Polymer Polypyrrole Research Articles

Synergistic Effect of Polypyrrole-Polyaniline Conducting Polymer Nanocomposite and Fe3O4 Nanoparticles for Arsenite (III) Adsorption from wastewater

For treatment of arsenic contaminated water, adsorption of arsenic and it’s reduction are there important processes. Conducting polymer efficiently show the efficient absorption but in use of it there is agglomeration of particles which make its usage difficult. To reduce this problem magnetic property material are used. In this polypyrrole and polyaniline conducting polymers were used. By oxidative polymerization of Polypyrrole and aniline in presence of Fe3O4 by utilizing FeCl3 nanocomposite was manufactured. In this magnetite prevented the agglomeration of particles of polymers and also helped in separation of nanocomposite from solution. Characterization was done by FTIR, SEM and XRD. This nanocomposite removal 88% arsenide (III) from aqueous solution at adsorbent concentration 0.01g and pH=1. Colorimetric method was used which developed complex with arsenite (III) and showed the removal of arsenite (III) from aqueous solution by complex. Separation of nanocomposite became easy due to magnetic properties of magnetite. This could be isolate from aqueous solution by using of strong magnet. This nanocomposite is the promising composite for removal of arsenite (III) from aqueous solution.

Lightweight Nanofiber‐Reinforced Pyrrole‐Reduced Graphene Oxide Aerogel for Pressure Sensor and Oil/Water Separation Material

AbstractThe mechanical brittleness of graphene aerogel becomes the main defect that restrains their multifunctional application due to the strong π–π stacking and Van der Waals forces between graphene nanosheets. Herein, a novel and simple 1D nanofiber‐reinforced 2D pyrrole‐reduced graphene oxide (GO) to construct a 3D graphene aerogel (GA) is developed. The pyrrole effectively reduces GO to graphene and the in situ polymerized polypyrrole (PPy) can improve the conductivity of GA. Benefiting from the synergistic reinforcement of cellulose acetate (CA) electrospun nanofiber and crosslinker PPy on the graphene framework, the lightweight GA exhibits satisfactory mechanical properties. The assembled flexible piezoresistive sensor shows a high sensitivity of 32.39 kPa−1 and a wide detection range of up to 65.3 kPa, which can be able to withstand more than 10 000 loading‐unloading cycles. It has a broad application prospect in human motion and health signal monitoring as a high‐performance wearable pressure sensor. Particularly, the porous GA is also proved to be a high‐efficiency oil/water separation material with a strong adsorption capacity (56.9–115.2 g g−1) for various oils and organic solvents.

Polypyrrole nanoparticles loaded with doxorubicin for pH-responsive combinational photothermal-chemotherapy of cancer cells

The combined treatment method integrated photothermal therapy (PTT) with chemotherapy is extremely promising owing to the synergistic therapeutic effect as compared to single PTT or chemotherapy. To facilitate more novel and facile photothermal-chemotherapy drugs as well as promote controllable combination therapy, we have developed a mild and facile method to fabricate polymer polypyrrole (PPy)-doxorubicin (DOX) nanoparticles (NPs) as pH-responsive drug nanocarriers for synergistic photothermal-chemotherapy. In the nanoplatform, poly-L-lysine (PLL)-modified PPy serves as the photothermal material, and (DOX) molecules are adopted as the chemotherapy agent. Based on the cross-linking reaction of glutaraldehyde, DOX molecules are flexibly and efficiently assembled on the surface of PLL-modified PPy NPs. The obtained PPy-DOX NPs possess high photothermal effect, superior loading capacity of DOX, and controlled drug release behavior. The combination photothermal-chemotherapy based on PPy-DOX NPs has significantly enhanced the antitumor therapy effect. In general, the designed PPy-DOX NPs may be a potential drug delivery nanoplatform for cancer combination therapy.

Resilient and Tough Conductive Polymer Hydrogel for a Low-Hysteresis Strain Sensor.

Conductive polymer hydrogels are vital in strain sensors, yet achieving high resilience and toughness is a challenge. This study employs a prestretch method to engineer a tough conductive polymer hydrogel with sufficient resilience. Initially, a blend film of polyvinylalcohol (PVA) and ethylene-vinyl alcohol copolymer (EVOH) is prepared through solution casting, followed by a swelling process to form a PVA-EVOH hydrogel. This hydrogel, with PVA crystallites as crosslinking points, exhibits high toughness. The hydrogel is then immersed in pyrrole and ferric chloride solutions for in-situ polymerization of polypyrrole (PPy), creating a conductive PPy/PVA-EVOH hydrogel. Finally, a 200% prestretch is applied, breaking short chains within the network, eliminating energy dissipation at low strains. This results in a hydrogel with a 100% elastic deformation range, while maintaining high fracture toughness (1700Jm-2 ). The prestretched PPy/PVA-EVOH hydrogel functions as a strain sensor with low hysteresis, providing consistent strain measurements during loading and unloading. This outperforms the non-prestretched sample, which shows inconsistent responses between stretching and releasing.

Sponge-like biodegradable polypyrrole-modified biopolymers for selective adsorption of basic red 46 and crystal violet dyes from single and binary component systems

Recently, several researchers have been trying to reduce the ecological effects of water pollution by considering the use of biodegradable materials that prevent the generation of secondary pollution in our environment and enable water reuse. Here, new biodegradable hydrogels based on alginate (Alg), gelatin (Gel) and polypyrrole (PPy) were successfully implemented to remove two known highly toxic cationic dyes from wastewater. The design process was performed in two steps: in-situ polymerization of polypyrrole within the Alg/Gel mixture, followed by hydrogel formation. Biocomposites showed promising efficacy for the removal of both basic red 46 (BR46) and crystal violet (CV) dyes from real and demineralized water samples. However, Alg-Gel-PPy hydrogel showed better selectivity for BR46 than for CV as compared to the pristine Alg-Gel hydrogel. Adsorption of both pollutants on biocomposite hydrogel beads followed the Langmuir isotherm and pseudo-second order kinetic models. Besides, the highest adsorption capacities (125 mg g−1 for BR46 and 88.5 mg g−1 for CV) were obtained for the Alg-Gel-PPy hydrogel, compared with those determined for PPy-free hydrogel (103.09 mg g−1 for BR46 and 86.96 mg g−1 for CV) and remained at a satisfactory level for five adsorption-desorption cycles. Finally, the obtained hydrogels showed excellent biodegradability by natural soil microorganisms, with 91 % decomposition.

Bio-based phytic acid-induced polypyrrole/silver nanowires coating towards multifunctional nylon/cotton blend fabrics

The functional flexible wearable textiles have a broadapplicationprospect in many areas. However, considering the physical and chemical effects among various additives, it is still a big challenge to prepare wearable fabrics with a balance between different properties. Herein, an eco-friendly and multifunctional nylon/cotton blend fabric was constructed by phytic acid (PA)-induced polymerization of polypyrrole on the surface, followed by dip coating with silver nanowires (AgNWs). A high electrical conductivity of the treated blend fabrics (61 S·m−1) was obtained contributed to the excellent EMI shielding performance of nylon/cotton blend fabric (X-band ∼ 38.8 dB). Meanwhile, the coating maintained the surface temperature of the fabric within a suitable range, resulting in achieving the efficient thermal management. Furthermore, the treated nylon/cotton blends achieved a remarkable reduction (83.3 % and 81.7 %) of peak heat release rate and total smoke production compared to that of the control nylon/cotton blends. In addition, the considerable antibacterial property against E. coli and S. aureus was also realized. The successful application of this simple and eco-friendly method offered the possibility of preparing safer and more versatile wearable smart textiles.

Highly Electroactive Frozen-State Polymerized Polypyrrole Nanostructures for Flexible Supercapacitors.

The polymerization of pyrrole in the frozen state with the presence of organic dyes (methyl orange (MO) and Acid Blue 25 (AB)) has proven to produce polypyrrole (PPy) nanostructures. Herein, we explore the electrochemical properties of PPy prepared under frozen-state conditions (-24 °C) with and without the presence of organic dyes. The electroactivity of PPy prepared with MO and AB significantly increased in all electrolytic media with a capacitance higher than this of the PPy prepared at room temperature. The highest capacitance (1914 F g-1) was obtained for PPy-MO in 0.2 M HCl solution. The impedance spectra of PPy showed a decrease in charge transfer resistance when the dyes were present. This indicates a conductivity increase of PPy. Improved electrochemical stability was observed for PPy, PPy-MO, and PPy-AB prepared at -24 °C, wherein a steady gain of capacitance was maintained during 5000 potential cycling. In addition, a PPy-based supercapacitor device was fabricated to demonstrate the energy storage characteristics of PPy, where it showed good capacitive behavior and stability. Overall, frozen-state polymerized PPy posed an impressive capacitive performance for flexible supercapacitors.

Improving activity and barrier properties of epoxy modified polyurethane coating with in-situ polymerized polypyrrole functionalized graphene oxide

The limited dispersibility and lack of active anti-corrosion properties of graphene oxide (GO) have hindered its application in corrosion resistance. In this study, we graft the corrosion inhibitor benzotriazole (BTA) on the surface of GO to achieve pH response release, providing active corrosion protection for epoxy modified polyurethane (EP-PU) coating. An environmentally friendly composite material with a sandwich-like structure was synthesized by in-situ polymerization of pyrrole to improve GO dispersion and prevent rapid release of BTA. The electrochemical impedance spectroscopy (EIS) shows that adding 0.15% GBP enhances the coating's anti-corrosion performance. The dual functions of passive and active corrosion enable the GBP/EP-PU coating to provide long-term corrosion protection for metal substrates.

Biomimetic scale-like polysaccharide-based highly-sensitive piezoresistive sensor with “shell-core” nanostructure

A nanofiber membrane is an ideal carrier for constructing a typical three-dimensional conductive network. Inspired by the biomimetic scale-like nanostructure, polysaccharide-based piezoresistive material with outstanding Joule heating performance, thermal efficiency, and high conductivity is developed, presenting a potential indicator material with the color shifting function for intelligent skin or soft robots in practical applications. The stable core-shell structure due to the in-situ polymerization of polypyrrole (PPy) on the electrospun nanofiber endows the piezoresistive sensor (s-PGG@PPy) with a broad pressure range (0.13–128.46 kPa), high sensitivity (52.42 kPa−1) and fast response time (26 ms). The free motion of π electrons along the nanofibers between carbon atoms perfectly made it an attractive candidate for real-time monitoring of human activities, including bending of fingers, wrist, knee, and facial expression. In addition, designing s-PGG@PPy is to be connected in parallel and composed of an indication function glove, which shows different brightness with finger pressure. Consequently, the reported piezoresistive sensor represents a potential for wearable bioelectronics.

Synthesis and Application of Polypyrrole/DBSA/Boron Nitride Ternary Composite as a Potential Chemical Sensor for Ammonia Gas Detection

The present study demonstrates the self-assembly method of chemical oxidative polymerization of polypyrrole (PPy), polypyrrole/boron nitride (PPy/BN), and polypyrrole/dodecylbenzene sulfonic acid/boron nitride (PPy/DBSA/BN) thin films for ammonia (NH3) gas detection. The PPy, PPy/BN, and PPy/DBSA/BN thin films were comprehensively characterized using Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), X-ray diffractometry (XRD) and conductivity measurement. ATR-FTIR revealed all the pertinent peaks of PPy, BN, and DBSA present in the PPy/DBSA/BN. SEM images of PPy/DBSA/BN depict well-organized morphology. PPy/DBSA/BN recorded the highest conductivity of 4.771 x 10-6 S cm-1 among the prepared polymer thin films. The obtained characterization results are in good agreement with the NH3 gas sensor measurements conducted on the PPy/DBSA/BN composite. The linear correlation coefficient between the two was found to be R2 = 0.9916, indicating a strong relationship. Furthermore, the PPy/DBSA/BN thin film demonstrated a low limit of detection (LOD) of 5.8 ppm, surpassing the OSHA threshold value for NH3 gas. This suggests that the sensor is highly sensitive to trace amounts of NH3 gas. Moreover, the PPy/DBSA/BN thin film exhibited exceptional reusability, with the ability to be used for up to 10 cycles without a significant decrease in performance. The sensor also demonstrated selectivity towards NH3 gas in the presence of common interfering species. Additionally, it exhibited long-term stability, maintaining its performance over a period of 7 days. The proposed self-assembled gas sensor has showcased remarkable performance in detecting NH3 gas at room temperature, making it a promising candidate for industrial applications.

A Free-Standing Polymer Polypyrrole/Cellulose Composite Film via Spatial-Confined Interfacial Electrodeposition for Flexible Supercapacitors.

As a kind of energy storage device, a flexible supercapacitor has the characteristics of high capacity, fast charge/discharge rate, good stability, portability and softness. Conductive polymer polypyrrole (PPy) can be used as an electrode material for supercapacitors due to its environmental friendliness, simple synthesis process, good conductivity and potential for large-scale production. However, pristine PPy inevitably suffers from structural rupture due to repeated doping/de-doping during charge and discharge processes, which in turn impairs its cycle stability. In general, compounding with flexible substrates like soft carbon materials, cellulose or nylon fabric, is a good strategy to weaken the inner stress and restrain the structure pulverization of PPy. Herein, cellulose is utilized as a soft substrate to compound with PPy based on the electrochemical oxidation of polypyrrole. The interfacial electrodeposition method can successfully obtain a smooth, uniform and flexible PPy/cellulose composite film, which shows good conductivity. The assembled symmetric supercapacitor with PPy/cellulose film has an optimized specific capacitance of 256.1 mF cm-2, even after 10,000 cycles at a current density of 1 mA cm-2. Furthermore, there is no significant capacitance loss even after 180° bending of the device. This work provides a new means to prepare flexible, low-cost, environmentally friendly and high-performance electrode materials for energy conversion and storage systems.

Construction of oxygen-vacancy-rich Z-scheme polypyrrole/Bi2SiO5 heterojunction for efficient degradation of antibiotics under simulated sunlight

A Z-scheme polypyrrole/Bi2SiO5 heterojunction rich in oxygen vacancies was prepared by combining the organic polymer polypyrrole with Bi2SiO5 via a hydrothermal method and an oxidative polymerization reaction. The photocatalyst exhibited good stability in water and effectively degraded tetracycline, oxytetracycline, ciprofloxacin, norfloxacin, and doxycycline under simulated sunlight, indicating its excellent potential for wastewater treatment. In particular, the efficiency of tetracycline removal by the optimized polypyrrole/Bi2SiO5 composite after 120 min of irradiation was 93.1%, approximately 2.1 times that of Bi2SiO5. The exceptional photocatalytic performance of polypyrrole/Bi2SiO5 stemmed from the construction of a Z-scheme heterostructure and generation of oxygen vacancies induced by the introduction of polypyrrole. Furthermore, liquid chromatography–mass spectrometry (LC-MS) was used to investigate the intermediate products of tetracycline degradation, and possible degradation pathways were deduced. Finally, a possible photocatalytic mechanism was proposed based on the results of electron paramagnetic resonance and free radical capture experiments.

Polypyrrole- and Polyaniline-Coated Cotton Fabrics as Efficient Adsorbents for the Pharmaceutical Water Contaminants Diclofenac and Salicylic Acid.

The emerging pharmaceutical contaminants diclofenac (DCF) and salicylic acid (SA) pose potential hazards to humans and living organisms due to their persistence in water environments. In this work, the conductive polymers polypyrrole (PPY) and polyaniline (PANI) were successfully coated on cotton fabrics, as confirmed by FTIR and SEM measurements. The coated fabrics efficiently removed DCF at pH 5.3 and SA at pH 4, with removal efficiencies that exceeded 90% and 70%, respectively. Adsorption was rapid for most of the tested contaminant-fabric systems and reached equilibrium within 20-30 min. The best adsorption performance for both contaminants was shown on the PPY-coated fabrics, which yielded adsorption capacities of about 65 and 21 mg/g for DCF and SA, respectively. This could be explained by molecular modeling simulations, which mostly estimated higher total cohesive energy densities for adsorption on the PPY-coated fabrics than on the PANI-coated ones. The adsorption mechanism involved both coulombic electrostatic attractions and non-coulombic van der Waals and π-π stacking. The fabrics could be reused for three adsorption-desorption cycles. Immobilization of the conductive polymers on cotton fabrics provides a facile method for their handling and collection during adsorption and regeneration cycles while maintaining their multi-functionality in adsorbing different contaminants.

A Lightweight and Low-Voltage-Operating Linear Actuator Based on the Electroactive Polymer Polypyrrole.

In recent decades, significant research efforts have been devoted to studying various types of actuators. Of particular interest are soft actuators based on electroactive polymers, which offer low operating voltage, light weight, and fast response. In this study, we demonstrate the feasibility of a soft linear actuator fabricated from polypyrrole (PPy), an electroactive polymer that is easy to synthesize, cost-effective, and biocompatible. By optimizing the polymerization conditions, the operation condition and environment, we were able to achieve improved and stable actuator performance. Furthermore, we developed a new actuator-contained component with a flexible counter electrode to build an actuator that operates in air. This approach enabled us to build small and lightweight actuators that operate in air, with a diameter of 5 mm, resembling artificial muscles. Our resulting miniaturized and integrated linear PPy-based actuators can be driven at low voltages (±1.5 V), making them suitable for use in various parts of the body. As such, this actuator holds significant potential for a wide range of applications in the fields of soft electronics, drug delivery, artificial organs, and muscles, as well as a component material for portable medical sensors and devices.

Preparation and study of Nanocomposite material CAFe-PPy

Carbon aerogel (CA) is a new type of lightweight porous material with many excellent properties. Here, CAFe-PPy was prepared via iron and conductive polymer polypyrrole (PPy) on carbon aerogel. The physical properties of CA and CAFe-ppy were compared. Iron, nitrogen and oxygen were successfully loaded onto CAFe-PPy. PPy can increase the conductivity of CAFe-PPy, but it also blocks some holes.

Neural regeneration ability of Polypyrrole-Collagen-Quercetin composite in the spinal cord injury

Spinal cord injury (SCI) is a major clinical problem in young patients. The major hurdle in SCI regeneration is the replacement of lost nerve communication signals due to injury. Here we have prepared a biocompatible electrical conductive composite such as Collagen-Polypyrrole combined with Quercetin (Col-PPy-Qur) composite. The prepared composites are characterized for their chemical functionality and morphology by the FTIR and SEM & TEM analysis, respectively. The Col-PPy-Qur composite observed electrical conductivity at 0.0653 s/cm due to the conductive Polypyrrole polymer present in the composite. The Col-PPy-Qur composite exhibits a mechanical strength of 0.1281 mPa, similar to the native human spinal cord's mechanical strength. In order to explore the regeneration potential, the viability of the composite has been tested with human astrocyte cells (HACs). The Tuj1 and GFAF marker expression was quantized by RT-PCR analysis. Increased Tuj1 and decreased GFAF expression by the Col-PPy-Qur composite indicated the potential differentiation ability of the HACs into neuron cells. The results indicated that the Col-PPy-Qur composite could have good regeneration and differentiation ability, better biocompatibility, and suitable mechanical and conductivity properties. It can act as an excellent strategy for spinal cord regeneration in the nearer future.

Electrophoretic Deposition and Characterization of Er-Doped Bi2O3 Cathode Barrier Coatings on Non-Conductive Ce0.8Sm0.2O1.9 Electrolyte Substrates

In this study, the formation of thin-film barrier coatings based on a highly conductive Bi1.60Er0.4O3 (EDB) solid electrolyte on supporting Ce0.8Sm0.2O1.9 (SDC) electrolyte substrates was implemented for the first time using electrophoretic deposition (EPD). The electrokinetic properties of EDB-based suspensions in a non-aqueous dispersion medium of isopropanol modified with small additions of polyethyleneimine (PEI, 0.26 g/L) and acetylacetone (0.15 g/L), as well as in a mixed isopropanol/acetylacetone (70/30 vol.%) medium, were studied. The dependences of the thickness of the EDB coatings on voltage and deposition time were obtained using deposition on a model Ni foil electrode. Preliminary synthesis of a conductive polypyrrole (PPy) polymer film was used to create surface conductivity on non-conductive SDC substrates. The efficiency of using a modified dispersion medium based on isopropanol to obtain a continuous EDB coating 12 μm thick, sintered at a temperature of 850 °C for 5 h, is shown. The microstructure and morphology of the surface of the EDB coating were studied. A Pt/SDC/EDB/Pt cell was used to characterize the coating’s conductivity. The EPD method is shown to be promising for the formation of barrier coatings based on doped bismuth oxide. The developed method can be used for creating cathode barrier layers in SOFC technology.

Inductive Coupling of Bipolar Signals with a Conjugate Coil Pair for an Analog Passive ECG Sensor Using a PPy-Coated pvCNT Dry Electrodes.

The wireless capture of analog differential signals from fully passive (battery-less) sensors is technically challenging but it can allow for the seamless capture of differential biosignals such as an electrocardiogram (ECG). This paper presents a novel design for the wireless capture of analog differential signals using a novel conjugate coil pair for a wireless resistive analog passive (WRAP) ECG sensor. Furthermore, we integrate this sensor with a new type of dry electrode, namely conductive polymer polypyrrole (PPy)-coated patterned vertical carbon nanotube (pvCNT) electrodes. The proposed circuit uses dual-gate depletion-mode MOSFETs to convert the differential biopotential signals to correlated drain-source resistance changes and the conjugate coil wirelessly transmits the differences of the two input signals. The circuit rejects (17.24 dB) common mode signals and passing only differential signals. We have integrated this novel design with our previously reported PPy-coated pvCNT dry ECG electrodes, fabricated on a stainless steel substrate with a diameter of 10 mm, which provided a zero-power (battery-less) ECG capture system for long duration monitoring. The scanner transmits an RF carrier signal at 8.37 MHz. The proposed ECG WRAP sensor uses only two complementary biopotential amplifier circuits, each of which has a single-depletion MOSFET. The amplitude-modulated RF signal is envelope-detected, filtered, amplified, and transmitted to a computer for signal processing. ECG signals are collected using this WRAP sensor and compared with a commercial counterpart. Due to the battery-less nature of the ECG WRAP sensor, it has the potential to be a body-worn electronic circuit patch with dry pvCNT electrodes that stably operate for a long period of time.

In situ polymerization of polypyrrole in oil body for efficient solar-driven freshwater collection

Solar-driven interfacial water evaporation can be exploited for freshwater generation with clean and pollution-free characteristics. The transport of water molecules from bulk water to the surface of the absorber is a key factor for efficient water evaporation. Herein, an oil body (OB), a spherical organelle extracted from safflower seeds, was used as supporting materials due to its low density and hydrophilic surface. After in situ polymerization of polypyrrole (PPy) in the interior of OB, an OB-PPy absorber with excellent photothermal performance and water transporting ability was obtained. When adding OB-PPy into sewage or seawater, it shows higher water evaporation rate and freshwater collection capabilities than PPy alone. The highest evaporation rate (2.11 kg m-2 h−1) and evaporation efficiency (92.02 %) can be obtained in OB-PPy containing rainwater. The freshwater collection rate can reach 1.38 kg m-2 h−1 when using a homemade freshwater collection device. Moreover, OB-PPy exhibits long term stability and reusability. Interestingly, we have found that OB-PPy lyophilized powder could absorb atmospheric water and produce freshwater from humid air. Therefore, OB-PPy holds great potential for solving the problem of freshwater resource shortage.

Smart fire-safety cotton fabric with fire-warning capability via dual working mechanisms

Increasing demand for fire safety has aroused the enthusiasm of researchers for exploring early-stage fire-warning materials. Herein, an early-stage fire-warning cotton fabric (denoted as CF-CP-FR) was designed with a two-layered structure: conducting polymer layer and flame-retardant layer, through in-situ chemical oxidation polymerization of polypyrrole (PPy) and dip coating of the compound of montmorillonite and ammonium polyphosphate (MMT@APP), respectively. Based on the thermoelectric effect of the PPy, CF-CP-FR was endowed with accurate temperature sensing capability below 100 °C. When encountering fire, CF-CP-FR showed excellent fire-warning response as fast as 1.0 s and displayed repeatable fire-warning capability under the protection of the MMT@APP. Via the mechanism of thermo-induced resistance change, the coated cotton fabric could also trigger the fire warning circuit at ca. 2.0 s. Meanwhile, the flame retardancy and thermal stability of CF-CP-FR were significantly enhanced, owing to the synergetic effect of MMT and APP. This work is promising in fabricating multifunctional clothing with efficient fire safety and smart fire-warning capability.