Doping of the Processable Conducting Poly(m-Aminophenol) with Inorganic Acids

Poly(m-aminophenol) (PmAP) was synthesized from m-aminophenol (mAP) in aqueous sodium hydroxide (NaOH) using ammonium persulfate (APS) as an oxidative initiator. Free standing PmAP films were cast from dimethyl sulfoxide (DMSO) solution of the polymer. Then the film was doped with various inorganic acids using a solution doping technique. Various inorganic acid doped PmAP films were characterized by ultraviolet-visible (UV-Vis), Fourier transform infrared (FTIR), and energy dispersive X-ray (EDS) spectroscopies, X-ray diffraction (XRD) analysis and elemental (C, H, N, S, O) analysis. All the results were explained on a comparative basis and the doping scheme was proposed. The DC-conductivity of the inorganic acid doped films was measured using a standard four-probe method. From the DC-conductivity measurements it was found that sulfuric acid had a better doping effect in terms of conductivity than that of the other inorganic acids used, perchloric acid and phosphoric acid. An explanation of the reason for the better doping effect of sulfuric acid than that of the other inorganic acids is given.     

Effect of the Protonation and Chemical Doping of Poly(o-toludine) with Copper Sulfate on the Spectral and Electrical Properties of the Host Polymer

Poly(o-toluidine) (POT) and its samples doped with copper sulfate, a transition metal salt, were synthesized by a chemical oxidative polymerization technique using potassium dichromate as oxidant in aqueous hydrochloric acid medium and chemical doping with copper sulfate. The prepared polymeric samples were characterized by ultraviolet (UV)-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction, and DC conductivity measurement techniques. The UV-visible spectra of doped polymer displayed peaks indicating the presence of charged particles/polarons and/or formation of conducting POT. The characteristic FTIR peaks of the doped polymer provided information regarding structural changes in the backbone of POT and were consistent with the interaction of the benzenoid groups of the polymer with metal ions. X-ray diffraction patterns of powdered doped polymer showed an amorphous nature, as exhibited by most conducting polymers. The DC conductivity of doped polymer was measured by a two-probe method in the temperature range of 300–400 K; a significant enhancement in DC conductivity was observed with an increase in temperature, showing the semiconductor nature of the synthesized doped polymer.     

Synthesis and study of conductivity behaviour of blended conducting polymer films irradiated with swift heavy ions of silicon

In recent times, blended polymers have shown a lot of promise in terms of easy processability in different shapes and forms. In the present work, polyaniline emeraldine base (PANi-EB) was doped with camphor sulfonic acid (CSA) and combined with the conducting polymer polyfluorene (PF) as well as the insulating polymer polyvinyl chloride (PVC) to synthesize CSA doped PANi–PF and PANi–PVC blended polymers. It is well known that PANi when doped with CSA becomes highly conducting. However, its poor mechanical properties, such as low tensile, compressive, and flexural strength render PANi a non-ideal material to be processed for its various practical applications, such as electromagnetic shielding, anti-corrosion shielding, photolithography and microelectronic devices etc. Thus the search for polymers which are easily processable and are capable of showing high conductivity still continues.PANi–PVC blend was prepared, which showed low conductivity which is limiting factor for certain applications. Therefore, another processable polymer PF was chosen as conducting matrix. Conducting PF can be easily processed into various shapes and forms. Therefore, a blend mixture was prepared by using PANi and PF through the use of CSA as a counter ion which forms a “bridge” between the two polymeric components of the inter-polymer complex.Two blended polymers have been synthesized and investigated for their conductivity behaviour. It was observed that the blended film of CSA doped PANi–PVC showed a room temperature electrical conductivity of 2.8×10⁻⁷ S/cm where as the blended film made by CSA doped PANi with conducting polymer PF showed a room temperature conductivity of 1.3×10⁻⁵ S/cm.Blended films were irradiated with 100 MeV silicon ions with a view to increase their conductivity with a fluence ranging from 10¹¹ ions to 10¹³ per cm² from 15 UD Pelletron accelerator at NSC, New Delhi.     

A new hyperbranched star polyether electrolyte with high ionic conductivity

Hyperbranched poly(glycidol) containing hydroxyl groups was firstly synthesized via anionic polymerization and then reacted with 2-bromoisobutyl bromide to form macroinitiator HPG-Br. Finally, a hyperbranched star polymer (HPG-PPEGMA) was successfully prepared by atom transfer radical polymerization (ATRP) of poly(ethylene glycol) methyl ether methacrylate using HPG-Br as macroinitiator. The structures and properties of the obtained polymers were characterized by ¹H NMR, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The ionic conductivity of the polymer electrolytes composed of HPG-PPEGMA and lithium bis(trifluoromethanesulfonimide) (LiTFSI) was investigated via electrochemical impedance spectroscopy. The results showed that the room temperature ionic conductivity of the prepared hyperbranched star polymer electrolytes had a higher ionic conductivity. When [EO]/[Li] was 20, the ionic conductivity of the hyperbranched star polymer electrolyte was up to 1?×?10^?4 Scm^?1 at 30 °C. The onset decomposition temperature of the hyperbranched star polyether could reach 374 °C, indicating that the hyperbranched star polymer had a good thermal stability. The XRD results showed that the structure of the hyperbranched star polymer was beneficial to improve the ionic conductivity due to possessing a low degree of crystallinity.     

Chemical Composition of Porous Silicon Formed in Aqueous and Aqueous-Alcoholic Electrolytes, According to the IR Spectroscopy Data

The chemical composition of the surface of porous silicon synthesized on weakly doped silicon of the n type of conductivity (KÉF-20) with the crystallographic orientation (100) (100) in aqueous and aqueous-alcoholic electrolytes with different HF concentrations has been analyzed by IR spectroscopy.     

A Novel Porphyrin-Labeled Poly(N-Isopropylacrylamide): Spectral and Luminescent Properties

A novel water-soluble tetraarylporphyrin-containing polymer has been synthesized by the reaction of bromoalkyl-containing poly(N-isopropylacrylamide) with 5-(4-pyridyl)-10,15,20-tri(4-methoxyphenyl)porphyrin. Some physicochemical properties of the obtained polymers are reported. It has been shown that a strong interaction between the porphyrin units takes place in liquid aqueous medium at temperatures below the lower critical solution temperature (LCST). This phenomenon results in considerable broadening of the Soret band in the absorption spectrum and in strong quenching of fluorescence. Higher than LCST fluorescence enhancement is observed.     

Influence of structure of poly(<Emphasis Type="Italic">o</Emphasis>-phenylenediamine) on the doping ability and conducting property

Poly(o-phenylenediamine) with ladder-type structure was formed in aqueous hydrochloric acid medium below pH 1, while open ring-type amine derivative, i.e., ?NH₂ functional group substitution of polyaniline structure, was obtained in 1:1 aqueous sulfuric acid medium from the chemical synthesis of the monomer o-phenylenediamine. However, poly(o-phenylenediamine) having structure like polyaniline derivative with free =NH functional groups was obtained by chemical synthesis in dimethyl sulfoxide medium. The ladder-type polymer was almost insoluble but the other two types of synthesized polymers having polar functional group substitutions were well soluble in polar organic solvent like dimethyl sulfoxide, N,N-dimethyl formamide, and tetrahydrofuran. The freestanding films were cast from dimethyl sulfoxide solution of both the soluble functional polymers. The polymers having different structures were doped with inorganic acid by solution doping technique and the doped polymers were characterized by various standard characterizations. In order to explore the electronic uses of the polymers like sensor and actuators, the influences of their structure on the doping ability as well as ionic properties of the sulfuric acid-doped polymers were compared.     

Interaction of oxygen (O+7) ion beam on polyaniline thin films

High-energy ion beam irradiation of the polymers is a good technique to modify the properties such as electrical conductivity, structural behaviour and mechanial properties. Polyaniline thin films doped with hydrochloric acid (HCl) were prepared by oxidation of ammonium persulphate. The effect of Swift Heavy Ions irradiation on the electrical and structural properties of polyaniline has been measured in this study. Polyaniline films were irradiated by oxygen ions (energy 80 MeV, charge state O⁺⁷) with fluence varying from 1 × 10¹⁰ to 3 × 10¹² ions/cm². The studies on electrical and structural properties of the irradiated polymers were investigated by measuring V-I using four probe set-up and X-ray diffraction (XRD) using Bruker AXS, X-ray powder diffractometer. V-I measurements shows an increase in the conductivity of the film, XRD pattern of the polymer shows that the crystallinity improved after the irradiation with Swift Heavy Ions (SHI), which could be attributed to cross linking mechanism.      

Electrical Conductivity in Polyazomethines: A Novel Mechanism Derived from All Valence MO Calculation and IR Study of Polymer–Dopant Interaction

A simple mechanism is proposed to explain the variation of electrical conductivity in polyazomethines. The results of semiempirical, all valence, molecular orbital calculations obtained from the PM3 method have been employed to arrive at the mechanism. The difference of energy (ΔE) between highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) alone could not explain the variation in electrical conductivity; however, ΔE together with the LUMO electron density at the atoms that lie on the continuous chain could account for the electrical conductivity in these polymers. The LUMO electron density on these centers may be visualized as the carrier movement. In certain polymers there are intrinsic holes in HOMO. The movement of these intrinsic holes also adds to the electrical conduction. The polyazomethines are prepared by the condensation of diamines with azo bis-aldehydes. A few of these polymers were doped with silver nanoparticles. Many of the doped polymers showed substantial enhancement in conductivity. Strong polymer–dopant interaction, identified by IR spectroscopy, is proposed to be responsible for the increase in conductivity.     

Structural and electrical characterizations of 50:50 PVA:starch blend complexed with ammonium thiocyanate

The present work deals with the preparation and characterization of polymer blend electrolyte films. Glutaraldehyde is used as a cross-linker to cross-link polymers polyvinyl alcohol (PVA) and starch for the proper film formation. Structural characterizations such as X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) have been performed. X-ray diffraction is done to investigate the amorphous nature of the sample. FTIR study confirms about the complexation of salt with the polymer and interaction of thiocyanate ion with the polymer matrix. Electrical characterizations were done using impedance spectroscopy. DC and AC ionic conductivity was obtained at varying salt concentration in the films which shows maximum ionic conductivity of the polymer electrolyte containing 30 wt% of salt content. The AC conductivity behaviour of the polymer electrolyte follows Jonscher’s power law. Dielectric parameters such as dielectric constant, dielectric loss and loss tangent have been determined. Relaxation time is obtained and decreases to lower value with the increase in the salt concentration in the polymer electrolyte.     

Structural and thermal studies of PVA:NH4I

Proton-conducting polymer electrolytes based on poly vinyl alcohol (PVA; 88% hydrolyzed) and ammonium iodide (NH₄I) has been prepared by solution casting method with different molar ratios of polymer and salt using DMSO as solvent. DMSO has been chosen as a solvent due its high dielectric constant and also its plasticizing nature. The ionic conductivity has been found to increase with increasing salt concentration up to 25 mol% beyond which the conductivity decreases and the highest ambient temperature conductivity has been found to be 2.5×10⁻³ S cm⁻¹. The conductivity enhancement with addition of NH₄I has been well correlated with the increase in amorphous nature of the films confirmed from XRD and differential scanning calorimetry (DSC) analyses. The temperature-dependent conductivity follows the Arrhenius relation. The polymer-proton interactions have been analyzed by FTIR spectroscopy.     

Synthesis, characterization, and corrosion protection properties of poly(N-(methacryloyloxymethyl) benzotriazole-co-methyl methacrylate) on mild steel

The copolymers from different feed ratios of N-(methacryloyloxymethyl) benzotriazole (MMBT) and methyl methacrylate (MMA) has been synthesised using free radical solution polymerization technique and characterized using FT-IR and ¹³C NMR spectroscopy. The thermal stability of the polymers was studied using theremogravimetrtic analysis (TGA). The corrosion behaviors of mild steel specimens dip coated with different composition of copolymers have been evaluated by potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) method. These electrochemical properties were observed in 0.1 M HCl medium. The polarization and impedance measurements showed different corrosion protection efficiency with change in composition of the copolymers. It was found that the corrosion protection properties are owing to the barrier effect of the polymer layer covered on the mild steel surfaces. However, it was observed that the copolymer obtained from 1:1 mole ratio of MMBT and MMA exhibited better protection efficiency than other combinations.     

Enhanced dielectric properties and energy storage density of interface controlled ferroelectric BCZT-epoxy nanocomposites

Polymer nanocomposites with ferroelectric fillers are promising materials for modern power electronics that include energy storage devices. Ferroelectric filler, Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃ (BCZT) nanopowder, was synthesized by sol-gel method. X-ray diffraction (XRD) studies confirmed the phase purity and the particle size distribution was determined by transmission electron microscopy (TEM). Extended aromatic ligand in the form of naphthyl phosphate (NPh) was chosen for surface passivation of BCZT nanoparticles. Surface functionalization was validated by thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and impedance spectroscopy using slurry technique. The dielectric constant of surface-passivated BCZT nanopowder was ~155, whereas pristine BCZT nanopowder dielectric constant could not be assessed due to high innate surface conductivity. Furthermore, BCZT–epoxy nanocomposite films were prepared and analyzed by differential scanning calorimetry (DSC), dielectric spectroscopy, dielectric breakdown strength (DBS), and scanning electron microscopy (SEM). Owning to stronger polymer–particle interface, dielectric measurements of 5 vol.% NPh surface functionalized BCZT–epoxy nanocomposites indicated improved DBS and glass transition temperature (T_g), reduced dielectric loss, and enhanced energy storage density compared to untreated BCZT–epoxy composites and pure epoxy. The energy storage density of 30 vol.% NPh surface functionalized BCZT–epoxy nanocomposite of 20 μm film thickness was almost three times that of pure epoxy polymer of identical film thickness.     

Role of polyvinyl alcohol in the conductivity behaviour of polyethylene glycol-based composite gel electrolytes

An attempt has been made in the present work to combine gel and composite polymer electrolyte routes together to form a composite polymeric gel electrolyte that is expected to possess high ionic conductivity with good mechanical integrity. Polyethylene glycol (PEG) based composite gel electrolytes using polyvinyl alcohol (PVA) as guest polymer have been synthesized with 1 molar solution of ammonium thiocyanate (NH₄SCN) in dimethyl sulphoxide (DMSO) and electrically characterized. The ionic conductivity measurements indicate that PEG:PVA:NH₄SCN-based composite gel electrolytes are superior (σ _max = 5.7 × 10⁻² S cm⁻¹) to pristine electrolytes (PEG:NH₄SCN system) and conductivity variation with filler concentration remains within an order of magnitude. The observed conductivity maxima have been correlated to PEG:PVA:NH₄SCN-and PVA:NH₄SCN-type complexes. Temperature dependence of conductivity profiles exhibits Arrhenius behaviour in low temperature regime followed by VTF character at higher temperature.      

Structural, vibrational, thermal, and electrical properties of PVA/PVP biodegradable polymer blend electrolyte with CH3COONH4

A biodegradable solid polymer blend electrolyte was prepared by using polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) polymers with different molecular weight percentages (wt.%) of ammonium acetate, and its structural, thermal, vibrational, and electrical properties were evaluated. The polymer blend electrolyte is prepared using solution casting technique, with water as a solvent. X-ray diffraction shows that the incorporation of ammonium acetate into the polymeric matrix causes decrease in the crystallinity degree of the samples. The Fourier transform infrared spectroscopy and laser Raman studies confirm the complex formation between the polymer and salt. Differential scanning calorimerty shows that the thermal stability of the polymer blend electrolyte and the glass transition temperature decreased as the concentration of ammonium acetate increased. The ionic conductivity of the prepared polymer electrolyte was found by AC impedance spectroscopic analysis. A maximum conductivity of 8.12?×?10^?5 Scm^?1 was observed for the composition of 50 PVA/50 PVP/30 wt.% of CH₃COONH₄.     

Effect of ionic liquid incarceration during free radical polymerization of PMMA on its structural and electrical properties

The thin film of poly(methyl methacrylate) (PMMA) has been widely studied as host in a polymer electrolyte system due to its good mechanical stability towards lithium electrode. However, the brittle property of this film creates additional resistance for the ionic conduction. The addition of ionic liquid (IL) has been noticed to improve the brittleness of the film. In addition, its ionic conductivity can also be enhanced, but no free standing film can be obtained when higher amount of IL was added. Therefore, in this study, 1-methyl-3-pentamethyldisiloxymethylimidazolium bis(trifluoromethylsulfonyl)imide,[(SiOSi)C₁C₁im][NTf₂], was incarcerated during free radical polymerization of MMA. Interestingly, this newly synthesized PMMA (PMMA_IL) gives a flexible and transparent film with ionic conductivity of ～10^?7 S/cm at room temperature. The structural properties of this PMMA_IL were further investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and optical microscope (OM).     

Waterproof Light-Emitting Metal Halide Perovskite–Polymer Composite Microparticles Prepared via Microfluidic Device

Waterproof light-emitting perovskite–polymer composite microparticles are synthesized by a continuous one-step microfluidic reactor, which enables in situ production of metal halide perovskite nanoparticles (MHP-NPs) by the ligand-assisted reprecipitation process (LARP) and the encapsulation of MHP-NPs by UV cross-linking polymerization in the microfluidic channel. Successful encapsulation of MHP-NPs in polymer microparticles is attributed to the co-dispersion of an LARP solution and UV polymerizable solution in an aqueous continuous phase within the microfluidic channel, in which N,N-dimethylformamide, in co-dispersion droplets, is continuously extracted to the aqueous medium upon UV polymerization. MHP-NPs–polymer composite microparticles show enhanced stability against air and moisture.     

Electrical and structural properties enhancement in plasticized high Tg polymers using metal salts

Plasticized polymer electrolyte composite has been prepared in the form of a film by solution casting method. Poly (ethyl methacrylate) (PEMA) acts as a host polymer and is doped with Sodium Iodide (NaI). Ethylene carbonate (EC) added as a plasticizer and also enhances amorphicity of the polymer electrolyte. The electrical conductivity of the PEMA+NaI was evaluated using complex impedance spectroscopy. Maximum ionic conductivity obtained at room temperature was 8.75 × 10^?6 S/cm with the composition of PEMA: NaI (30%) + 60% EC. The conductivity further increased with increase in temperature and moved up to 5.8 × 10^?5 S/cm. Scanning electron microscopy was used to study the surface morphology of the composite film. Fourier transform infrared ray and X-ray diffraction data confirmed the complexation of material.     

Laser photoelectron projection microscopy of an organic conducting polymer

A conducting organic polymer is visualized on a laser photoelectron projection microscope, which is based on Letokhov’s concept and has a nanometer spatial resolution. Photoelectron images of polyaniline (which is the most promising representative of conducting polymers) with a magnification of ∼10⁵ have been obtained when a 100-nm quartz capillary coated with a film of this material was irradiated by femtosecond laser pulses. The projection photoelectron method using 400- and 800-nm laser radiation has made it possible to directly reveal the existence of the redox heterogeneity of the organic polymer, which is due to the contact of the sections of polyaniline with different oxidation degrees and strongly affects the electric conductivity of the sample.     

Development of poly(glycerol suberate) polyester (PGS)–PVA blend polymer electrolytes with NH<Subscript>4</Subscript>SCN and its application

Besides commercially available synthetic polymers, the present work has been undertaken to explore the significance of poly(glycerol suberate) (PGS) polyester synthesised under lab scale in energy storage device. In this regard, a blend polymer electrolyte comprising of polyvinyl alcohol (PVA), poly(glycerol suberate) (PGS) polyester along with the various proportions of ammonium thiocyanate (NH₄SCN) was prepared adopting solution casting technique. The synthesised polyester PGS was characterised by Fourier transform infrared (FT-IR) spectroscopy, ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy. The prepared electrolyte film was subjected to FT-IR analysis to study the complexation that has occurred within the blend. Its amorphous nature was revealed from X-ray diffraction (XRD) studies. Influence of NH₄SCN on the glass transition temperature (T_g) was drawn from differential scanning calorimetry (DSC) technique. The dispersion of dopant within the polymer matrix was supported by scanning electron microscopy (SEM) followed by its elemental composition from energy dispersive spectroscopy (EDS). From the AC impedance technique, maximum conductivity of 3.01?×?10^?4 S cm^?1 was elicited for the optimised electrolyte (1 g PVA?+?0.75 g PGS?+?0.6 g NH₄SCN). Frequency-dependent dielectric and modulus spectra were analysed to study the mechanism of transportation. Transport parameters evaluated by Wagner’s polarisation method proved that the conductivity was predominantly due to cations. Proton conducting battery was configured with the highest conducting electrolytic film and its cell parameters are presented.