Polymer Polypyrrole Research Articles

Polypyrrole-intercalation tuning lamellar structure of V2O5·nH2O boosts fast zinc-ion kinetics for aqueous zinc-ion battery

The layered structure of vanadium oxide is an ideal cathode material for aqueous rechargeable zinc-ion batteries (ARZIBs) owing to its tunable structures, high specific capacity and high energy density. It has been shown that the regulation of the layer spacing of the layered vanadium oxide can effectively improve the electrochemical performance of ARZIBs. Most of the literatures have adjusted the layer spacing by chemical pre-insertion of metal ions and the expanded layer spacing is very limited. However, other guests, like polymer, might play a critical role in tuning the lamellar structure of vanadium oxides showing fast Zn-ion kinetics for ARZIBs. Herein, a two-step synthesis is developed to insert the conductive polymer polypyrrole (PPy) into the vanadium oxide layers, resulting in a layer spacing up to 14.0 Å. Large interlayer spacing is beneficial to the rapid (de)intercalation of zinc ions, leading to greatly promote the electrochemical performance of V2O5·nH2O (VOH). The Zn//PPy/VOH battery has an advanced specific capacity up to 383 mAh·g−1 at 0.1 A g−1 and a steady cycle performance. This strategy of pre-insertion of conducting polymer into the host material provides a novel synthesis scheme for the use of vanadium oxide as cathode material for ARZIBs.

Atmospheric pressure plasma treatment for enhancing the conducting properties of polypyrrole coated nylon fabric

AbstractThe present study describes a method for plasma‐assisted in situ chemical polymerization of polypyrrole on nylon‐66 fabric to improve adhesion and conductivity of the polypyrrole coating. Plasma generated from various gas mixtures in dielectric barrier discharge were used to modify the surface of nylon‐66 fabric and investigated the influence of plasma on surface chemistry and morphology of nylon‐66 fabric. Polypyrrole was then deposited over this plasma pretreated nylon fabric by using oxidative chemical polymerization to get electrically conducting nylon fabric. Surface physical and chemical changes of plasma treated nylon‐66 fabric were studied by scanning electron microscopy (SEM), wettability, attenuated total reflection‐Fourier transform infrared spectroscopy (ATR‐FTIR) and X‐ray photoelectron spectroscopy (XPS). Effect of the plasma treatment on binding strength was analyzed by studying abrasion resistance and surface resistivity. Results showed that the strongest interfacial bonding and high conductivity were achieved for He+O2 plasma pretreated PPy coated nylon‐66 fabric. Surface functional groups such as CO, COH, COOH, and CONH were detected on plasma treated nylon‐66 fabric by XPS. These surface functional groups are responsible for the improved adhesion and conductivity of PPY coating on nylon fabric by 35% (up to 2500 abrasion cycles) and 50%, respectively.

Electroactive extracellular Matrix/Polypyrrole composite films and their microenvironmental effects on osteogenic differentiation of BMSCs

Bone marrow mesenchymal stem cells (BMSCs) could be regulated through their microenvironment, which includes biological cues of extracellular matrix (ECM) and other endogenous physical cues. In this work, cell-derived ECM was used as a framework to prepare extracellular matrix/polypyrrole composite films by chemical polymerization of polypyrrole (Ppy). The composite film retained the microstructure of ECM, while the microscopic surface exhibited dual-exposure of ECM and Ppy. The content of Ppy had a decisive influence on the protein exposure area and electrochemical performance to generate different biological or electrical microenvironment. It was worth noting that the ECM/Ppy composite films with appropriate Ppy content had unique biological microenvironments that could promote the osteogenic differentiation of BMSCs. In addition, the electrochemical performance of ECM/Ppy composite films had been significantly improved compared with ECM, which meant that they were electroactive. When BMSCs were simultaneously affected by biological microenvironment and electrical microenvironment, this new composite electroactive film showed the best ability to promote osteogenic differentiation. Correspondingly, the microenvironment provided by ECM/Ppy composite films significantly up-regulated the expression of genes related to osteogenic differentiation of ALP, Col-I, and RunX-2. Furthermore, the electrical microenvironment had been shown to regulate the osteogenic differentiation of BMSCs through the influence on the intracellular calcium ion (Ca2+) concentration and related signal pathways. This new composite electroactive biomaterial has unique biochemical properties and good electrochemical properties to construct biological and electrical microenvironment, having great potential in research and application of bone tissue regeneration and regenerative medicine.

Direct-Ink-Write Printing and Electrospinning of Cellulose Derivatives for Conductive Composite Materials.

The aim of this study is to realize the controlled construction and modulation of micro-/nanostructures of conductive composite materials (CCMs) in a facile way. Herein, interdigital electrodes are prepared by direct-ink-write printing co-blended inks made of ethyl cellulose and carbon nanotubes on cellulose paper. The cellulose nanofibers (CFs) are prepared by electrospinning cellulose acetate on to an aluminum foil, followed by deacetylation in NaOH/ethanol. All co-blended inks exhibit a typical non-Newtonian shear thinning behavior, enabling smooth extrusion and printing. The above electrodes and the conductive CF films with excellent thermal stability are assembled into a pressure sensor, which has a high sensitivity (0.0584 KPa−1) to detect the change in external loading pressure. The obtained porous CFs film is further endowed with conductivity by in situ polymerization of polypyrrole (PPy), which are uniformly distributed on the CFs surface as particles; a triboelectric nanogenerator is constructed by using the CF@PPy film as a tribo-positive friction layer to achieve efficient energy harvesting (output voltage = 29.78 V, output current = 2.12 μA). Therefore, the construction of CCMs with micro-/nanostructures based on cellulose derivatives have essential application prospects in emerging high-tech fields, such as green electronics for sensing and energy harvesting.

Kinetics and characterization of preparing conductive nanofibrous membrane by In-situ polymerization of Polypyrrole on electrospun nanofibers

Polypyrrole (PPy) is a conductive polymer that can be fabricated into various structures via in-situ polymerization for different applications. However, a kinetics study of its in-situ polymerization is needed for a better understanding of the mechanisms of pyrrole polymerization. This paper develops two different kinetics models based on existing PPy polymerization mechanisms. The most suitable mechanism is first identified by comparing the model results with experimental data. Then, in-situ polymerizations of PPy on electrospun fibrous polyacrylonitrile (PAN) templates were produced at temperatures ranging from 273 to 285 K. The results show that the overall reaction rate of the in-situ polymerization process in the presence of electrospun fibrous template is faster than that without the template. Further investigation confirms that the increase in the overall reaction rate is attributed to the enhanced reactions between oxidized pyrrole oligomers and neutral pyrrole monomers, as the corresponding reaction rate constant and activation entropy increased by 158.2–209.6% and 37.7%, respectively. The reason is that the considerable number of available reaction sites between oxidized oligomers and neutral monomers are created by the fibrous template. In addition, the composite membrane obtained from the in-situ polymerization exhibited well-developed fibrous nanostructure, good electrical conductivity (0.29 ± 0.04 S∙m−1), sufficient mechanical strength (UTS of 8.7 MPa) and relatively stable thermal properties (up to 250 °C).

One-pot synthesis of conductive polypyrrole incorporated ZIF-67 for high- performance supercapacitors

The poor electrical conductivity of the metal organic frameworks (MOFs) limits their application in the supercapacitors. Here we developed a versatile strategy to effectively incorporate the conductive polymer polypyrrole (PPy) into ZIF-67 by in-situ polymerization and crystallization. Attributed to the stereoscopic surrounding of ZIF-67 with the conductive PPy, which is helpful for fast transfer of the electron/ion, the ZIF-67/PPy heteroaerogel exhibits a high specific capacity (1241F g−1 at 1A g−1) and high stability with 91% retention rate after 10,000 cycles measurement at 10 A g−1. The appealing electrochemical performance of the ZIF-67/PPy heteroaerogel recommends its promising application in supercapacitors.

Investigation on the effect of in-situ growth of PPy on structural, thermal and dielectric properties of PVA-CMC blend films

ABSTRACT The intrinsic conducting polymer (ICP) Polypyrrole (PPy) was grown in situ in the matrix of polyvinyl alcohol (PVA)-Sodium carboxymethyl cellulose (CMC) using chemical oxidative polymerization method. The effect of in-situ growth of PPy on structural, morphological, thermal and dielectric properties of PVA-CMC blend films were investigated. Growth of PPy in the matrix of PVA-CMC was seen in SEM micrographs along with structural modifications which were confirmed by XRD and FT-IR analysis suggesting the amorphous nature of PVA-CMC-PPy blend films. Thermal analysis suggests good miscibility and compatibility of the polymers in the blend. The changes in the dielectric properties of in-situ-grown conducting polymer blend films of PVA-CMC-PPy were studied in detail at low frequency (100 Hz to 2 MHz) . Enhancement in the dielectric constant and ac conductivity values of PVA-CMC- PPy films were observed in this frequency range that is related to increased amorphousness and formation of conductive channels due to the presence of PPy. Further, the microwave absorption and dielectric behavior of PVA-CMC-PPy films in high-frequency region (200 MHz – 20 GHz) were specially studied to see the suitability of these films for EMI shielding application.

Electrically conductive nanocomposites produced by in situ polymerization of pyrrole in pre‐vulcanized natural rubber latex

AbstractFlexible conductive polymeric nanocomposites were produced by in situ polymerization of polypyrrole (PPy) in a natural rubber (NR) latex medium. Pre‐vulcanized and non‐pre‐vulcanized NR latex, with varying NR/pyrrole (Py) monomer ratio was studied. The resulting nanocomposites were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, DC electrical conductivity, and mechanical properties. The electrical conductivity increased as the NR/Py ratio decreased reaching a maximum of 1.0 × 10−2 S/cm for a vulcanized nanocomposite with NR/PY = 4 mass ratio. In terms of mechanical properties, it was observed that tensile strength at break (σatbreak) also increased with decreasing of NR/Py mass ratio, and for the same proportion of Py, the nanocomposites obtained from vulcanized latex presented higher strength. SEM analysis revealed that unlike non‐pre‐vulcanized latex, PPy nanoparticles tend to be distributed in the pre‐vulcanized matrix in circumferential patterns, with an average diameter of 1 micron, indicating that the rubber microparticles have been encapsulated by the conductive polymer. This engineered morphological structure has been shown to significantly influence the final properties of the nanocomposites, compared to those prepared from non‐vulcanized latex, changing not only the distribution of PPy in the matrix, but also changing the coalescence behavior of NR particles, as well as influencing the percolation threshold.

Magnetic graphene molecularly imprinted polypyrrole polymer (MGO@MIPy) for electrochemical sensing of malondialdehyde in serum samples

A modified screen-printed carbon electrode (SPCE) has been designed and fabricated for the determination of malondialdehyde (MDA), an important biomarker of oxidative stress. Magnetic graphene oxide (MGO) was synthesized and coated by a molecularly imprinted polypyrrole (MIPy) for the preparation of a novel hybrid nanomaterial (MGO@MIPy). The nanocomposite has been characterized using different spectroscopic and imaging techniques. The coupling of MIPy with MGO allows the exploitation of the magnetic properties of the material for separation, preconcentration and manipulation of analyte which is selectively captured onto the MIPy surface of the nanocomposite. Besides, the derivatization of MDA with diaminonaphtalene (DAN) was carried out, resulting in a more electroactive molecule (MDA-DAN). MDA-DAN was used as template in the synthesis of MIPy. SPCEs were employed to monitor the differential pulse voltammetry (DVP) levels of the material, which is related to the amount of the captured analyte. Under optimum conditions, the nanocomposite-based sensing system has proved to be suitable for the monitoring of MDA, presenting a wide linear range (0.01–100 µM), high sensitivity (experimental LOQ = 0.01 µM) and precision (RSD = 4%). For validation purposes, three chicken serum samples were analysed by external calibration, obtaining recoveries values close to 100% for all the spiked tests. Finally, the developed electrochemical sensor demonstrated to be adequate for bioanalytical application, presenting an excellent analytical performance for the routine monitoring of MDA in serum samples.

Flexible conductive silk-PPy hydrogel toward wearable electronic strain sensors

Conductive hydrogels have been studied as promising materials for the flexible and wearable bioelectronics, because of their unique electrical and mechanical properties. Addition of conducting polymers in biomaterial-based hydrogel matrix is a simple yet effective way to construct hydrogels with good conductivity and flexibility. In this work, a conductive hydrogel composed by a silk hydrogel and a conducting polymer, polypyrrole (PPy), is developed via in situ polymerization of pyrrole into the silk fibroin network. The silk-PPy hydrogel shows high conductivity (26 S m−1), as well as sensitive and fast responses to corresponding conformation changes. Taking advantages of these properties, flexible and wearable strain sensors are proposed for the monitoring of various body movements, which can detect both the large and subtle human motions with good sensitivity, reproducibility and stability. The hybridization of biomaterials and conducting polymers endows the multifunctions of the conductive hydrogels, thus showing considerable potentials in the advancement of the wearable electronics.

Enhancing Thermoelectric Properties of Conductive Polymers Using Zr-Metal-Organic Frameworks Composite Materials

Controlling the polymerization of polypyrrole (Ppy) in presence of Zr-based metal organic-framework (Zr-MOFs) using sodium dodecyl sulphonate (SDS) as a dopant, leads to the formation of a new class of thermoelectric materials based on conducting polymer and highly porous MOFs with enhanced properties for energy production applications. The polymerization of polypyrrole in the Zr-Fumerate pores leads to the formation of homogenously coated MOF-spheres with high crystalinity and a high degree of improvement in many electrical properties such as conductivity and carrier mobility. The figure shows the movement of the electrons from the hot to the cold side in the aligned polymer inside the MOF pores.

Improving UV Light Photocatalytic Activity of WO3 by Doping with Boron and Compounding with Polypyrrole

Tungsten oxide (WO3) and boron-doped WO3 (WO3-B) nanoparticles were synthesized using the co-precipitation technique. In addition, as-prepared photocatalysts were compounded with a conducting polymer, polypyrrole (PPy), to prepare PPy/WO3 and PPy/WO3-B composites. The photocatalytic activity of pure WO3, WO3-B, and the PPy composites for decomposing an organic dye, methylene blue, was compared. Doping with boron atoms and/or compounding with polypyrrole improved the photocatalytic performance of WO3, which was probed by performing UV-Vis absorption spectroscopy. The boron doping improved the photocatalytic performance of the WO3 nanoparticles, which was ascribed to reducing the recombination rate of the photoinduced charge carriers and the increase in the number of photogenerated holes on WO3 upon UV light irradiation. Compounding WO3 with polypyrrole enhanced the photocatalytic activity, which was also assigned to the decrease in the recombination rate of the photoexcited charge carriers.

Amperometric room temperature hydrogen gas sensor based on the conjugated polymers of polypyrrole–polyethylene oxide nanofibers synthesised via electrospinning

Amperometric room temperature hydrogen gas sensor based on the conjugated polymers of polypyrrole–polyethylene oxide nanofibers synthesised via electrospinning

Flexible conductive silk-PPy hydrogel toward wearable electronic strain sensors.

Conductive hydrogels have been studied as promising materials for the flexible and wearable bioelectronics, because of their unique electrical and mechanical properties. Addition of conducting polymers in biomaterial-based hydrogel matrix is a simple yet effective way to construct hydrogels with good conductivity and flexibility. In this work, a conductive hydrogel composed by a silk hydrogel and a conducting polymer, polypyrrole (PPy), is developed via in-situ polymerization of pyrrole into the silk fibroin network. The silk-PPy hydrogel shows high conductivity (26 S/m), as well as sensitive and fast responses to corresponding conformation changes. Taking advantages of these properties, flexible and wearable strain sensors are proposed for the monitoring of various body movements, which can detect both the large and subtle human motions with good sensitivity, reproducibility and stability. The hybridization of biomaterials and conducting polymers endows the multifunctions of the conductive hydrogels, thus showing considerable potentials in the advancement of the wearable electronics.

Largely enhanced adsorption performance and stability of MXene through in-situ depositing polypyrrole nanoparticles

Due to the high presence of active functional groups, two-dimensional transition metal carbide/nitride materials that are usually named MXene have been thought as an efficient adsorbent for the removal of organic contaminants from wastewater. However, the poor stability of MXene originated from the high oxidization performance greatly restricts their application. In this work, few-layered MXene was firstly prepared and then the in-situ polymerization of polypyrrole (PPy) was induced in the MXene solution to prepare the MXene/PPy composite particles. The microstructure, adsorption behaviors toward methylene blue (MB) and the stability during the storage process were systematically investigated. The results show that introducing PPy nanoparticles promotes the further exfoliation of MXene. Consequently, the adsorption ability of the MXene/PPy composite particles is significantly enhanced, and the maximum adsorption capacity reaches 553.57 mg/g. The MXene/PPy composite particles also show high adsorption selectivity and it can exclusively remove MB from the solution mixing both cationic and anionic dyes simultaneously. The stability of the MXene is greatly enhanced and nearly no oxidization is observed for the MXene/PPy composite particles. This study offers an additional way to fabricate the MXene-based adsorbents with high stability, and the composite particles exhibit promising applications in effluent water remediation.

Polypyrrole-coated recycled polyphenylene sulfite nonwoven fabric with high electrical conductivity for heat generation

In order to introduce multifunctional properties into the recycled polyphenylene sulfite (PPS) nonwoven fabrics, highly conductive and hydrophobic fabrics with excellent Joule heating performance were fabricated by depositing in-situ polymerized polypyrrole (PPy) onto PPS nonwoven fabric and followed by a silicone coating process. The resultant PPy-coated nonwoven fabric exhibited high electrical conductivity. The surface resistivity of PPy-coated nonwoven fabric was less than 8.8 Ω/sq. The high conductivity of PPy coating provided the fabric with excellent electrical heating properties in conjunction with a photothermal heating properties. The saturation temperature of the samples can get to 125.6°C with 4V DC power. The thin silicone coating can help to resist the oxidation of PPy and endow the nonwoven fabrics with excellent water-resistant features. This study provided a simple and effective method to transform the recycled PPS nonwoven fabric into a multifunction material.

Conducting polymer hydrogels with electrically-tuneable mechanical properties as dynamic cell culture substrates

Hydrogels are a popular substrate for cell culture due to their mechanical properties closely resembling natural tissue. Stimuli-responsive hydrogels are a good platform for studying cell response to dynamic stimuli. Poly(N-isopropylacrylamide) (pNIPAM) is a thermo-responsive polymer that undergoes a volume-phase transition when heated to 32 °C. Conducting polymers can be incorporated into hydrogels to introduce electrically responsive properties. The conducting polymer, polypyrrole (PPy), has been widely studied as electrochemical actuators due to its electrochemical stability, fast actuation and high strains. We determine the volume-phase transition temperature of pNIPAM hydrogels with PPy electropolymerised with different salts as a film within the hydrogel network. We also investigate the electro-mechanical properties at the transition temperature (32 °C) and physiological temperature (37 °C). We show statistically significant differences in the Young's modulus of the hybrid hydrogel at elevated temperatures upon electrochemical stimulation, with a 5 kPa difference at the transition temperature. Furthermore, we show a three-fold increase in actuation at transition temperature compared to room temperature and physiological temperature, attributed to the movement of ions in/out of the PPy film that induce the volume-phase transition of the pNIPAM hydrogel. Furthermore, cell adhesion to the hybrid hydrogel was demonstrated with mouse articular chondrocytes.

Dissolvable conducting polymer supercapacitor for transient electronics

This work explores the use of a conducting polymer that can dissolve in mild aqueous conditions as a supercapacitor material for applications in transient electronics, biomedical devices, and biodegradable energy storage. A repeating polymer of methyl 1H-pyrrole-3-carboxylate monomer (“MPC polymer”) is prepared via electrochemical and chemical polymerization methods, and tested for the first time as a supercapacitor energy storage material. The MPC polymer exhibits charge storage performance comparable to pseudocapacitive conducting polymer polypyrrole (PPY), both as a planar electrode and as a composite porous electrode with poly (l-lactic acid) (PLLA). Chronoamperometry charge-discharge results indicate that the MPC polymer stores energy as a pseudocapacitive material following a faradaic current model. Electrochemical impedance spectroscopy (EIS) measurements demonstrate that MPC polymer electrodes have lower equivalent series and charge transfer resistance compared to PPY electrodes. Cycle life testing of MPC polymer and PPY electrodes shows equal capacitance loss for both electrodes over 1100 cycles. After use as a supercapacitor electrode with an organic electrolyte, MPC polymer-based electrodes showed visible signs of degradation in a mild aqueous environment (37 °C, pH 8.2) in 8 h.

Electrically conductive foams via high internal phase emulsions with polypyrrole-modified carbon nanotubes: Morphology, properties, and rheology

Electrically conductive polystyrene/carbon nanotube (CNT) microcellular foams were prepared via a high internal phase emulsion (HIPE) polymerization technique. To improve the electrical conductivity of the microcellular foams and the chemical affinity with the oil phase of HIPEs, CNTs were modified with a conductive polymer, polypyrrole (PPy). The dispersibility and performance of the PPy-modified CNTs (PPy-CNTs) in the foams were evaluated by the morphology, electrical conductivity, compression properties, and rheological properties. The dispersion and intrinsic properties of PPy-CNTs with respect to the ultrasonic intensity and time were confirmed by the morphology and electrical conductivity of the foams. As the PPy-CNT content increased, the cell size of the foams decreased, while the electrical conductivity increased. The electrical percolation threshold of PPy-CNT in the microcellular foams was as low as 0.23 wt% (w.r.t. dry foam) owing to the excellent dispersion of CNTs coated with the conductive polymer. The incorporation of PPy-CNTs significantly affected the rheological properties of the emulsions. As the PPy-CNT content increased, the yield stress and storage modulus increased, indicating that the emulsion gradually changed into a solid-like material. The crush strength of the foams increased with the PPy-CNT content and agitation speed.

Performance of room-temperature activated tubular polypyrrole modified graphite felt composite electrode in vanadium redox flow battery

In this paper, the graphite felt (GF) composite electrode modified with the conducting polymer of tubular polypyrrole (PPy) was prepared at room temperature with the advantages of low-energy and acid free synthetic process. The material characteristics and electrochemical properties of PPy power and PPy modified GF composite electrodes (PPy-GF) were studied by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV) tests, electrochemical impedance spectroscopy (EIS) analysis, and charge-discharge tests. The vanadium redox flow battery (VRFB) assembled with room-temperature activated PPy-GF electrode exhibits improved performance with the energy efficiency (EE) up to 82.20% at the current density of 80 mA•cm−2, which is 6.10% and 4.02% higher than that with Pristine GF and Air heated GF, respectively. Moreover, the cell equipped with the composite electrode treated in 2 mg/mL PPy solution shows the highest discharge capacity of 724.4 mA•h and superior cycling stability after 100 cycles.