Polyaniline Emeraldine Base Research Articles

Characterization of Luffa-reinforced Polyaniline Films

Herein, Polyaniline (PANI)/polyethylene oxide (PEO) - luffa cylindrica bio-composite films of various mass fractions (%) have been prepared via casting solution of emeraldine base polyaniline and cellulose extracted from luffa. The biopolymer films were structurally and thermally characterized using X-ray diffraction (XRD), Fournier Transform-InfraRed (FT-IR) spectroscopy, and differential scanning calorimetry analysis (DSC). Moreover, the electrical properties of conductive biopolymer solutions were measured by using the conductivity meter. According to the obtained results, treated luffa increases the conductivity of biopolymers. XRD results reveal that luffa increases the crystallinity of bio-composite films in comparison to PANI/PEO films. FTIR analysis proved the presence of functional groups of PANI, PEO, and luffa in the film structure. Also, an increase in the weight of luffa in the bio-composite film brings about an increase in the peak intensities of the O-H group. It is determined that luffa enhances the thermal stability of composites via the results of DSC analysis.

Investigating the electronic properties and reactivity of polyaniline emeraldine base functionalized with metal oxides

Due to its appealing qualities, such as its miniature size and the ability to modify physical properties through chemical synthesis and molecular design, polymer material offers considerable advantages over traditional inorganic material-based electronics. Conjugate polymers are particularly interesting because of their molecular design capabilities, which enable the synthesis of conducting polymers with a variety of ionization potentials and electron affinities (EA), and their ability to control the energy gap and electronegativity (χ). Accordingly, density functional theory (DFT) at the B3LYP/SDD model was used to present possible interactions between polyaniline (PANi) and both alkali and heavy metal oxides. Total dipole moment (TDM), HOMO–LUMO band gap energy (ΔE), ionization energy (IE), EA, chemical hardness (η), chemical potential (μ), electrophilicity index (ω), chemical softness (S), and χ are calculated. TDM of PANi increased while ΔE decreased due to functionalization. The distribution of electronic charge density in molecular electrostatic potential (MESP) maps together with the results of ω reflected the electrophilic nature. The obtained results confirmed that the addition of metal oxides significantly improves the TDM, ΔE, and reactivity descriptors. A strong correlation between the experimental and calculated IR spectra was observed. Additionally, PANi–2MgO and PANi–2MnO model molecules exhibited the highest reactivity. Accordingly, PANi functionalized with MgO and MnO are promising candidates for energy storage devices.

Ceramic Nanotubes—Conducting Polymer Assemblies with Potential Application as Chemosensors for Breath Ammonia Detection in Chronic Kidney Disease

This paper describes the process of producing chemosensors based on hybrid nanostructures obtained from Al2O3, as well as ZnO ceramic nanotubes and the following conducting polymers: poly(3-hexylthiophene), polyaniline emeraldine-base (PANI-EB), and poly(3, 4-ethylenedioxythiophene)-polystyrene sulfonate. The process for creating ceramic nanotubes involves three steps: creating polymer fiber nets using poly(methyl methacrylate), depositing ceramic films onto the nanofiber nets using magnetron deposition, and heating the nanotubes to 600 °C to burn off the polymer support completely. The technology for obtaining hybrid nanostructures from ceramic nanotubes and conducting polymers is drop-casting. AFM analysis emphasized a higher roughness, mainly in the case of PANI-EB, for both nanotube types, with a much larger grain size dimension of over 5 μm. The values of the parameter Rku were close or slightly above 3, indicating, in all cases, the formation of layers predominantly characterized by peaks and not by depressions, with a Gaussian distribution. An ink-jet printer was used to generate chemiresistors from ceramic nanotubes and PANI-EB structures, and the metallization was made with commercial copper ink for printed electronics. Calibration curves were experimentally generated for both sensing structures across a wider range of NH3 concentrations in air, reaching up to 5 ppm. A 0.5 ppm detection limit was established. The curve for the ZnO:PANI-EB structure presented high linearity and lower resistance values. The sensor could be used in medical diagnosis for the analysis of breath ammonia and biomarkers for predicting CKD in stages higher than 1. The threshold value of 1 ppm represents a feasible value for the presented sensor, which can be defined as a simple, low-value and robust device for individual use, beneficial at the patient level.

FeCo/PANI composites as electromagnetic shields in the X-band: An understanding of the loss mechanisms

The growing dependence on electronic devices functioning within the microwave frequency range, coupled with the need for miniaturization, has resulted in increased instances of electromagnetic interference (EMI) in such devices. Besides altering device performance, the associated health hazards due to electromagnetic radiations have necessitated the urgency for developing efficient electromagnetic shielding materials. Here, highly magnetic FeCo nanoparticles, approximately 200 nm in diameter, have been used as magnetic filler materials in emeraldine base (PANI – EB) and emeraldine salt (PANI – ES) forms of polyaniline to understand the EMI shielding response in X-band frequency range (8.2–12.4 GHz). Composites using 10 % and 25 % FeCo by weight have been prepared using a physical mixing approach and uniform dispersion within the polymer matrix is ascertained using FE-SEM imaging and EDX elemental maps. Structural and magnetic properties of FeCo remain unaltered after the grind mixing process, as confirmed by XRD and VSM measurements. With the total shielding effectiveness remaining sufficiently low at 2–3 dB in FeCo/PANI – EB, significant enhancement to up to 40 dB is achieved in composites prepared in PANI – ES. Detailed investigations of electromagnetic parameters of the composites reveal the importance of the magnetic filler to achieve an absorption-dominated shielding of electromagnetic waves.

Engineering Carbon Nanotube Yarns with Polyaniline Coating toward Enhanced Thermoelectric Performance.

The growing demand for wearable electronics has driven the development of flexible thermoelectric (TE) generators which can harvest waste body heat as a renewable power source. Despite carbon nanotube (CNT) yarns have attracted significant attention as a promising candidate for TE materials, challenges still exist in improving their TE efficiency for commercial applications. Herein, we developed high performance CNT/polyaniline (PANI) yarns by engineering the coating of polyaniline emeraldine base (PANIeb), in which CNT yarns were firstly coated by PANIeb layer and further doped by HCl vapor treatment. With the incorporation of PANIeb, σ and S were simultaneously increased to 1796 S cm-1 and 74.8 μV K-1 for CNT/PANIeb 4-2d fibers, respectively. Further HCl vapor treatment induced greatly increased σ to 3194 S cm-1, but maintained be 83 % value before doping, giving rise to the highest power factor of 1224 μW m-1K-2, higher than pristine CNT yarns of 576 μW m-1K-2. Combining outstanding high TE performance and bending durability, a flexible TE generator was constructed to deliver high out power of 187 nW with temperature gradients of about 30 K. These results demonstrate the potential promise of high-performance CNT/PANI-HCl yarns to harvest waste body heat for sustainable power supply.

The influence of anions in the ionic liquid-water mixtures on the conformational structures of emeraldine base and emeraldine salt form of polyaniline

The development of antifouling membranes for water filtration applications is challenging. Conducting polymers can show enhanced antifouling characteristics by blending with various polymers, nanomaterials, and Ionic liquids (ILs). In this paper, we perform an all-atom molecular dynamics simulation on a conducting polymer polyaniline (PANI) immersed in IL-water mixtures. Two forms of PANI were considered, namely Emeraldine base (EB) and Emeraldine salt (ES) as well as two different water-mixed ILs are considered namely (a) 1-ethyl-3-methyl imidazolium [EMIM]+ hexafluorophosphate [PF6]- and (b) 1-ethyl-3-methyl imidazolium [EMIM]+ tetra-fluoroborate [BF4]-. We present various intra- and inter-molecular structural properties, solvation thermodynamics, and dynamic properties. We observe that with an increase in IL concentration, the radius of gyration (Rg) value shows a decrease for ES in pure state in both ILs; on the other hand, we see a minimal increase in the Rg values of EB in both ILs. The dihedral angle distribution analysis shows a combination of gauche and trans state for ES, whereas trans state is more pronounced for the case of EB in both water-IL mixtures. The radial distribution function (RDF) analysis between the ortho, meta carbons of the benzene rings, and the amine groups on ES with [BF4]- and [PF6]- show significant structural peaks. On the other hand, EB and ES show lower interaction with the water molecules. The number of hydrogen bonds (h-bonds) between polymer and water is higher for EB than ES in both IL-water mixtures. The hydrogen bond lifetime (τ) values show one-fold higher values for EB than ES. The self-diffusion coefficient (D) values of water show a decrease with an increase in IL concentration. The thermodynamic properties solvation enthalpy (ΔH) and excess molar volume (VmE) for both ES and EB show a more favorable solvation in [EMIM]+[BF4]- when compared to [EMIM]+[PF6]- with an increase in IL concentration. These observations are crucial for selecting ILs and designing sustainable polymers for antifouling membranes.

Construction of novel coaxial electrospun polyetherimide@polyaniline core-shell fibrous membranes as free-standing flexible electrodes for supercapacitors

Designing porous and flexible electrodes with excellent electrochemical properties is crucial to fabricate high-performance flexible supercapacitors. Conductive polymer-based electrospun fibers are expected to be an ideal material for constructing flexible electrodes due to the enormous specific surface area, unique pore structure and inherent flexibility. However, the exploration of such electrospun fibers with facile preparation methods and high areal capacitance remains challenging. Herein, a novel polyetherimide@polyaniline core-shell fibrous membranes (PEI@PANI CFMs) is fabricated via simply coaxial electrospinning and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) secondary doping. With the aid of polyetherimide, highly concentrated emeraldine base polyaniline (EB-PANI) can be perfectly wrapped on the surface of fibers without any spinning assistants, ensuring the well-developed pore structures, superior hydrophilicity, good electrical conductivity and outstanding mechanical flexibility. Benefiting from the synergistic effect of structure and constituents, such flexible PEI@PANI CFMs as electrode materials can provide more accessible electrochemical active sites and decrease the ion diffusion resistance. Therefore, the PEI@PANI CFMs present outstanding areal capacitance of 1159.9 mF cm−2 and remarkable energy density of 46.91 μW h cm−2 in the electrodes and symmetric supercapacitors, demonstrating great potential for applications in flexible energy storage field. This fabrication strategy provides a simple and practicable way to manufacture polyaniline-based fibrous membranes for high-performance flexible electrode materials.

A polyaniline/polyvinyl acetate composite film electrode for highly sensitive electrochemical sensing of pH

The electrochemical performances of three types of polyaniline (PANI)-based films developed as pH-sensing electrodes were evaluated and compared. PANI emeraldine base (PANI-EB), PANI emeraldine salt (PANI-ES), and PANI-ES/polyvinyl acetate (PVAc) composite films were spin coated on fluorine-doped tin oxide (FTO) glass substrates to fabricate pH-sensing electrodes. The surface morphology, wetting properties, and electrochemical properties were characterized and compared. Unprotonated PANI-EB films had a regular structure with residual flakes, whereas protonated PANI-ES and PANI-ES/PVAc films exhibited globular and porous structures, respectively. All PANI-based films adhered well to the FTO substrate. Water contact angles indicated the hydrophobic characteristic of the PANI-EB films and the hydrophilicity of the PANI-ES films, which could affect their stability in buffered solutions of different pH. The PANI-ES/PVAc films exhibited improved stability because of the hydrophobic PVAc. The PANI-ES/PVAc electrodes exhibited a significantly higher pH sensitivity of 100 mV pH−1 than those of the single-component PANI-EB and PANI-ES electrodes (57 and 65 mV pH−1, respectively) in the pH range of 3.0–8.0, which could be attributed to the non-equilibrium protonation/deprotonation of nitrogen atoms in the PANI structure. Moreover, the PANI-ES/PVAc electrodes also exhibited good reproducibility and selectivity to H+ over certain other ions and molecules (e.g., glucose).

On the toxicity behaviour of composite polyaniline-zinc oxide photocatalytic nanoparticles and their surrogate chemicals

The acute toxic effect of home-made polyaniline-zinc oxide (PANI-ZnO) nanocomposite photocatalyst samples was investigated. Toxicity behaviour was compared with that of their surrogates PANI-emeraldine base (PANI-EB), PANI-emeraldine salt (PANI-ES) and zinc oxide (ZnO). The freshwater crustacean Daphnia magna reacted more sensitively to the exposure than the marine photobacterium Vibrio fischeri and thus higher acute toxicity levels were recorded for Daphnia magna. The toxicity response increased with exposure time for both tested organisms. The hydrophobic PANI-EB was non-toxic, whereas ZnO nanoparticles were toxic towards both test organisms and the main reason of the toxicity of the PANI-ZnO composites. The toxicity behaviour changed with ZnO content rather than the PANI-ZnO nanocomposite synthesis type (in-situ polymerization or hybridization method). The acute toxicity also increased when the PANI-ZnO samples were subjected to UV-A (photocatalytic) treatment (conditions:0.25 g/L catalyst; pH=7.0; t = 180 min; I0 =0.5 W/L). A relationship between the photo-induced Zn(II) release and acute toxicity increase after photocatalytic treatment was evident.

Improvement of active/passive anti-corrosion/weathering properties of epoxy-siloxane structure via cloisite 30B/polyaniline inclusion as new hybrid nanocomposite coatings

Researches in the corrosion protection field have been led to various mechanisms for protecting metals in harsh media as well as several efficient anti-corrosion materials. For instance, some studies have suggested clay nanolayers as an active barrier filler for coating protected systems and others have figured out polyaniline as an anti-corrosive pigment. However, no study has thoroughly examined these two additives alongside each other and compared their mechanical, anti-corrosion and anti-weathering performances. In this study, two different mechanisms of active barrier and passive behaviors were compared through epoxy-siloxane reinforcement by divergent contents of 1–4 wt% of Cloisite 30B nanoplatelets (CN) and 0.25–1 wt% of polyaniline emeraldine base (PEB) particles. Also, the effect of CN and PEB particles on corrosion, weathering resistances, and mechanical properties of epoxy-siloxane based hybrid nanocomposite matrix was explored as novel effective/potent functional coatings applied on the mild steel substrate. In this regard, the proper dispersion of additives was characterized by XRD, optical microscopy, and HRTEM. Anti-corrosion properties of the system were assessed via EIS and salt spray examinations. According to the significant effect of mechanical properties on the protection and overall performance of coatings, they were studied through Pull-Off, DMTA, and impact tests. Q-UV test, AFM, and color spectroscopy were utilized for analyzing the weathering resistance of samples. Results indicated that 2 wt% CN and 0.75 wt% PEB has the best anti-corrosion performance as well as desirable resistance against destructive atmospheric agents. Overall, in comparison, the CN nanosheets possessed higher anti-corrosion behavior as a potent barrier function, whereas the PEB showed dominant weathering resistance via an impressive passivation feature.

Carbonization of MOF-5/Polyaniline Composites to N,O-Doped Carbon/ZnO/ZnS and N,O-Doped Carbon/ZnO Composites with High Specific Capacitance, Specific Surface Area and Electrical Conductivity.

Composites of carbons with metal oxides and metal sulfides have attracted a lot of interest as materials for energy conversion and storage applications. Herein, we report on novel N,O-doped carbon/ZnO/ZnS and N,O-doped carbon/ZnO composites (generally named C-(MOF-5/PANI)), synthesized by the carbonization of metal-organic framework MOF-5/polyaniline (PANI) composites. The produced C-(MOF-5/PANI)s are comprehensively characterized in terms of composition, molecular and crystalline structure, morphology, electrical conductivity, surface area, and electrochemical behavior. The composition and properties of C-(MOF-5/PANI) composites are dictated by the composition of MOF-5/PANI precursors and the form of PANI (conducting emeraldine salt (ES) or nonconducting emeraldine base). The ZnS phase is formed only with the PANI-ES form due to S-containing counter-ions. XRPD revealed that ZnO and ZnS existed as pure wurtzite crystalline phases. PANI and MOF-5 acted synergistically to produce C-(MOF-5/PANI)s with high SBET (up to 609 m2 g-1), electrical conductivity (up to 0.24 S cm-1), and specific capacitance, Cspec, (up to 238.2 F g-1 at 10 mV s-1). Values of Cspec commensurated with N content in C-(MOF-5/PANI) composites (1-10 wt.%) and overcame Cspec of carbonized individual components PANI and MOF-5. By acid etching treatment of C-(MOF-5/PANI), SBET and Cspec increased to 1148 m2 g-1 and 341 F g-1, respectively. The developed composites represent promising electrode materials for supercapacitors.

Electrochemical properties of aluminum ion batteries with emeraldine base polyaniline as cathode material

Aluminum ion batteries (AIBs) are currently attracting widespread interest due to their high capacity, low price and high safety, while practical applications are severely hampered by the lack of suitable cathodes and the relatively complex and divergent energy storage mechanisms. Polyaniline has shown considerable promise for application in various rechargeable batteries, however, little research has been conducted on the application to AIBs. Here, the emeraldine base polyaniline (PANI) using a chemical oxidation method is synthesized and then assembled in an Al/PANI cell with a chloroaluminate ionic liquid as the electrolyte. Compared with the conventional protonated polyaniline cathode, the PANI cathode shows better electrochemical performance during the 0–2.4 V charging/discharging process, exhibiting a discharge specific capacity of 155 mAh g-1 at a current density of 1 A g -1and capacity retention of 80% after 2000 cycles. Meanwhile, ex-situ characterization reveals a novel conversion process of this system different from that of conventional proton-doped polyaniline materials, in which the electrolyte is spontaneously complexed with the PANI cathode. This is followed by reversible doping of the chloroaluminate anion in the –NH- group of the PANI-AlCl3 complex, yielding high reversible capacity and long cycle life. These findings have made new attempts and laid the foundation for the development of high-performance aluminum ion batteries with conducting polymers as the cathode material and further clarification of their charge storage and reaction mechanisms.

Physicochemical effects of proton implantation doping on transparent nanoscale thin films of polyaniline emeraldine base covalently fabricated on organosilanized surfaces

Physicochemical effects of proton implantation doping on transparent nanoscale thin films of non-conductive polyaniline emeraldine base covalently fabricated on organosilanized surfaces were investigated in this study. Resistance measurement using the Au-electrode array coated with an initially non-conductive thin film of polyaniline emeraldine base showed that proton irradiation could first induce a drastic effect to decrease the resistance of polyaniline emeraldine base and then continue to act as a doping process to further exponentially reduce the resistance to yield a relatively stable conductive state for the proton-irradiated PANI EB. Analysis of experimental results obtained by X-ray photoelectron spectroscopy and Raman spectroscopy also revealed that (i) the proportion of bonding structures characterized as protonated amine/imine groups related to electrical conduction for polyaniline was increased after proton irradiation, (ii) nitro groups were introduced to the polymer by the applied proton beam propagating through the ambient air and (iii) crosslinking could be induced by proton irradiation through the formation of phenazine-like structures between polymer chains. With crosslinking and nitration, the proton-irradiated polyaniline exhibited electrical conductivity similar to that of polyaniline derivatives with N-alkylaniline and nitroaniline as co-monomer units in the polymer chains.

Atmospheric pressure plasma jet treatment of PLA/PAni solutions: Enhanced morphology, improved yield of electrospun nanofibers and concomitant doping behaviour

To obtain uniform and bead-free nanofibers by means of electrospinning is sometimes very challenging, especially for polymers with low solubility, such as for example the intrinsically conducting polymers (ICPs). Recently, atmospheric pressure plasma jet (APPJ) treatment to pre-electrospinning polymer solutions has been found to effectively enhance the electrospinnability of a single polymer type. Here, such an APPJ treatment has been applied for the first time to a blended polymeric solution consisting of polylactic acid (PLA) and polyaniline emeraldine base (PAni EB) as well as its emeraldine salt (ES) form doped by camphorsulfonic acid (CSA). The plasma-induced physical changes of the solutions including pH, conductivity, viscosity and surface tension have been investigated and correlated with the ensuing physicochemical properties of the electrospun nanofibers. To do so, next to the liquid-based characterizations, the nanofibers have been examined by means of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), water contact angle (WCA) goniometry and uniaxial tensile testing. Results revealed that the pre-electrospinning plasma modification step resulted in a remarkably enhanced nanofiber morphology, deposition yield and mechanical performance of the electrospun nanofibers. Moreover, concomitant doping of PAni EB to PAni ES, as an unexpected side behaviour generated during the plasma treatment without the addition of any protonic acid, was found and further carefully investigated using ultraviolet/visible (UV–Vis) spectrometry. The findings obtained in this work thus enlarge the application range of pre-electrospinning APPJ treatment from single to blended polymeric solutions. Moreover, the recent pioneering discovery revealing the pre-electrospinning APPJ treatment role in enhancing electrospinning has surpassed the sole connotation of improved fiber morphology as new interesting effects are discerned in this study: boosted nanofiber deposition yield and doping capabilities.

Potentiometric pH Sensor Based on Flexible Screen-Printable Polyaniline Composite for Textile-Based Microfluidic Applications.

Skin pH can be used for monitoring infections in a healing wound, the onset of dermatitis, and hydration in sports medicine, but many challenges exist in integrating conventional sensing materials into wearable platforms. We present the development of a flexible, textile-based, screen-printed electrode system for biosensing applications, and demonstrate flexible polyaniline (PANI) composite-based potentiometric sensors on a textile substrate for real-time pH measurement. The pH response of the optimized PANI/dodecylbenzene sulfonic acid/screen-printing ink composite is compared to electropolymerized and drop-cast PANI sensors via open circuit potential measurements. High sensitivity was observed for all sensors between pH 3–10, with a composite based on PANI emeraldine base, demonstrating sufficient response time and a linear sensitivity of −27.9 mV/pH. This exceeded prior flexible screen-printed pH sensors in which all parts of the sensor, including the pH sensing material, are screen-printed. Even better sensitivity was observed for a PANI emeraldine salt composite (−42.6 mV/pH), although the response was less linear. Furthermore, the sensor was integrated into a screen-printed microfluidic channel demonstrating sample isolation during measurement for wearable, micro cloth-based analytical devices. This is the first fully screen-printed flexible PANI composite pH sensor demonstrated on a textile substrate that can additionally be integrated with textile-based microfluidic channels.

Physicochemical Properties and Atomic-Scale Interactions in Polyaniline (Emeraldine Base)/Starch Bio-Based Composites: Experimental and Computational Investigations.

The processability of conductive polymers still represents a challenge. The use of potato starch as a steric stabilizer for the preparation of stable dispersions of polyaniline (emeraldine base, EB) is described in this paper. Biocomposites are obtained by oxidative polymerization of aniline in aqueous solutions containing different ratios of aniline and starch (% w/w). PANI-EB/Starch biocomposites are subjected to structural analysis (UV-Visible, RAMAN, ATR, XRD), thermal analysis (TGA, DSC), morphological analysis (SEM, Laser Granulometry), and electrochemical analysis using cyclic voltammetry. The samples were also tested for their solubility using various organic solvents. The results showed that, with respect to starch particles, PANI/starch biocomposites exhibit an overall decrease in particles size, which improves both their aqueous dispersion and solubility in organic solvents. Although X-ray diffraction and DSC analyses indicated a loss of crystallinity in biocomposites, the cyclic voltammetry tests revealed that all PANI-EB/Starch biocomposites possess improved redox exchange properties. Finally, the weak interactions at the atomic-level interactions between amylopectin–aniline and amylopectin–PANI were disclosed by the computational studies using DFT, COSMO-RS, and AIM methods.

Polymer-metal complexes as emerging catalysts for electrochemical reduction of carbon dioxide

A class of metal-doped polyanilines (PANIs) was synthesized and investigated as electrocatalysts for the carbon dioxide reduction reaction (CO2RR). These materials show good affinity for the electrode substrate and allow to obtain stable binder-free electrodes, avoiding the utilization of expensive ionomer and additives. The emeraldine-base polyaniline (EB-PANI), in absence of metal dopant, shows negligible electrocatalytic activity and selectivity toward the CO2RR. Such behavior significantly improves once EB-PANI is doped with an appropriate cationic metal (Mn, Cu or Sn). In particular, the Sn-PANI outperforms other metal-doped samples, showing a good turnover frequency of 72.2 h−1 for the CO2RR at − 0.99 V vs the reversible hydrogen electrode and thus satisfactory activity of metal single atoms. Moreover, the Sn-PANI also displays impressive stability with a 100% retention of the CO2RR selectivity and an enhanced current density of 4.0 mA cm−2 in a 10-h test. PANI, a relatively low-cost substrate, demonstrates to be easily complexed with different metal cations and thus shows high tailorability. Complexing metal with conductive polymer represents an emerging strategy to realize active and stable metal single-atom catalysts, allowing efficient utilization of metals, especially the raw and precious ones.Graphic abstract

The Effect of pH and Monomer Concentration on Polyaniline Thin Films Grown Using Electrodeposition

Polyaniline (PANI) thin films were successfully prepared from an aqueous electrolyte bath containing aniline and sulphuric acid (H2SO4) using electrodeposition method. The present study demonstrates that the properties of PANI thin film depends on the variation of pH and aniline concentration in prepared precursor. The optical and structural of PANI thin films were characterized using UV-Visible spectrometer (UV-Vis), X-ray diffraction spectrometer (XRD), Fourier Transform Infra-Red spectrometer (FTIR) and Raman spectrometer. PANI layer grown at pH 2.00 displayed green colour layer which denoted as emeraldine base (half oxidized state of PANI) while at pH 3.80 the colour of PANI layer was yellow representing the leucoemeraldine base (fully reduced state of PANI). Result obtained from FTIR confirmed the footprint of PANI and Raman spectrometer confirmed the half oxidized emeraldine base of PANI. Optical analysis using UV-Vis demonstrated the smallest energy band gap, Eg of PANI is 3.54 eV for sample with 0.50 M aniline concentration and pH 2.00. The trend shows that the bandgap of PANI is increased as the pH increased from 2.00 to 3.80. XRD result showed that all the deposited PANI layers were amorphous. Full characterization of this material is providing some information on PANI behavior due to pH and concentration in the prepared precursor.

Comparison of Optical Characteristics of GO-PANI Composite in Solution and Thin Film

Reduced Graphene Oxide (rGO) is a promising material as an active electrodes material for supercapacitors. However, in its application, rGO can only store electrostatic charges so there is no electron transfer between surface of the electrode and electrolyte. In order to improve electrode performance, rGO can be composite with conductive polymers such Polyaniline (PANi). It was reported that rGO-PANi composite can increase conductivity of rGO and support pseudocapacitance of the material so the electron transfer can be carried out actively through reduction-oxidation (redox) reactions. In this work we study preparation of rGO-PANI composite using UV oven spraying method. Thin layers of rGO-PANi composite were prepared from mixture of 0.5 mg/ml GO dispersion (Graphenia) and PANi-HCl solution with a ratio of 1:1. PANi-HCl solution were prepared from PANi Emeraldine Base and 1 M HCl with mole ratio of 1:2. The samples were spray coated onto quartz substrates under photo-irradiation using UV Oven Spraying apparatus. In order to obtain a proper thickness for electrode application we varied deposition repetition. The optical characteristics of the rGO-PANi composites were measured using UV-Vis Spectroscopy. The results were compared with the optical spectra of rGO and PANi, respectively. Acknowledgement This work was funded by Hibah Kemenristek Dikti Indonesia, contract no: 1827/UN6.3.1/LT/2020 date 12 May 2020.

Preparation of PANI Modified ZnO Composites via Different Methods: Structural, Morphological and Photocatalytic Properties

Polyaniline modified zinc oxide (PANI-ZnO) photocatalyst composites were synthesized by focusing on dissolution disadvantage of ZnO. In-Situ chemical oxidation polymerization method was performed under neutral conditions (PANI-ES) whereas in hybridization method physical blending was applied using emeraldine base of polyaniline (PANI-EB). PANI-ZnO composites were prepared in various ratios of aniline (ANI) to ZnO as 1%, 3%, 6% and 9%. The alterations on the structural and morphological properties of PANI-ZnO composites were compared by Fourier Transform Infrared (FT-IR), Raman Spectroscopy, X-ray Diffraction (XRD) and Scanning Electron Microscopy-Energy Dispersive X-ray Analysis Unit (SEM-EDAX) techniques. FT-IR and Raman spectroscopy confirmed the presence of PANI in all composites. SEM images revealed the morphological differences of PANI-ZnO composites based on PANI presence and preparation methods. Photocatalytic performances of PANI-ZnO specimens were investigated by following the degradation of methylene blue (MB) in aqueous medium under UVA irradiation. The effects of catalyst dose and initial dye concentration were also studied. MB degradation was followed by both decolorization extents and removal of aromatic fractions. PANI-ZnO composites expressed enhanced photocatalytic performance (~95% for both methods) as compared to sole ZnO (~87%). The hybridization method was found to be more efficient than the In-Situ chemical oxidation polymerization method emphasizing the significance of the neutral medium.