Polypyrrole Content Research Articles

Study of Electrical and Mechanical Properties of Polypyrrole-Coated Three-Dimensional Spacer Fabric

In this study, the liquid phase oxidative polymerization method was utilized to prepare polypyrrole conductive three-dimensional spacer fabrics. By controlling pyrrole solution, oxidant FeCl3 solution, dopant p-toluene sulfonic acid concentration and reaction time, the optimal process for the preparation of conductive spacer fabrics was obtained. This led to the best preparation process of polypyrrole-coated three-dimensional spacer conductive fabric (polypyrrole/three-dimensional spacer fabrics) being obtained. The results showed that the conductive properties of polypyrrole/three-dimensional spacer fabrics were the best when 0.10 mol/L pyrrole, 0.40 mol/L oxidant FeCl3 solution, and 0.40 mol/L dopant p-toluene sulfonic acid were prepared within a 2-h reaction time. The properties of polypyrrole/three-dimensional spacer fabrics were analyzed using the results from surface resistance, Fourier transform-infrared spectroscopy, mechanical properties, and stability tests. The results showed that polypyrrole was well attached to the three-dimensional spacer fabric surface, and the concentration of polypyrrole in the fabric exhibited an inverse correlation with changes in surface resistance. The mechanical properties of polypyrrole/three-dimensional spacer fabrics after treatment exhibit superior performance, with consistent changes in the meridional and zonal electrical properties during tensile testing and can maintain excellent long-term electrical stability in atmospheric environments.

Synergistic effect of silica/polypyrrole nanocomposites synthesized by hydrothermal method using rice husk as a silica source for corrosion protection

Rice husk, a plentiful agricultural waste, is a natural and environmentally friendly silica reservoir. In this study, a hydrothermal synthesis was employed to produce silica/polypyrrole nanocomposites, with the primary objective of developing corrosion-resistant materials. The nanocomposites are comprehensively characterized using XRD, FTIR, FESEM, and electrochemical studies. The results confirmed the successful formation of a silica/polypyrrole nanocomposite and revealed that the adsorption of polypyrrole molecules onto silica clusters controls the formation of larger silica nanoparticles. Pure silica exhibits spherical particles ranging from 500 to 1 μm. A low concentration of polypyrrole results in nanoparticles with dimensions ranging from 100 to 200 nm, while a higher concentration leads to reduced silica nanoparticles with sizes 10–20 nm. Aggregation of spherical nanoparticles is more prominent in silica/polypyrrole nanocomposites than pure silica nanoparticles. The nanocomposites of silica/polypyrrole, namely SP-1, SP-2, and SP-3, demonstrated significantly higher corrosion resistance (Rct) values of 36613 Ω, 44536 Ω, and 49060 Ω, respectively, in comparison to the pure silica (19540 Ω). The corrosion rates of pure silica, SP-1, SP-2, and SP-3 were determined to be 1.2687 mm/yr, 0.4715 mm/yr, 0.4681 mm/yr, and 0.3042 mm/yr, respectively. Silica exhibits remarkable chemical stability and exceptional corrosion resistance, whereas polypyrrole is a conducting polymer endowed with distinctive electrical characteristics. These constituents can be synergistically combined within a nanocomposite matrix, enhancing corrosion resistance. The synthesized nanocomposite exhibits considerable promise as a corrosion-resistant coating agent, presenting a sustainable remedy for corrosion mitigation in different industrial contexts.

Design of BCNO@PPy composites for efficient microwave absorption and thermal management

Currently, multifunctional microwave-absorbing materials, especially those with thermal conductivity and microwave absorption functions, have excellent application prospects in electronic packaging. In this study, we first used a sacrificial template method to prepare BCNO using biomass carbon as a template. Then, we used an in-situ synthesis method to grow polypyrrole (PPy) on the surface of BCNO to prepare BCNO@PPy with a core-shell structure. The BCNO@PPy composite exhibits a minimum reflection loss (RLmin) of −52.6 dB at a thickness of only 1.94 mm and an effective absorption bandwidth (EAB) of 5.3 GHz (12.7–18 GHz). The excellent microwave absorption can be attributed to the synergistic effect of polarization loss, conductive loss, and partial magnetic loss in the BCNO@PPy (BPPy) composites, and the multi-wall reflection effect of the core-shell structure, as well as the excellent impedance matching of the composites. Notably, BPPy-3 (polypyrrole content of 28.5 wt%) showed a good thermal conductivity enhancement effect on the epoxy resin (EP) when the content of BPPy-3 was 30 wt%. BPPy-3/EP has a thermal conductivity of 1.82 W(m·K)−1, which is 619.5 % higher than that of pure EP. The good thermal conductivity of the composites is attributed to the excellent compatibility of PPy and epoxy resin, as well as the low interfacial thermal resistance between BCNO and PPy. Therefore, this work can provide a reference for the design of materials with both thermal conductivity and microwave absorption functions.

Evaluation of templated N/P co-doped hierarchical mesoporous biocarbon/2D-molybdenum disulfide/polypyrrole composite as a supercapacitor electrode for U(VI) electrosorption

In this work, a templated N/P co-doped hierarchical porous biocarbon was prepared through the carbonization of sugar at high temperature (700 °C). Then, this porous biocarbon was in-situ functionalized with molybdenum disulfide nanosheets through a hydrothermal treatment reaction to get the composite, SC/MoS2. Later, SC/MoS2 on a nickel foam substrate was electrodeposited with different concentrations of polypyrrole, a conducting polymer, at −0.9 V. The prepared composite electrodes (SC/MoS2/PPy) were characterized thoroughly using FTIR, XRD, BET, and SEM. The orderly developed mesoporosity and N, P doping inside the porous carbon network was found to be highly conducive for the U(VI) electrosorption accomplished through capacitive deionization (CDI). The composites had remarkable specific capacitance (95.4 F/g), a large specific surface area (174.4–273.6 m2/g), improved mesopore volume (0.58 cm3/g) and excellent Vm/Vt ratio (0.80). SC/MoS2/PPy-2, among other composites, revealed fast electrosorption kinetics and excellent selectivity with a maximum sorption capacity of 300.66 ± 8.02 mg/g at −0.9 V. The SC/MoS2/PPy-2 retained relatively small charge transfer resistance Rct (1.22 Ω cm2), minute electrolytic resistance Rs (0.77 cm2), and a large double layer constant phase element qdl (0.0369 S sn/cm2) which makes it suitable for U(VI) ion diffusion and fast electron transfer during CDI performance. The composite electrode materials offer novel and potent desalination applications, specifically in uranium extraction from aqueous media.

(Digital Presentation) The Optimization of Polypyrrole Concentration to Synthesize Hollow Fe, Co, and Nitrogen Doped Carbon Spheres with Improved Oxygen Reduction Reaction Performance

Transition metal and nitrogen co-doped carbon materials (M-N-C, M=Fe, Co, Ni, etc.) have recently emerged as front runners to replace commercial Pt/C for the oxygen reduction reaction (ORR) due to their natural availability and excellent electrocatalytic activity. The development of M-N-C materials with optimized active sites using a secondary nitrogen source has attracted a lot of attention as ORR catalysts for their high activity and excellent durability. Polypyrrole (PPy) has become an attractive secondary nitrogen source for increased nitrogen doping and metal dispersion. Herein, we developed hollow Fe, Co, and nitrogen-doped carbon (H-FeCo-NC) spheres using the composites of metal-organic frameworks (MOFs) materials and PPy. Based on X-ray absorption fine spectroscopy analysis, X-ray photoelectron spectroscopy, and transmission electron microscopy, the active centers and the role of PPy for ORR catalytic performance are explored. The H-FeCo-NC not only displayed remarkable ORR performance in alkaline media, with a half-wave potential of 0.903 V, but also showed excellent stability and durability. The results outperformed the commercial Pt/C catalyst, demonstrating the potential of utilizing PPy for improved ORR performance.

Polypyrrole-Coated Melamine Sponge as a Precursor for Conducting Macroporous Nitrogen-Containing Carbons

Macroporous open-cell melamine sponges were coated with a conducting polymer, polypyrrole, during in-situ oxidative polymerization of pyrrole. Two samples, differing in polypyrrole content, 8.2 and 27.4 wt%, were prepared. They were exposed to various temperatures up to 700 °C in an inert atmosphere. The macroporous structure and mechanical integrity were preserved after this process. This converted both the polypyrrole coating and the melamine sponge to macroporous nitrogen-containing carbons. The changes in molecular structure in the course of carbonization were followed by elemental analysis and FTIR and Raman spectra. The specific surface area of polypyrrole-coated sponge increased from ca. 90 to ca. 300 m2 g−1 along with accompanying increase in the porosity. The conductivity of the sponges was recorded as a function of compression in a newly developed apparatus. The sponge containing 27.4 wt% pyrrole had conductivity of the order of 10−2 S·cm−1 at 0.1 MPa pressure, which was reduced by four orders of magnitude when exposed to 400–500 °C and nearly recovered after the temperature reached 700 °C. The sponges were tested in electromagnetic radiation shielding and displayed both radiation absorption and, to a lower extent, radiation reflection proportional mainly to the samples’ conductivity.

In vitro biocompatibility study of microwave absorbing conducting polymer blend films for biomedical applications

Abstract In the present communication, microwave absorbing property in the frequency range of 12.4–18 GHz and in vitro biocompatibility studies of light weight, flexible, biocompatible, and environment friendly polymer blend films of polyvinylchloride (PVC)-polyvinylpyrrolidone (PVP) (taken in ratio 1:1) and doped with various percentage weight concentration of polypyrrole (PPy) are reported. Addition of PPy in the PVC-PVP matrix exhibited a synergetic effect in improving microwave absorbing property. PVC-PVP blend film with 40 and 50% concentrations of PPy were seen to absorb microwaves of the order of 28–50 dB in ku band of microwave region indicating that this composition can suitably find application as microwave absorbing material. In vitro biocompatibility skin irritation study of PVC-PVP (taken in ratio 1:1) with 50% weight concentration of PPy indicated that the prepared film did not have any irritation upon administration and hence is safe for topical application. Moreover, the blood compatibility study of this film exhibited compatibility with blood and can safely be used in any blood contacting mask/device. Hence, this biocompatible film can potentially be used as microwave absorbing material for masking some parts of human body or can be interfaced to biological systems or devices.

Synthesis and Optical Properties of Chitosan/polypyrrole Composite for Biological Applications

Polypyrrole conducting polymers have become significant in different biomedical applications, but unfortunately, they are insoluble with poor mechanical properties. A natural soluble polymer (Chitosan) can be used to improve such properties. Chitosan/polypyrrole composites were synthesized by dispersing the different doped amounts of polypyrrole into the chitosan matrix. The physical properties of the synthesized composite films were investigated using different techniques. The results obtained from FTIR, XRD show the electrostatic interaction between chitosan and polypyrrole. UV/Vis analysis implies that the optical band gap of composite films decreases with increasing polypyrrole concentration, which can be assumed to increase the electrical conduction in the composite films.

Electrospun PPY.DBSA/PVA Nanofibers for Ammonium Gas Sensor

Abstract This work presents the results obtained in the production of poly (vinyl alcohol) (PVA) nanofibers with different concentrations of polypyrrole (PPy) doped with dodecylbenzene sulfonic acid (DBSA) - PPy.DBSA. The morphology of the nanofibers was studied by scanning electron microscopy (SEM) technique. The nanofibers were deposited on interdigitated electrodes (IDEs) for direct current electrical characterization (DC) and tested as ammonia gas sensors. The results showed a rapid detection of ammonia gas for higher concentrations of PPy.DBSA and for several alternating cycles in atmospheric N2.

Fabrication and characterization of conductive polypyrrole/chitosan/collagen electrospun nanofiber scaffold for tissue engineering application

Conductive electrospun nanofiber scaffold containing conductive polypyrrole (PPy) polymer was fabricated to accelerate healing of damaged tissues. In order to prepare these scaffolds, various weight percentages of polypyrrole (5, 10, 15, 20, 25%) relative to the polymers combination (chitosan, collagen, and polyethylene oxide) were used. The fabricated composite scaffolds were characterized using chemical, morphological, physio-mechanical, and biological analyses including; FTIR spectroscopy, SEM, electrical conductivity, tensile test, in vitro degradation, MTT Assay and cell culture. The polypyrrole particles were perfectly dispersed inside the nanofibers, and the fibers average diameter were reducing by increasing the polypyrrole content in the composites. The presence of polypyrrole in fibers enhanced their conductivity up to 164.274 × 10−3 s/m which is in the range of semi-conductive and conductive polymers. MTT and SEM analyses displayed that nanofibers composing 10% polypyrrole possess better cell adhesion, growth and proliferation properties comparing to other compositions. Furthermore, the suitable mechanical properties of scaffolds ideally fitted them for different kinds of tissue applications including skin, nerve, heart muscle, etc. Therefore, these fabricated conductive nanofiber scaffolds are particularly appropriate for employing in body parts with electrical signals such as cardiovascular, heart muscles, or nerves.

Development of functional knitted fabrics using yarn composed of polypyrrole coated cotton fibers

This study aimed at developing a knitted fabric using conductive staple spun yarn composed of polypyrrole coated cotton fibers and characterizing its thermal, optical and electrical properties, hydrophobic behavior as well as mechanical stiffness as a factor of weight percentage in fabrics. FTIR spectra, TGA and SEM verify that the polypyrrole ((PPy) has been successfully coated on cotton fibres before and after washing. The results showed that the fabrics containing polypyrrole had lower transmission and reflection percentage as compared with fabric without polypyrrole for wavelengths ranging from 200 to 20000 nm. At the investigated weight percentages, the thermal properties, hydrophobicity and electrical conductivity were found to be increased significantly with increasing amount of polypyrrole coated cotton fibers in the fabric. The thermal conductivity of fabrics with PPy coated fibers were found to be increased around 30-40%. The higher value of electrical conductivity (0.73 µS cm−1) was obtained in course direction and static water contact angle of 138° for fabric with higher polypyrrole content. The stiffness of the fabrics with PPy was found to increase about 10–20% in both wale wise and course wise directions with increase of polypyrrole coated cotton fibers in fabrics.

In-situ polymerization of pyrrole in PVA-PVP matrix: Optimization of oxidant/monomer ratio and its effect on dielectric properties of polymer blend films

Free standing and flexible polymer blend films of PPy (poly pyrrole) doped in PVA (poly vinyl alcohol) – PVP (poly vinyl pyrrolidone) matrix with varying concentrations of PPy have been prepared by solution cast technique at room temperature. In-situ polymerization of pyrrole monomer (Py) in PVA-PVP matrix has been carried out using FeCl3 as oxidant. The effect of monomer amount and monomer to oxidant ratio on the dielectric parameters (such as dielectric constant, dielectric loss, loss tangent, ac conductivity, complex electric modulus, complex impedance) of PPy doped PVA-PVP polymer blend films have been studied in the frequency range of 20 Hz to 2 MHz. Two different molar concentrations (0.15 M and 0.30 M) of oxidants have been taken and for each oxidant concentration, four varying concentrations of monomer have been used to optimize the results. The blend films having oxidant to monomer molar concentration ratio of 0.5 in both the cases (i.e. 0.15 M and 0.30 M) have been found to be smooth, flexible, mechanically strong and easy to process. These films have shown very systematic change and improved values of dielectric parameters within the experimental frequency range. Enhanced dielectric parameters (complex permittivity, ac conductivity and electric modulus) values for films having oxidant to monomer molar ratio of 0.5 suggest the organized growth of PPy chain in the matrix of PVA-PVP.

Structural, Electrical and Thermal Properties of Composites Based on Conducting Polymer

Abstract: In this work, we report the structural, thermal and electrical properties of composites consisting of polypyrrole particles in a polymethylmethacrylate matrix. Electrical resistivity analysis of these percolating composites showed a remarkable change in the conduction mechanisms below and above the percolation threshold. Structural properties were studied using X-ray diffraction, showing increases in the crystallinity index for filler concentrations above the critical percolation. Thermogravimetric analysis was used to study thermal degradation. It shows a transition from a single peak for concentrations below the percolation threshold to a double peak for concentrations above that point. The increase in the degradation temperature with the concentration of polypyrrole indicates the increase of thermal stability. Keywords: Conducting polymer, Percolation threshold, Crystallinity, Thermal degradation, X-Ray diffraction.

Optical parameters of gallium nitride doped ferrite–polypyrrole nanocomposites

Optical parameters of Gallium nitride ferrite and doped polypyrrole nanocomposites (GaNFe2O3–PPY) prepared by using Impregnation technique with different contents of (3%, 10%, 30% by weight) were studied. The gallium nitride ferrite was prepared by sol–gel technique. The UV–Vis characterisation was employed to study the absorption spectra and band gap of gallium nitride ferrite samples and their corresponding nano composites. It was observed that the absorption bands for Gallium nitride ferrite are around ~ 240 nm, ~ 260 nm and ~ 430 nm. For GaNFe2O3–PPY composites the absorption bands are shifted towards the lower wavelength side. The band gap values from Tauc’s plot were calculated and observed that with increase in dopant concentration in Gallium nitride ferrite, there is a decrease in band gap. For nano composites as the concentration of polypyrrole is increased, the band gap is decreased and the wavelength is red shifted. The parameters refractive Index, absorption coefficient, extinction coefficient, optical conductivity, theoretical electrical conductivity, dielectric constant, optical Dielectric constant, metallization criteria and reflectance are studied for all the synthesised samples.

Use of bacterial cellulose film modified by polypyrrole/TiO2-Ag nanocomposite for detecting and measuring the growth of pathogenic bacteria

The aim of this study was to use of bacterial cellulose/polypyrrole/TiO2-Ag (BC/PPy/TiO2-Ag) nanocomposite film to detect and measure the growth of 5 pathogenic bacteria. For this purpose, at first, 13 BC/PPy/TiO2-Ag films were fabricated, then bacterial suspensions were prepared according to McFarland standard. The results showed that by increasing the bacterial concentration, the electrical resistance of sensors was decreased and there was a relation between bacterial concentration and bacterial type with electrical resistance change of sensors. The obtained data showed that the sensitivity of the sensors was increased with increasing the concentration of polypyrrole and TiO2-Ag. FT-IR and SEM tests were performed to investigate the interaction between nanoparticles and determine the size of nanoparticles. The BC/PPy/TiO2-Ag biosensors are portable and the response time of these sensors is very short for target analysis. Therefore, these sensors have the potential to improve biological safety as diagnostic tools.

The inhibitory effects of polypyrrole on the biofilm formation of Streptococcus mutans.

Streptococcus mutans primary thrives on the biofilm formation on the tooth surface in sticky biofilms and under certain conditions can lead to carious lesions on the tooth surface. To search for a new preventive material for oral biofilm-associated diseases, including dental caries, we investigated the effects of polypyrrole, which contains an electrochemical polymer and causes protonation and incorporation of anion under low pH condition, on the biofilm formation of S. mutans and other streptococci. In this study, polypyrrole was applied in biofilm formation assays with the S. mutans strains UA159 and its gtfB and gtfC double mutant (gtfBC mutant), S. sanguinis, S. mitis and S. gordonii on human saliva and bovine serum albumin-coated 96-well microtiter plates in tryptic soy broth supplemented with 0.25% sucrose. The effects of polypyrrole on biofilm formation were quantitatively and qualitatively observed. High concentrations of polypyrrole significantly inhibited the biofilm formation of S. mutans UA159 and S. sanguinis. As an inhibition mechanism, polypyrrole attached to the surface of bacterial cells, increased chains and aggregates, and incorporated proteins involving GTF-I and GTF-SI produced by S. mutans. In contrast, the biofilm formation of gtfBC mutant, S. sanguinis, S. mitis and S. gordonii was temporarily induced by the addition of low polypyrrole concentrations on human saliva-coated plate but not on the uncoated and bovine serum albumin-coated plates. Moreover, biofilm formation depended on live cells and, likewise, specific interaction between cells and binding components in saliva. However, these biofilms were easily removed by increased frequency of water washing. In this regard, the physical and electrochemical properties in polypyrrole worked effectively in the removal of streptococci biofilms. Polypyrrole may have the potential to alter the development of biofilms associated with dental diseases.

Uniformly Embedded Cellulose/Polypyrrole-TiO2 Composite in Sol-Gel Sodium Silicate Nanoparticles: Structural and Dielectric Properties

Modified composites based on cellulose filled with nano-particles of sodium silicate forming cellulose/polypyrrole-TiO2/ sodium silicate nanocomposite were prepared by combining a colloidal sol–gel technique and in-situ oxidative chemical polymerization. The effect of polypyrrole content, processing and the coating by the sodium silicate nanoparticles on the morphology and structure of the prepared composites were studied. The method of processing used was proven to be efficient to uniformly disperse the nano-particles within the polymeric matrix. The dielectric properties, including dielectric constant, $\varepsilon ^{\prime } (\omega )$ , dielectric loss, $\varepsilon ^{\prime \prime }(\omega )$ , tan δ and ac conductivity, σac, of the obtained composites were studied.

Robust self cleaning polypyrrole‐polysulfone blend hollow fiber membrane for biofouling mitigation

AbstractBACKGROUNDPersistent biofouling of membrane is the most commonly encountered problem during separation diminishing the throughput of the system. Many techniques have been adopted to mitigate biofouling. This paper describes the fabrication of polysulfone and polypyrrole blend hollow fiber membrane with outstanding self‐cleaning potential. Blending of polypyrrole promoted excellent anti‐biofouling surface against Gram positive and Gram negative bacteria. The impact of flow rate and pressure on membrane performance was also evaluated during the separation process.RESULTSLoading of polypyrrole resulted in enhanced hydrophilicity, permeability, zeta potential and tensile strength. Scanning electron microscopy confirmed the appearance of macrovoids with increase of polypyrrole concentration, indicating the porous structure of the membrane. Hollow fibers exhibited negative potential at pH 7, leading to excellent anti‐biofouling surface. Roughness of fibers was dramatically reduced from 120 to 3 nm with polypyrrole concentration imparting superior self cleaning surface on the membrane. Fluorescence microscopy analyses revealed significant reduction in bacteria adhesion on 1 wt% polypyrrole loaded fibers. Modified membrane showed striking antibacterial property due to the leakage of cytoplasmic materials through lysis, as supported by A260nm absorption study. Morphological analysis of the used blend membrane showed almost no deposition of bacteria even after a long run, holding the promise of biofouling mitigation.CONCLUSIONModification of membrane by polypyrrole imparted an outstanding self‐cleaning property to the hollow fiber; hence, it is a simple and scalable approach to prevent biofouling during long‐term performance. © 2018 Society of Chemical Industry

Studies on Hysteresis Parameters of gallium nitride doped ferrite/Polypyrrole nanocomposites

We report the role of Polypyrrole in Gallium nitride doped ferrite in Magnetic studies. The concentration of Polypyrrole was changed by 3%,10%,30% in the nano composite that contained 97%,90%,70% by weight of Gallium nitride doped ferrite in the stichiometric equation Ga(2x+2)NFe2(49-x)O3-PPY for x=0.5,0.75. In our studies Saturation Magnetisation is not reached in the Hysteresis loops, also indicates the formation of Wasp-Waists.The parameters of Coercivity, Anisotropy constant, Magnetic moment, squareness ratio and amount of wasp-waistedness are determined from the Hysteresis loops. As the concentration of PPY is changed from 3%,10%,30% Coercivity, Magnetic moment decreased and slight variation in the anisotropy constant values are observed .Sci-finder software is unable to trace reports in the earlier literature in non-Paleo magnetic studies about the Wasp-waists formation. The amount of wasp-waisted ness (HRC/Hc) is evaluated to be 2.1932 for Ga3.5NFe96.5O3-10% PPY. Lower squareness ratio in all synthesized samples indicate Multi-Domain formation.

THE ROLE OF POLYPYRROLE IN ELECTRICAL PROPERTIES OF ZNO-POLYMER COMPOSITE VARISTORS

Composite films on the base of ZnO with different weight percentages of polypyrrole have been prepared using the hot pressing method and their current-voltage characteristics have been studied. Results show that the films have nonlinear varistor behavior and can be used to protect sensitive circuits from 110V up to 350V overvoltages. It is found that the higher the content of polypyrrole in the varistor, the lower the breakdown voltage. Samples with higher polypyrrole content have less nonlinearity. The interesting result is that, unlike semiconductor-polyaniline based varistors, varistor hysteresis decreases through increasing polypyrrole content. Results have been analyzed with respect to SEM micrographs and XRD patterns of the samples. Energy gaps of varistors are evaluated using their UV spectra analysis regarding Tauc relation, which show that increasing polypyrrole content in varistors causes their absorption to increase and the corresponding band gap to decrease.