Fig 3 - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
Source publication
In present investigations polyaniline matrix was synthesized by oxidative polymerization (chemically synthesized). The polyaniline matrix was prepared on Si- substrate. The active layer of PANI as a sensor was fabricated with the help of spin-coating technique. The structural insight into the synthesized polyaniline matrix was sought by Fourier Tra...
Context in source publication
Context 1
... UV -Visible absorption spectrum of the synthesized PANI matrix at room temperature is shown in Fig. 3. The peak at 300 nm corresponds to the -* transition of the benzenoid ring, while the sharp trough at 440 nm can be assigned to the localized polaron which are characteristics of the protonated Polyaniline, together with extended tail nearly at 720 nm representing the conducting ES state of Polyaniline. This confirms the formation of ...
Similar publications
Free-standing TiO2–SiO2/polyaniline (TS/PANI) composite nanofibers were prepared by electrospinning, in situ polymerization and calcination method. The effect of tetra-n-butyl titanate (TBT) in the electrospinning solution on the morphology and the ammonia sensing properties of TS/PANI composite nanofibers were investigated. The obtained nanofibers...
Citations
... The absorption peaks at 562 cm −1 , 678 cm −1 , 798 cm −1 , and 1116 cm −1 in the spectrum of PANI are ascribed to C-S stretching vibrations, stretching deformation of the aromatic ring, the bending vibrations of aromatic -C-H, the -S-O stretching vibrations of -SO 3 group, respectively (Luo et al. 2012;Kabiri and Namazi 2016;Meriga et al. 2015;Sharma and Sharma 2013). The stretching vibrations of the protonated nitrogen present in the quinoid rings of PANI chain are observed the peak at 1297 cm −1 and the vibrational band at 1384 cm −1 is ascribed to the C-N stretching vibrations (Luo et al. 2012;Bavane et al. 2010). The vibrational peaks at 1472 cm −1 and 1555 cm −1 can be related to the C = C stretching of benzoid and quinoid rings, respectively (Solonaru and Grigoras 2017;Sultana et al. 2017;Hayatgheib et al. 2018). ...
The present study focuses on the protection of aluminium against corrosion using epoxy resin composites. The work involves chemical oxidative polymerisation of polyaniline (PANI) doped with organic acid and in situ preparation of its hybrid with silica gel (SiG) in epoxy matrix. The fillers were characterised using FTIR spectroscopy, thermogravimetric analysis, scanning electron microscopy and X-ray diffraction spectrometry. The electrochemical reversibility and stability of PANI and PANI–SiG hybrid were investigated using cyclic voltammetry. The corrosion resistance of aluminium sheet coated with the PANI-based epoxy composites was evaluated in 3.5% NaCl solution by Tafel extrapolation measurements. The corrosion parameters obtained from Tafel plots showed that the introduction of PANI considerably improved anticorrosive property of epoxy resin. There was an increase in corrosion potential from − 0.732 V to − 0.623 V and − 0.588 V and a decrease in corrosion current from 11.800 μA to 1.973 μA. The PANI–SiG hybrid further reduced the corrosion current to 0.212 μA. The penetration rates decreased from 0.064 mm/yr to 0.006 mm/yr and 0.001 mm/yr for Aluminium coated with PANI and PANI–SiG composites, respectively. The corrosion protection efficiency of the coating containing PANI–SiG hybrid was found to have a sevenfold improvement, i.e. from 13.8% of the neat resin to 98.2%.
... The lowest response from a PANI nanowire was 1.3 at room temperature for a concentration of NH 3 as high as 6400 ppm [113]. In the range of 20-1000 ppm, the majority of PANI sensors with a variety of architectures, including film, [68][69][70][71]75,107,114,115] thin film, [72][73][74], nanofibrous thin film, [116][117][118] nanofibers [108,[119][120][121], nanowire [122] and pellet [123] acquired response values below 100. But at ambient temperature, a PANI thin film with considerable flexibility showed a maximum response of 148.45 to 1000 ppm of NH 3 . ...
... In addition, research shows that the time it takes for a reaction to complete and for the system to recover can be influenced by the carrier gas used. Although it was claimed that utilizing ambient air would yield better results, the author found that using nitrogen as a carrier gas dramatically lengthened the reaction and recovery times [114]. For this reason, it would be beneficial to learn more about how different carrier gases affect reaction and recovery times. ...
To maintain human and environmental health, it is essential to detect toxic gases. Over the years, researchers have often focused on industrial waste gases like CO, NO2, H2S, and NH3. These hazardous gases can be detected by gas sensors.The conducting polymer, which has shown tremendous promise in room-temperature chemical gas detection due to the fact that its electrical conductivity may change when exposed to oxidative or reductive gas molecules, is one promising material for this sensor. Although in some circumstances, the decreased conductivity and significant attraction to volatile organic compounds and water molecules restrict sensitivity, stability, and gas selectivity, making them unsuitable for use as gas sensors. Inorganic sensitive materials provide various advantages in gas sensors, such as high sensitivity, rapid response to low-concentration analytes, a vast surface area, and changeable surface chemistry, which may supplement the sensing capabilities of conducting polymers. Along with their synergistic effects, there is a great deal of interest in combining inorganic sensitive materials with polymers for gas detection. This review focuses on the development of composite conducting polymers as gas-sensing materials. The implications of several factors affecting sensor performance, such as responsiveness, gas concentration, reaction time, and recovery time of conducting polymers, are highlighted. The function of inorganic nanomaterials in enhancing the gas-sensing performance of conducting polymers is discussed, as well as the development of conducting-inorganic composites including metal oxides, metal, and (carbon nanotube, and graphene. A comprehensive outlook on the topic of gas sensors containing conducting polymer-inorganic composites is delivered.
... The absorption peaks of PANI at 555, 666, 792 and 1074 cm −1 could be attributed to C-S stretching vibrational mode, stretching deformation of the aromatic ring, aromatic C-H bending for the substituted aromatic ring, stretching of the SO 3 -group, respectively [4,[21][22][23]. The peak at 1280 and 1392 cm −1 could be attributed to protonation of imine nitrogen atoms of quinoid rings and C N stretching of the secondary aromatic amine [4,24]. The important PANI peaks due to C C ring stretching vibration of benzoid and quinoid structures could be found at 1486 and 1603 cm -1 , respectively [5,25,26]. ...
Para-Toluene sulfonic acid doped polyaniline (PANI), PANI/chitosan composites,PANI/reduced graphene-oxide composites and a ternary composite comprising of PANI,chitosan and reduced graphene-oxide have synthesised via oxidative polymerisation ofaniline by Ammonium peroxydisulfate (APS). FTIR, XRD, FESEM and UV-VIS techniqueswere performed for the confirmation of the successful synthesis. The fundamental opticalparameters such as, complex refractive index, complex dielectric constants and opticalconductivity of the PANI and the composites were investigated in the UV-VIS-NIR range.The results show a clear dependence on the constituent component such as sulphur aswell as the absorbance values of the polymers. This study would therefore serve as initialsolution to the scarcity of studies on the optical contants of p-toluene sulfonic acid dopedpolyaniline and its composites that could have many potential electrical, optical andoptoelectronic applications.
... The FTIR spectra of PANI, PANI/chitosan, PANI/RGO, and ternary composites are shown in Fig. 1 [42,[66][67][68]. The peak at 1280 and 1392 cm −1 could be attributed to protonation of imine nitrogen atoms of quinoid rings and CeN stretching of the secondary aromatic amine [42,69]. The important PANI peaks due to C]C ring stretching vibration of benzoid and quinoid structures could be found at 1486 and 1603 cm −1 , respectively [70,71]. ...
A ternary composite comprising of p-toluene sulfonic acid doped polyaniline (PANI), chitosan and reduced graphene oxide (RGO) with stable aqueous dispersibility has been synthesised via oxidative polymerisation of aniline in chitosan/RGO dispersion. For comparison; PANI, PANI/chitosan and PANI/RGO composites were also synthesised using the same procedure. FTIR, Raman, XPS, XRD and UV-VIS confirmed the successful synthesis of the PANI and the composites. The aqueous dispersions of the PANI/chitosan and the ternary composites were found to be stable even after more than four months. The stability of the dispersion was attributed to the polycationic nature of the chitosan. The thermogravimetric analysis (TGA) shows an improved thermal stability for the ternary composite compared to PANI, PANI/chitosan and PANI/RGO composites up to about 160 °C. In addition, the electrical conductivity of the ternary composite is around 33 and 2.6 times greater than that of PANI/chitosan composite and PANI, respectively. Interestingly, the analysis of the band gap shows the lowest value of optical band gap of 2.25 eV for the ternary composite compared to PANI, PANI/chitosan and PANI/RGO with 2.50 eV, 2.60 eV and 2.44 eV, respectively. The reduced band gap for the ternary composite might be attributed to the formation of conductive networks throughout the chitosan matrix due to uniform dispersion of RGO in the chitosan matrices as well as the possible grafting of PANI onto chitosan backbone. These observed properties indicate the potential utilisation of the ternary composite in optical, electrical, optoelectronic and many other industrial applications. Keywords: Ternary composite, Doped polyaniline, Optical band gap, Chitosan, Reduced graphene-oxide
... Polyaniline (PANI) is one of the many interesting conducting polymers for gas sensing due to its different sensitivities towards multiple gases (NH3, CO, H2, NO2, methanol, H2S, hydrazine, etc.) [5,6,[8][9][10][11][12][13][14][15]. The intrinsic redox and acid/base reactions it can undergo result in different electrical properties that vary easily with doping, making it suitable for gas sensing applications [6,11,[16][17][18][19]. PANI can be doped with several acids and these dopants influence the conductivity by changing the electrical, chemical, and structural nature of polymer resulting in active gas sensing sites [20,21]. ...
... In addition to polyaniline-metal oxide hybrids, polyaniline-carbon nanotube [38,39] and polyaniline-graphene [40] composites have also been explored for gas sensing applications and have shown improved activity, owing to synergism of the materials compared to individual counterparts. Characterization of polyaniline gas sensors has been performed in several different ways: measuring the change in the surface resistivity [29,34,36,41], current-voltage plots [10,18,28,32,42], and spectroscopy [17]. Among all above-mentioned techniques, measuring the surface resistivity is one of the most facile techniques and has been employed for this study. ...
... Doped and undoped forms of polyaniline have characteristic absorption bands in the UV-Visible region. Undoped polyaniline exhibits two unique absorption bands, shown in Figure 3a, one at 640 nm due to the benzenoid to quinoid transition and a second one at 320 nm due to Π-Π * transitions from phenyl rings [17,18,22,29,46,47]. In our previous report [22] we have discussed at a greater length the occurrences of new absorption bands upon incorporation of tannin and metal oxide into polyaniline. ...
A highly active tannin doped polyaniline-TiO2 composite ammonia gas sensor was developed and the mechanism behind the gas sensing activity was reported for the first time. A tanninsulfonic acid doped polyaniline (TANIPANI)-titanium dioxide nanocomposite was synthesized by an in situ polymerization of aniline in the presence of tanninsulfonic acid and titanium dioxide nanoparticles. X-ray diffraction and thermogravimetric analysis were utilized to determine the incorporation of TiO2 in TANIPANI matrix. UV-Visible and infrared spectroscopy studies provided information about the electronic interactions among tannin, polyaniline, and TiO2. Scanning electron microscopy (SEM) along with energy dispersive X-ray spectroscopy (EDS) and atomic force microscopy (AFM) surface analysis techniques were used to investigate the metal oxide dispersions inside polyaniline matrix. Gas sensors were prepared by spin coating solutions of TANIPANI-TiO2 and TANIPANI composites onto glass slides. Sensors were tested at three different concentrations (20 ppm, 40 ppm, and 60 ppm) of ammonia gas at ambient temperature conditions by measuring the changes in surface resistivity of the films with respect to time. Ammonia gas sensing plots are presented showing the response values, response times and recovery times. The TANIPANI-TiO2 composite exhibited better response and shorter recovery times when compared to TANIPANI control and other polyaniline composites that have been reported in the literature. For the first time a proposed mechanism of gas sensing basing on the polaron band localization and its effects on the gas sensing behavior of polyaniline are reported.
... Pure PANI did show a marked variation in the current on exposure to NH 3 and its resistance increases sharply due to the deprotonation process of PANI (figure 6(b)). Deprotonation process reduces the PANI from emeraldine salt state to the emeraldine base state (Bavane et al 2010). The response curve for bare PANI pellet on exposure to 300 ppm of NH 3 is shown in figure 7. ...
Zinc oxide/polyaniline (ZnO/PANI) hybrid structures have been investigated for their optical and gas sensing properties. ZnO nanoparticles, prepared by the sol–gel method, pressed in the form of pellets were used for gas sensing. The hybrid ZnO/PANI structure was obtained by the addition of PANI on the surface of ZnO. The UV–Vis absorption of the modified pellets show band edge at 363 nm corresponding to ZnO, while a change in the absorption peaks for PANI was observed. The possible interaction between Zn2 + of ZnO and NH-group of PANI was confirmed using Raman spectroscopy studies. The results reveal that the hybrid structures exhibit much higher sensitivity to NH
$_{{3}}$
gas at room temperature than blank ZnO, which is sensitive to NH3 gas at higher temperature. This enhancement has been attributed to the creation of active sites on the ZnO surface due to the presence of PANI.
... Pawar et al. [24] studied growth and NH 3 sensing characteristics of chemically synthesized polyaniline thin films, the response value obtained for 25 ppm NH 3 is 14 with response time of 2 min. In a recent report on polyaniline based NH 3 sensor, results are given for NH 3 concentration ranging from 100 to 500 ppm with a response value of 2.5 for 100 ppm NH 3 and an approximate response time of 10 min [25]. Saxena et al. [26] demonstrated a room temperature operated NH 3 sensor based on polycarbazole film deposited using Langmuir-Blodgett technique; the response was studied in range of 200-5000 ppm NH 3 with response value 3 for 200 ppm. ...
... Interestingly in our results, gas response value obtained is 16 for 25 ppm NH 3 at room temperature, higher than other reported values for similar concentration of NH 3 . Further, the response time for our sensor is 20 s and recovers fully to base value in 15 min which indicates rapid detection of NH 3 as compared to previously reported response-recovery profile of polyaniline based NH 3 sensors [24,25]. Moreover, present sensor exhibits detectability towards 4 ppm NH 3 which is sufficiently lower than toxic limit of NH 3 . ...
Polypyrrole thin films were synthesized in situ by chemical polymerization. Fourier transform infrared spectroscopy revealed formation of polypyrrole. The morphological studies by scanning electron microscopy showed formation of uniform granular structure with average grain size of 0.6μm. The film composition was characterized by X-ray photoelectron spectroscopy for chemical composition in polypyrrole film. These films were investigated for their sensing behaviour towards NH3 and NO at room temperature. It has been observed that these films are selective for NH3 and the sensitivity exhibited a linear response in range of 4–80ppm.
The intensive investigation of supercapacitors and other advanced energy storage technologies has been driven by the growing demand for portable electronic devices, electrical equipment, and hybrid electric vehicles in the transportation sector. To develop these systems, it is crucial to have electrodes capable of high energy storage, along with suitable electrolytes to facilitate ion transport or conduction. These energy storage devices, which incorporate nanostructured and compact electrodes, exhibit excellent electrochemical performance. The hybrid nanostructured composites made of carbon allotropes and conducting polymers have received much attention recently due to their possible use in supercapacitors. They are perfect candidates for energy storage applications because of their high electrical conductivity, mechanical strength, and stability. We synthesized reduced graphene oxide by a modified Hummer’s method and composited it with aniline monomers by in situ chemical polymerization to fabricate nanostructured composites of polyaniline and graphene. The different samples were synthesized by varying their mass ratios followed by their characterization by different characterization techniques such as XRD, FTIR, Raman, FESEM, and cyclic voltammetry, etc.
Organic acid doped polyaniline (PANI), hybrid with silica gel (SiG) and composites with metal primer have been prepared by chemical oxidative polymerization of double-distilled aniline in an acidic medium at 0-5 °C in an ice bath using ammonium persulphate as oxidant and p -toluene sulphonic acid (p-TSA) as the dopant. The anticorrosive property of PANI coatings containing alkyd primer, zinc chromate and silica gel was investigated. The coatings were characterized by FTIR spectroscopy, scanning electron microscopy and electrochemical impedance spectroscopy. The corrosion studies were carried out in a 3.5 wt% NaCl solution. On introduction of SiG, PANI, and PANI-SiG hybrid, the corrosion current decreased from 0.03626 μA to 0.007856 μA, 0.02042 μA, and 0.011 μA, respectively. The penetration rates calculated in mm/yr. for the composites: SiG/Primer, PANI/Primer and PANI-SiG/Primer were 0.430× 10 ⁻⁴ , 1.110× 10 -4, and 0.599 × 10 -4, respectively and that of neat primer was 1.977 × 10 ⁻⁴ . The corrosion protection efficiency of the primer was improved up to 7% on introduction of the PANI-based fillers. The 5 wt% of 1:1 PANI-SiG/primer composite, which contains 2.5wt% of PANI, showed better results than that of 5wt% PANI in Primer and these results are very close to that of 5wt% SiG/Primer composites.
We report novel application of cetryltrimethylammonium bromide (CTAB) assisted polyaniline (PAN) nanostructures to fabricate cost effective chemiresistive sensor for monitoring of low ppm level of sulphur dioxide (SO2) at room temperature. PAN nanoparticles (NPs, diameter ~200 nm), nanofibres (NFs, diameter ~100 nm) and nanoneedles (NNs, diameter ~50 nm) were synthesized via template directed chemical oxidative polymerisation of aniline by varying the concentration of solitary cationic surfactant, CTAB (from 5 mM to 15mM). It is observed that PAN NNs based sensing device showed excellent sensing response (~4.2%) towards low concentration of SO2 (10 ppm), as compared to device based on PAN NFs (~3%) and PAN NPs (~1.2%) at room temperature. PAN NNs based sensing device has been also found to be efficient in terms of stability, selectivity, reproducibility, recovery and response time, and detection range. The mechanism of SO2 sensing has been explored for the first time in light of in-situ Fourier transform infrared (FTIR) spectroscopy.
