination of sodium and magnesium ion is employed. The 15%PANI@MgCoO 2 nanocomposites exhibited enhanced reversible capacity (103.4 – 153 mA h g ⁻¹ ) at ~ 1 V vs. Mg ²⁺ /Mg as compared to pristine material. X-ray diffraction patterns revealed a single-phase insertion/extraction reaction mechanism into/from the cubic structure. These results establish a useful methodology for employing PANI coating on other oxides with applicability in batteries.
... The structure of the as-synthesized PANI:PSS was studied using Raman spectroscopy, as shown in Fig. 8c. Five typical Raman bands were observed at 1182, 1248, 1333, 1408, and 1601 cm -1 , which can be attributed to the C-H vibrations of the aromatic ring [50], C-N •+ vibrations of the semiquinone radicals [51], carrier vibrations of the C-N •+ polaronic structures [50], and C]C stretching vibrations of the quinoid ring [52], respectively. These results confirm that PANI:PSS was successfully synthesized in our work. ...
... The structure of the as-synthesized PANI:PSS was studied using Raman spectroscopy, as shown in Fig. 8c. Five typical Raman bands were observed at 1182, 1248, 1333, 1408, and 1601 cm -1 , which can be attributed to the C-H vibrations of the aromatic ring [50], C-N •+ vibrations of the semiquinone radicals [51], carrier vibrations of the C-N •+ polaronic structures [50], and C]C stretching vibrations of the quinoid ring [52], respectively. These results confirm that PANI:PSS was successfully synthesized in our work. ...
In this study, WO 3 nanoparticles and MoO 3 nanoribbons were prepared using a microwave-assisted hy-drothermal method. Following a grinding treatment, a stable WO 3 /MoO 3 suspension having a nanoheter-ojunction structure was obtained. Moreover, oxygen vacancies were introduced in the MoO 3 nanoribbons (MoO x) during the grinding process. Consequently, the ground WO 3 /MoO x composite film exhibited an enhanced electrochromic (EC) performance compared to the ground WO 3 and MoO 3 films not only due to its favorable morphology for ion transport but also the enhanced intervalence electron transfer. To further evaluate the potential of ground WO 3 /MoO x electrodes for practical applications, a complementary elec-trochromic device (ECD) was constructed using ground WO 3 /MoO x and polyaniline:poly(4-styr-enesulfonate) (PANI:PSS) as cathodic and anodic coloring materials, respectively. This complementary ECD yielded a transmittance modulation of 55.4% at 650 nm with rapid switching times of 7.4 s (bleaching) and 3.6 s (coloring). The ECD also exhibited a high coloration efficiency of 154 cm 2 /C and a high cycling stability with an 80.6% transmittance retention after 2000 cycles. These results demonstrate that ground WO 3 /MoO x composites are attractive materials for fabricating high-performance ECDs.
... These bands not only demonstrate the coexistence of quinoid and benzenoid structures in PANI but also illustrate the conjugated structure caused by the re-arrangement of electron clouds [33,34]. Meanwhile, the peak at 1408 cm -1 cannot be neglected, which usually appears in PANI powders with lower electrical conductivity [35]. As a result, this characteristic peak can be used as an indicator for determining the electrical conductivity of samples; due to the lack of corresponding peaks, PANI-CCl 4 , PANI-MB, and PANI-DSMO are regarded as the products with higher conductivity, which is consistent with results shown in TE test. ...
In the face of the growing energy crisis and demand on environmental protection, organic thermoelectric (TE) materials have been coming under the spotlight from global researchers as a potential countermeasure. However, there have been few studies on the relationship between the morphology of conductive polymers (CPs) and their TE performance. In this work, nanostructured polyaniline (PANI) was synthesized by interfacial polymerization with the addition of organic solvents of different polarities, including cyclohexane (CYH), carbon tetrachloride (CCl4), toluene (MB), dichloromethane (DCM), and dimethyl sulfoxide (DMSO). Physical mixing PANI with single-walled carbon nanotubes (SWCNTs) affords PANI/SWCNT composites. The composite of PANI nanobelts and 10 wt% SWCNTs achieves a power factor (PF) of 5.13 ± 0.56 μW m-1 K-2 at room temperature (RT). Spherical PANI doped with 50 wt% SWCNTs followed by pressing affords maximal room temperature PF value of 178.10 ± 3.77 μW m-1 K-2. A prototype TE generator (TEG) constructed with seven pairs of legs of as-prepared PANI/SWCNT composites and their n-type counterparts generates voltage of 10.27 ± 0.15 mV and output power of 36.65 ± 1.18 nW at temperature difference of about 50°C. This work illustrates that well-regulated PANI nanostructure could significantly affect the TE properties of PANI/SWCNT composites, which are promising in future preparation of high-performance polymer-based composites regarding the fabrication of TE devices suitable for harnessing low-grade waste heat.
