Polymerization Of Aniline In Presence Research Articles

Polyaniline-(dinonylnapthyl disulphonic acid) hydrogel showing enhanced supercapacitor and photo-current performance by in situ growth of AgNPs

Emulsion polymerization of aniline in presence of dinonylnapthyl disulphonic acid (DNNDSA) produces 3D-fibrillar network and invariant storage and loss modulus with frequency suggest (PANI-DNNDSA, PD) gel formation. The x-ray diffraction and x-ray photoelectron spectroscopy confirm in-situ Ag NP formation. The PD gel exhibits excellent specific capacitance of 1100 F/g, however, in-situ growth of AgNPs (PDAg1.2) exhibits specific capacitance 1350 F/g at 1 A/g current density in three-electrode technique. Two electrode measurement with flexible carbon cloth using poly(vinyl alcohol)-H2SO4 gel electrolyte shows a specific capacitance value of 646 F/g and Ragon plot exhibits maximum power density 7000 W/kg at energy density of 34.7 Wh/kg. The PDAg1.2 gel exhibit highly improved photocurrent with simultaneous presence of photocurrent memory and photocurrent rectification which are absent in pure PD gel. Due to synergistic interaction between silver plasmon bands and polaronic bands of PANI very good photocurrent and stable photocurrent switching is noticed.

PANI/Ferrous Oxide Based Hybrid Material for Ammonia Sensing Applications

AbstractIn the present study, polyaniline (PANI) and ferrous oxide (α‐Fe2O3) are amalgamated for ammonia sensing purpose. The hybrid nanocomposite is prepared by a single step in situ chemical oxidative polymerization of aniline in presence of hydrothermally prepared α‐Fe2O3 nanoparticles. The structural and compositional analyses of the hybrid material are fully executed by FTIR, PXRD, and SEM techniques. A naive, exceedingly selective, quickly restorable, and ambient temperature functioning ammonia detecting device is established by using PANI/α‐Fe2O3. The investigation results indicate that the PANI/α‐Fe2O3 hybrid nanocomposite exhibits selective sensing ability towards ammonia vapors. The PANI/α‐Fe2O3 displays excellent response for 5 ppm and maximum response for 100 ppm of ammonia. The response time of the PANI/α‐Fe2O3 sensor is found to be quick with reasonably short recovery time. Due to excellent reusability, good environmental stability, and highly economical synthesis the PANI/α‐Fe2O3 delivers a capable, simple, and efficient sensor system for ammonia detection at ambient temperature.

HYDROTHERMALLY GROWN ZnO/rGO AND ZnO/PANI NANOHYBRIDS: COMPARATIVE STUDY ON THEIR ELECTRICAL CONDUCTANCE

The unique properties of Zinc Oxide, Graphene and their nanocomposite have enabled them to fabricate manyoptoelectronic devices which offer advantages like light weight, good stability and optical transparency. Conductingpolymer/graphene hybrids are also a major class of composite materials for the fabrication of donor/acceptor basedelectronic devices. In this paper we report the synthesis, characterization and conductivity measurements in ZnO/rGOand ZnO/PANI binary nanohybrids. ZnO nanotops are synthesized by low temperature hydrothermal method, grapheneoxide (GO) by modified Hummer’s Method, reduced graphene oxide (rGO) by hydrothermal in situ reduction techniqueand PANI from aniline by chemical polyoxidation reaction. ZnO/rGO nanohybrid is prepared by hydrothermaltreatment of ZnO and GO, whereas ZnO/PANI by in-situ oxidative polymerization of aniline in presence of ZnO. Allthe materials were characterized using SEM, TEM, XRD, UV-Vis, IR&TGA. The as-synthesized samples were dispersedin IPA, coated on quartz glass using spin-coating technique, and dark conductivity measurements were done.

Synergistically improved thermal stability and electromagnetic interference shielding effectiveness (EMI SE) of in-situ synthesized polyaniline/sulphur doped reduced graphene oxide (PANI/S-RGO) nanocomposites

Polyaniline (PANI) and its composite with sulphur doped reduced graphene oxide (S-RGO) have been successively synthesized via in-situ chemical oxidative polymerization of aniline in presence of 10 wt. % S-RGO nanosheets. Physico-chemical analyses of the synthesized nanomaterial was performed with various characterization techniques such as X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Atomic Force Microscopy (AFM) and Thermogravimetric analysis/Differential Scanning Calorimetry (TGA/DSC). The results interpreted from the various characterizations confirm the doping of RGO with sulphur as well as strong interaction of PANI nanofibers and S-RGO nanosheets. TG/DSC curves confirm the enhanced thermal stability of polyaniline/sulphur doped reduced graphene oxide (PANI/S-RGO) nanocomposites with heat resistance index (THRI) of 155.2 °C in comparision to pure PANI (THRI= 145.3 °C) at a filler loading of 10 wt. %. TGA validates that thermal stability of PANI/S-RGO nanocomposite improves by 6–7 °C than pure PANI in terms of weight loss percentage at a temperature of 1117 °C. However DSC analysis confirms that PANI/S-RGO retains its structural integrity and conformity to temperatures as high as 900 °C beyond which the polymer composite starts to degrade. The electromagnetic interference shielding effectiveness (EMI SE) of PANI and PANI/S-RGO nanocomposites were measured via open-ended coaxial probe set-up connected to a Vector Network Analyser (VNA) at a broadband frequency range of 1–20 GHz (1000–20000 MHz). For EMI SE measurements the various nanomaterials were incorporated into paraffin wax and made into composite pellets of thickness 5 mm by solution casting technique. The dielectric properties, electrical conductivity and EMI SE were all greatly enhanced for the PANI/S-RGO/Paraffin composite pellets. The as synthesized PANI/S-RGO/Paraffin composite pellets exhibited highest EMI SE of −22.5 dB (>99%) as compared to −15.89 dB of PANI/Paraffin composite pellets. The prepared composite pellets revealed an absorption dominant mechanism of shielding with highest SEA of −14.6 dB for PANI/S-RGO/Paraffin composite pellets.

Nickel decorated melamine-formaldehyde resin/polyaniline composites for high specific capacitance

Nickel decorated electro-conducting melamine-formaldehyde resin (MFR) composites were prepared in two steps. In the first step micron-sized electro-conducting MFR/polyaniline (PAni) composite particles were prepared by in situ seeded chemical oxidative polymerization of aniline in presence of mesoporous MFR seed particles. Then surface of MFR/PAni composite particles were decorated/doped with Ni particles via in situ chemical reduction of Ni(II) salt. The size, chemical composition and magnetic properties of the prepared composite particles named as MFR/PAni/Ni were analyzed by scanning election microscope (SEM), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET) surface analysis, Fourier Transform IR (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analyzer (TGA) and vibrating sample magnetometer (VSM). The results suggested that surface of MFR/PAni composite particles are best doped/decorated with Ni particles when MFR/PAni to Ni weight ratio was 1/0.1. An increase in Ni amount resulted in higher agglomeration and produced some free Ni particles. MFR/PAni/Ni composite particles possessed paramagnetic characteristics. The electrochemical/capacitive performance of MFR/PAni/Ni composite materials was evaluated by cyclic voltammetry (CV). Surface decoration/doping of MFR/PAni composite particles with increasing amount of Ni particles improved the specific capacitance value, suitable for application in supercapacitor.

Polyaniline as a Precursor of Multi-Layer Graphene: Microscopic and Microspectroscopic Study

Aluminosilicate-based nanocomposites containing multi-layer graphene were prepared from polyaniline/montmorillonite intercalate in two different forms: tablets and thin layers. Starting materials, polyaniline/montmorillonite powder and polyaniline/montmorillonite layers deposited on quartz glass, were prepared by in situ polymerization of aniline in presence of montmorillonite particles. Powder was compacted into tablets using pressure 400 MPa. Samples were calcined at 1300 °C in argon atmosphere and multi-layer graphene was formed from polyaniline in both cases as confirmed by Raman microspectroscopy. Changes in morphology and surface conductivity of uncalcined and calcined samples were observed using atomic force microscopy and conductive atomic force microscopy. Also the differences between surface and internal volume of tablets were studied. Conductive atomic force microscopy revealed that the most conductive areas can be found solely on the edges of aluminosilicate particles formed from montmorillonite during calcination process. Detailed observation of multi-layer graphene in these areas was performed using transmission electron microscopy.

Reduced Graphene Oxide / Polyaniline (rGO/PANI) Composite As Pt Support for Oxygen Reduction Reaction: Effect of PANI Content

In order to enhance the activity for oxygen reduction reaction by improving dispersion and distribution of platinum nanoparticles (Pt NPs), three composite materials were prepared and evaluated as cathode catalysts for fuel cells applications. Composite materials consisted on polyaniline grafted with reduce graphene oxide in three different compositions (rGO90-PANI10, rGO50-PANI50 and rGO10-PANI90). Graphene oxide (GO) was obtained by modified Hummer’s method using graphite as precursor and subsequently hybrid materials through in situ oxidative polymerization of aniline in presence of GO. Finally, deposition of Pt NPs was carried out by the polyol method. For comparative purpose a Pt/rGO material was prepared and evaluated under the same conditions. Materials were physicochemically characterized by X-Ray diffraction (XRD), infrared spectroscopy (FT-IR), transmission electronic microscopy (TEM) and thermogravimetric analysis (TGA) and evaluated by cyclic voltammetry for oxygen reduction reaction (RRO) in acid media. Characterization results demonstrated the formation of composite materials by the grafting of PANI. It was also observed that the amount of PANI leads to a higher dispersion and a low particle size, being of 1.5 nm for Pt/rGO10-PANI90 and 2.6 nm for Pt/rGO90-PANI10 which were lower compared to Pt/rGO (3.5 nm). The effect of PANI amount on the activity during evaluation of ORR was as follow: for lower amount of PANI a higher current density (j) and onset potential (E0) was observed, being the higher activity for Pt/rGO90-PANI10 with E0 = 0.85 V and j= 3.9 mA cm-1, which is even higher than Pt/rGO (0.77 V and 2.9 mA cm-1). The higher activity of Pt/rGO90-PANI10 is due to an optimum particle size, distribution and dispersion achieved with the composite support (rGO90-PANI10).

Semi self-doped electroconductive and biocompatible polyaniline/sulfonated β-cyclodextrin (PANI/SCD) inclusion complex with potential use in regenerative medicine

The aim of this study was to synthesize and characterize a semi self-doped polyaniline/sulfonated β-cyclodextrin (PANI/SCD) inclusion complex with an optimum electroconductivity and a maximized biocompatibility. In this work, β-cyclodextrin (CD) was sulfonated in which sulfonic acid group on the prepared SCD act as the dopant group. PANI/SCD inclusion complex was synthesized using interfacial oxidative polymerization of aniline in presence of SCD and was characterized by elemental analysis, 1H-NMR, FT-IR, XRD, SEM and EIS analyses. The electrical conductivity of the PANI/SCD inclusion complex was found about 2.23 µS⋅cm−1 in dedoped form and was almost equal to each of HCl doped PANI. Cytotoxicity of the PANI, PANI/CD, and PANI/SCD were studied both in HCl doped and dedoped forms using bone marrow-derived rabbit mesenchymal stem cells (rbMSCs) in compliance with ISO standard. Simultaneous effect of different parameters on cell biocompatibility of the synthesized materials investigated using two-way ANOVA and Tukey’s multiple comparison tests. Despite the fact that the PANI/SCD was found to be more cytotoxic than the PANI/CD, but due to its higher electrical conductivity, it can be considered as a material with optimum electroconductivity-biocompatibility balance and a potential use in tissue engineering and/or regenerative medicine as an electroactive scaffold.

Influence of monomer content on course of aniline polymerization in presence of high surface area carbon

A series of carbon/polyaniline (C/Pani) composites were synthesized by oxidative polymerization of aniline in the presence of carbon in acid media. Biomass-derived activated carbon (AC) having 1740m2/g surface area was used as the carbon component. The aniline loadings varied from 8 to 60wt%. A composition of the composites was determined by CHNS analysis. Porous structure of polyaniline, carbon and C/Pani composites was characterized with nitrogen adsorption at 77K. Structure of the composites, polyaniline and carbon was studied by Fourier transform infrared spectroscopy (FTIR). Electrochemical properties of the samples were investigated by cyclic voltammetry technique in 1M H2SO4 at 25°C. It has been shown that the aniline loading and presence of the carbon in the reaction mixture determine final product of the polymerization. At the aniline loading <30wt%, 4-aminodiphenilamine (4-ADPA) and phenazine-ring containing structures (PhzR) being intermediates in the aniline polymerization are predominantly formed and registered by electrochemical methods. Polyaniline formation is observed for the samples with aniline loading >40wt%.

Preparation and characterization of nanofibers of polyvinyl alcohol/polyaniline-montmorillonite clay

This work describes the preparation of polyvinyl alcohol/polyaniline-montmorillonite clay (PVA/PANI-OMMT) nanofibers through electrospinning. Initially, for improving the compatibility of the clay towards the organic polymer, the montmorillonite (MMT) was submitted to an organophilization process using hexadecyltrimethylammonium bromide (CH3(CH2)15N(Br)(CH3)3). The PANI-OMMT composite, which was obtained after the in situ polymerization of aniline in presence of the organophilic clay (ratio of ≈1:3 in weight), was then placed in a matrix of PVA (weight ratio of 1:7 of composite:PVA) for the production of the PVA/PANI-OMMT composite fibers through electrospinning. We used several characterization techniques (X-ray diffraction (XRD); infrared absorption spectroscopy (FTIR), ultraviolet visible absorption spectroscopy (UV–Vis), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS)) to analyze the different samples produced. The clay organophilization was confirmed after observing the (001) plane displacement from 5,6° to 4,7° and absorption bands in 2924 cm−1, 2853 cm−1 and 1479 cm−1, as analyzed by XRD and FTIR, respectively. The presence of polyaniline in its emeraldine salt was identified by the presence of the characteristic UV–Vis absorption bands in 360 nm, 430 nm and 822 nm, while the formation of the PANI/OMMT nanocomposite was confirmed by observing the characteristic FTIR bands of each individual component. From the SEM images, we could establish that the resulting nanocomposite mats were composed by uniform fibers with an average diameter of 240 nm and presented good surface quality. We have found that EIS is an efficient technique for the evaluation of changes in the electric properties of the nanofibers after their exposure to vapors of methanol. We suggest that this organic-inorganic composite may find useful applications in the preparation of several devices based on polymers, such as heavy metal filtration membranes and gas sensors.

Synthesis and enhanced electrochemical performance of PANI/Fe3O4 nanocomposite as supercapacitor electrode

Conducting polymer nanocomposites associated with metal oxides are emerging class of pseudocapacitive materials that exhibit enhanced electrochemical performance in energy storage applications. In this work, we fabricated polyaniline (PANI)/Fe3O4 nanocomposite (PFNC) through the in situ polymerization of aniline in presence of microwave synthesised Fe3O4 nanoparticles. The prepared PFNC was characterised by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The surface morphology was investigated by scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analysis. TEM studies revealed the presence of Fe3O4 nanoparticles wrapped by PANI with size in the range of 40–60 nm. The porous structure is validated by the associated morphology, where the voids are created by the formation of microspheres out of the nanospheres. These spaces boost the electrochemical activity of the PFNC by facilitating more sites for the insertion of electrolytic ions during the electrochemical reaction process. The fabricated PFNC on carbon felt offers the enhanced electrochemical properties and exhibits high specific capacitance (572 F g−1 at 0.5 A g−1), pronounced cycling stability (>5000 cycles at 1 A g−1) with good capacitance retention (82%). An excellent rate performance of 71.9% is also exhibited by the PFNC electrode with ten times the original current density (from 0.5 A g−1 to 5 A g−1). These out-standing characteristics prove that PFNC has a great potential to be exploited as highly efficient electrode materials for supercapacitors.

Polyaniline-β-Cyclodextrin-Graphene Nanocomposite for Energy Storage Application: Efficiency Enhancement through Radical Cation Stabilization

In this study, we report a novel supramolecular polyaniline-β-cyclodextrin-graphene nanosheet (PANI-β-CD-GNS) composite through in situ polymerization of aniline in presence of β-CD-GNS. The microstructure and morphology of the PANI-β-CD-GNS are characterized by various techniques. The enhanced radical cation stability of the composite is confirmed by electron paramagnetic resonance (EPR) spectroscopy. PANI-β-CD-GNS exhibits superior electrochemical properties than PANI-GNS such as a specific capacitance of 1071 F g−1 at 2 mV s−1, good long term cycling stability with 91.8% capacitance retention after 5000 cycles at 5 A g−1 current density. It is observed that high radical cation stability of PANI-β-CD-GNS showed significant impact on its electrochemical properties. The results of electrochemical analysis clearly indicate the potential usability of this material as novel organic radical supercapacitors for high-performance energy storage devices.

Evaluating the performance of citric acid as stabilizer and doping agent in an environment friendly approach to prepare electromagnetic nanocomposite particles

The objective of this investigation is to find a less‐expensive and less‐toxic environmentally benign route for the preparation of magnetic PANI nanocomposite particles. For this citric acid, a weak organic tricarboxylic acid has been used during seeded chemical oxidative polymerization of aniline in presence of variable amounts of Fe3O4 nanoparticles. Nanosized Fe3O4 particles are first prepared by co‐precipitation of Fe2+ and Fe3+ from their alkaline solutions. Then in the second step, magnetic nanocomposite particles—named as Fe3O4/PANI—are prepared by seeded chemical oxidative polymerization of aniline using ammonium persulfate (APS) as oxidant. Independent of Fe3O4 content, Fe3O4/PANI nanocomposite particles possessed comparable high electrical conductivity having the same magnitude as HCl‐doped PANI particles (2.13 × 10−3 S/cm). This result suggested that addition of citric acid during seeded chemical oxidative polymerization not only promoted solubilization of aniline but also functioned as stabilizer and doping agent. Iron oxide content critically influenced the stability, morphology, and magnetic properties of the produced nanocomposite particles. The saturation magnetization and magnetic susceptibility increased with the increase of Fe3O4 content. The nanocomposite particles prepared with core/shell ratio of 0.6/1 (w/w) exhibited the strongest paramagnetism and aligned into fiber‐like structure. The analysis of electromagnetic properties and spectral data from FTIR, X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and thermogravimetry (TG) confirmed the complete coverage of Fe3O4 nanoparticles by PANI layer. POLYM. COMPOS., 39:4628–4636, 2018. © 2017 Society of Plastics Engineers

Template polymerization of aniline in presence of poly(acrylamide-co-maleic acid) for preparation of conductive polymers

In the present work new conductive nanostructures based on poly (acrylamide-co-maleic acid) (PAAMA) and polyaniline were prepared. The template polymerization of aniline was conducted in the aqueous solution of PAAMA with different ratios (w/w%) of aniline to polyacid. The prepared composite was characterized by FTIR and UV–Vis spectroscopy, SEM, electrical conductivity measurements and solubility tests.

Improved electrochemical performances of polyaniline by graphitized mesoporus carbon: Hybrid electrode for supercapacitor

ABSTRACTIn this work, graphitized mesoporus carbon (GMC) was used to increase the specific capacitance and cycle stability of polyaniline (PANI). Hybrid material of polyaniline‐graphitized mesoporus carbon (GMCP) was prepared by in situ chemical polymerization of aniline in presence of sulphuric acid using ammonium persulfate oxidant with various amounts of GMC. Formation of hybrid sample was confirmed from X‐ray diffraction, and the composite sample was stable up to 250°C. Morphology, crystalline nature, and electrochemical performance of GMCP were compared with that of its individual components, GMC and PANI. GMC showed particle morphology and PANI showed nanofiber morphology. GMCP2 composite showed nanofibrous form of PANI grown on GMC (spherical form) along with PANI nanofibers. Higher crystallinity was obtained for GMCP than that of PANI. Cycling stability of GMCP2 was carried up to 12,000 cycles at 1200 W kg−1 and the retention capacitance was 66% of its original capacitance of 243 F g−1. With the same power density, GMC showed less capacitance value of 53 F g−1 with 92% retention and PANI showed capacitance of 187 F g−1 and it underwent 1500 cycles only. Higher supercapacitor performance was obtained for GMCP composite compared to that of its components, PANI and GMC. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42540.

Investigation of the Electro-Mechanical Behavior of Hybrid Polyaniline/Graphene Nanocomposites Fabricated by Dynamic Interfacial Inverse Emulsion Polymerization

This paper describes a study on electrical resistivity under loading of polyaniline (PANI)/graphene nanocomposite powders and compacts. The composites were prepared by an in-situ interfacial dynamic inverse emulsion polymerization technique under sonication of aniline in the presence of graphene sheets in chloroform. During polymerization the graphene nanoplatelets are coated with PANI and are well dispersed both in the polymeric suspension and then in the dried polymer matrix as evidenced by cryogenic transmission electron microscopy (Cryo-TEM) and high resolution scanning microscopy (HRSEM). The presence of graphene nanoplatelets lowers the electrical resistivity of the polyaniline by two orders of magnitude for both the powder and the compact composites as demonstrated by their electrical resistance measurements conducted under loading. The lowest measured electrical resistivity values were 5 Ω·cm for 33% wt. graphene powder and 8 Ω·cm for 41% wt. graphene compacted composites. Cyclic electrical measurements under loading showed a distinct reproducible dependence of the bulk resistivity vs. applied pressure. This repetition is a key component for electro-mechanical sensors. To the authors’ best knowledge, this is the first report on polymerization of aniline in presence of graphene by the in-situ interfacial dynamic inverse emulsion polymerization technique and also the first report on cyclic electrical measurements under pressure of PANI/graphene nanocomposites.

Composition‐dependent electrical and dielectric properties of polyaniline/graphene composites produced by in situ polymerization technique

Polyaniline (Pani)/Graphene nanocomposites with different compositions were prepared by in situ polymerization of aniline in presence of graphene oxide. Two types of Pani/graphene composites were prepared, composite‐1: where graphite powder as procured is used for preparation of composites, composite‐2: graphite powder is subjected ball milling for further reduction of graphite particles size and then used for preparation of composites. DC and AC resistivity of these composites have been found to be composition dependent. In fact composite‐2 exhibit lower resistivity compared to composite‐1 at same composition. However, both composites show frequency‐independent AC resistivity but frequency‐dependent dielectric constant and loss. POLYM. COMPOS. 36:445–453, 2015. © 2014 Society of Plastics Engineers

Biodegradable polyaniline/dextrin conductive nanocomposites: synthesis, characterization, and study of antioxidant activity and sorption of heavy metal ions

Conductive nanocomposites based on polyaniline/dextrin were synthesized by in situ polymerization of aniline in presence of dextrin. The nanocomposites were characterized by field emission scanning electron microcopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, X-ray diffraction and conductivity measurements. It was observed that the conductivity values increased with the increase of aniline content in nanocomposites. The obtained nanocomposites have been analyzed for the antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl assay. The results showed that the antioxidant activity of the nanocomposites was enhanced by increasing the aniline content. Polyaniline/dextrin nanocomposites were used as sorbent materials for the removal of heavy metals from aqueous solutions. The sorption data indicated that the novel polyaniline/dextrin nanocomposites have high tendency for the removal of heavy metal ions such as Cu(II), Cd(II) and Pb(II) from aqueous solutions. In addition, the in vitro biodegradability of polyaniline/dextrin nanocomposites with different weight ratios was studied by soil burial tests. The result demonstrated that the nanocomposites are biodegradable under soil environment by degradation range between 30.18 and 74.52 %. The observed physical properties of the polyaniline/dextrin nanocomposites open interesting possibilities for novel applications of electrically conducting polysaccharide-based composites, particularly those that may exploit the antioxidant activity and heavy metal ions sorption of the polyaniline/dextrin nanocomposites.

A promising approach to enhanced thermal stability of DC conductivity of polyaniline - functionalised multi-walled carbon nanotube composites

Nanocomposites of polyaniline and 4-aminobenzoyl functionalised multiwalled carbon nanotubes (PANI-FMWCNT) were synthesised through interfacial polymerisation of aniline in presence of FMWCNT and protonating with various dopants. The composites were characterised by SEM, TEM and TGA. The high temperature DC conductivity stability was investigated through cyclic accelerated ageing and isothermal ageing studies. On thermal cyclic treatment up to 150°C, after the fifth cycle, electrical conductivity for various acid doped PANI samples rapidly dropped to 42–59% of their initial values, while PANI-FMWCNT samples showed only negligible decrease to 80–87%. Isothermal ageing studies showed that the PANI samples started reduction in conductivity at 110°C whereas nanocomposites retained conductivity stability even at 140°C. Both neat PANI and composites containing NSA and TSA had a higher thermal stability of electrical properties than polyaniline doped with HCl and H2SO4. The role of FMWCNTs in stabilising the DC conductivity of composites at elevated temperature is discussed.

H2S sensing using in situ photo-polymerized polyaniline–silver nanocomposite films on flexible substrates

We demonstrate the preparation of flexible polyaniline–silver (PANI–Ag) nanocomposite films via an in situ facile UV induced polymerization of aniline in presence of AgNO3. The flexible substrates used were (3-aminopropyl)trimethoxysilane (APTMS) modified biaxially oriented polyethylene terephthalate (BOPET) substrates. The APTMS modification of BOPET surface has two advantages: (i) improved adhesion of the films, and (ii) directional growth of polymer perpendicular to the substrate plane, leading to nanobrush-like morphology. The PANI–Ag films have been characterized by various techniques, such as, UV/Vis, FTIR, Raman, SEM and XPS. These films were found to be highly selective and sensitive to the H2S i.e. chemiresistive response of ∼100% at 10ppm with a reasonably fast response time of 6min. PANI–Ag films prepared on pristine BOPET exhibits chemiresistive response of ∼67% at 10ppm of H2S exposure. In contrast pure PANI films did not exhibit any response on exposure to H2S. The plausible mechanism(s) of H2S sensing have been discussed. This study highlights the importance of surface modification and the role of Ag in PANI matrix for H2S sensing.