Polymer Polypyrrole Research Articles

Flexible supercapacitors of biomass-based activated carbon-polypyrrole on eggshell membranes

The quest to develop flexible membrane-like supercapacitors to be applied in advanced electronic devices with a flexible structure is important for the modern world. In this study, we developed biomass-based supercapacitors by depositing activated carbon on an eggshell membrane and subsequently coating these with polypyrrole in a two-step procedure. The competition between the electrical double layer capacitance (EDLC) from activated carbon and the pseudocapacitance (PC) for the hybrid device is controlled by varying the amount of polypyrrole (PC component) in a time-dependent polymerization process. An areal capacitance of 172.5 mF cm−2, a corresponding energy density of 4.73 W h kg−1, and power density of 320.8 W kg−1, with a 60% retention even after 1000 cycles were obtained for samples prepared with the polymerization of polypyrrole on the activated carbon (incorporation of an active layer of 3.18 mg cm−2).

Investigation of the effect of in-situ grown PPy on low frequency dielectric properties and other properties of PVA-PVP blend film

Present study is carried out to understand the effect of conducting polymer, polypyrrole (PPy) on structural, morphological, thermal and dielectric properties of bio-compatible polymer blend film of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP). The growth of PPy in the matrix of PVA–PVP was analyzed using XRD, FT-IR and SEM studies. The shifting in positions and broadening of XRD diffraction peaks of PVA–PVP-PPy from that of PVA–PVP indicates the structural modification and reduction in the crystallinity of the PVA–PVP due to incorporation of PPy. The SEM studies suggest scattered growth of PPy in PVA–PVP matrix at lower concentration of pyrrole monomer. As the monomer concentration is increased, the uniform and interconnected growth of PPy was observed in SEM micrographs. The TGA thermograms show faster thermal degradation of PVA–PVP- PPy films at lower temperature as compared to PVA–PVP films. The blend films of PVA–PVP- PPy exhibited enhanced values of dielectric constant and ac conductivity as compared to the virgin blend film which are observed to increase with increasing concentration of PPy. The high dielectric constant with high ac conductivity exhibited by PVA–PVP-PPy film suggests its possible application as flexible dielectric material for the development of biosensors, energy storage devices in field of green organic electronics.

Phosphate ion sensor fabrication based on conductive polymer polypyrrole film coatings in doped phosphate using thick film technology

This study describes the development of chemical sensors to detect polypyrrole (PPy) based phosphate sensors in doped di-ammonium hydrogen phosphate (DAP) with thick film technology (TFT). Manufacturing screen-printed carbon electrode (SPCE) with thick film uses alumina substrate provided a more portable, miniature, inexpensive, and reduced use of samples and reagents. Polymer polypyrrole and di-ammonium hydrogen phosphate as sensitive membranes are electrodeposition on carbon electrodes. Characterization has been conducted to see the electrode morphology in scanning electron microscopy (SEM) test, which showed that sensitive material particles were distributed evenly on the surface of the sample and spherical. The energy dispersive spectroscopy (EDS) experiment results showed the atomic composition respectively carbon 86.95 %, nitrogen 6.94 %, oxygen 5.9 %, and phosphate 0.21 %, which were exposed to the electrode. The performance test of electrodes with a phosphate standard solution has proceeded at a concentration between 5 to 100 mg/l, which is measured using the galvanostatic method. The voltage range was from 0.252 to 0.957 V with R2 at approximately 90.265 %. The results of sensor performance were concluded that the electrode was able to detect phosphate ions.

A Rapid Analytical Approach for Monitoring Pharmaceuticals in Hospital Wastewater—A DPX-Based Procedure with Environmentally-Friendly Extraction Phase Coupled to High Performance Liquid Chromatography–Diode Array/Fluorescence Detectors

In this study, a novel analytical methodology based on disposable pipette extraction (DPX) was developed using an alternative extraction phase for the extraction/determination of six pharmaceutical compounds, including carbamazepine, diclofenac, naproxen, fluoxetine, losartan and 17α-ethinylestradiol, in samples of hospital wastewater by high-performance liquid chromatography coupled to diode array and fluorescence detectors. The performance of three extraction phases was examined, including 3-n-propyl (3-methylpyridinium) silsesquioxane chloride (Si3Py+Cl−), the conductive polymer polypyrrole (PPy), and polypyrrole modified with cetyltrimethylammonium bromide (PPy.CTAB). The optimization of the experimental parameters was performed through univariate and multivariate approaches. The optimized condition was obtained with the use of 20 mg of Si3Py+Cl− as extraction phase; six extraction cycles with 700 μL of sample in each cycle and 15 s of extraction time; three desorption cycles with 100 μL of ACN (same aliquot) and 15 s of desorption time; and sample pH adjusted at 3.5 and addition of 15% (w/v) of NaCl in the sample. The methodology proposed exhibited environmentally-friendly aspects with a significantly reduced volume of organic solvent (only 100 µL) and a small amount of extraction phase (20 mg). In addition, the extraction phase employed exhibits a simple synthetic procedure, low cost, and high stability in organic solvent. Moreover, the method developed exhibits high throughput (extraction time of 6.5 min per sample), and robustness. The analytical figures of merit were obtained using hospital wastewater, and the values were very satisfactory. The correlation coefficients were higher than 0.9710. LODs and LOQs ranged from 0.030 µg L−1 to 1.510 µg L−1 and 0.10 µg L−1 to 5.00 µg L−1, respectively. Relative recoveries varied from 80 to 127%, and intra-day (n = 3) and inter-day (n = 9) precision was lower than 19%.

Development of a Novel Sensor Based on Polypyrrole Doped with Potassium Hexacyanoferrate (II) for Detection of L-Tryptophan in Pharmaceutics

This study describes the development of a new sensor with applicability in the determination and quantification of yjr essential amino acid (AA) L-tryptophan (L-TRP) from pharmaceutical products. The proposed sensor is based on a carbon screen-printed electrode (SPCE) modified with the conductor polymer polypyrrole (PPy) doped with potassium hexacyanoferrate (II) (FeCN). For the modification of the SPCE with the PPy doped with FeCN, the chronoamperometry (CA) method was used. For the study of the electrochemical behavior and the sensitive properties of the sensor when detecting L-TRP, the cyclic voltammetry (CV) method was used. This developed electrode has shown a high sensibility, a low detection limit (LOD) of up to 1.05 × 10−7 M, a quantification limit (LOQ) equal to 3.51 × 10−7 M and a wide linearity range between 3.3 × 10−7 M and 1.06 × 10−5 M. The analytical performances of the device were studied for the detection of AA L-TRP from pharmaceutical products, obtaining excellent results. The validation of the electroanalytical method was performed by using the standard method with good results.

Conductive Polymer Intercalation Tunes Charge Transfer and Sorption-Desorption Properties of LDH Enabling Efficient Alkaline Water Oxidation.

Controlling and tuning surface properties of a catalyst have always been a prime challenge for efficient hydrogen production via water splitting. Here, we report a facile method for tuning both charger transfer and sorption-desorption properties of NiFe layered double hydroxide (LDH) by intercalating a conductive polymer of polypyrrole (ppy) via an interlayer confined polymerization synthesis (ICPS) process. Ex situ characterizations and in situ electrochemical quartz-crystal microbalance with dissipation (EQCM-D) tracking experiments showed that the intercalated ppy not only improved the charge transfer property of the resulting hybrid catalyst LDH-ppy but also made it more flexible and adaptive for quick and reversible sorption-desorption of reactants and intermediates during the oxygen evolution reaction (OER) process. Consequently, the as-prepared LDH-ppy exhibited a doubled catalytic current density over the bare LDH, as visualized by in situ scanning electrochemical microscopy (SECM) at the subnanometer scale. This work sheds light on orchestrating the charge and sorbate transfer abilities of catalysts for efficient water splitting by smartly combining inorganic and organic layers.

Polypyrrole decorated ZnTi hydrotalcite with enhanced adsorption and Cr(VI) photoreduction activity under visible-light

A conjugated polymer polypyrrole (PPy) was used to decorate the ZnTi hydrotalcite (ZnTi-LDH) for constructing an organic–inorganic PPy/ZnTi-LDH composite by a facile in-situ oxidation polymerization. It was found that the as-prepared composite displayed a superior photocatalytic performance and excellent stability under visible light irradiation, which Cr(VI) reduction efficiency (99.72% for 35 min) was around 53 and 12 times higher than those of the pristine ZnTi-LDH and pure PPy, respectively, and still maintained 95.10% even after 5th cycles. The dramatically enhanced photocatalytic performances were attributed to the beneficial combination of the ZnTi-LDH stratified structure and conductive PPy, which effectively facilitated charge transfer, restrained recombination, and increased visible-light absorption. Particularly, PPy as a remarkable conductive polymer, played a crucial role in the Cr(VI) reduction, which not only was a light acceptor to produce photo-generated charge carriers but also provided a good electron transport path to accelerate the separation and migration of electron-hole pairs to improve the photoreduction performances. Finally, possible photocatalytic reaction mechanism of the PPy/ZnTi-LDH was also proposed.

Tailoring gold-conducting polymer nanocomposites for sensors applications: Proof of concept for As(III) sensing in aqueous media

Nanocomposites of gold nanoparticles (AuNPs) and conducting polymers, polypyrrole (PPy) and polyaniline (PANI), were prepared by simple oxidative polymerization of the corresponding monomer (pyrrole and aniline, respectively) by tetrachloroauric acid. Au nanospheres and nanorods were formed in the case of Au@PPy and Au@PANI, respectively. Detection of As(III) using Au@polymer was investigated where both nanocomposites showed similar activity for As electrooxidation in acidic media. The activity of Au@PPy was notably improved upon the addition of a small amount of conducting carbon, giving higher current densities compared to the commercial Au electrode. Further optimization of the operational conditions including electrolyte composition, deposition time and potential, was carried out to reach the limit of quantification as low as 2 ppb. Au@PPy nanocomposite proved to be suitable for sensing of As(III) in the presence of other ions, such as Cu(II). Furthermore, it proved to be suitable for As(III) sensing in real samples.

Ti3C2-MXene composite films functionalized with polypyrrole and ionic liquid-based microemulsion particles for supercapacitor applications

Stemming from its unique structure and properties, Ti3C2-MXenes have stood out from the crowd of electrode materials due to effectively ameliorating imperfections of common ones for excellent energy storage. However, a major stumbling block in the further development of MXene-based supercapacitors is the inherent low capacities caused by severe restacking of nanosheets. Herein, we develop a simple, effective and innovative strategy, namely, introducing both polymerized polypyrrole (PPy) particles and ionic liquid (ILs)-based microemulsion particles as “dual spacers”, to fabricate functionalized Ti3C2-MXene composite films for high-performance and wide-temperature application in supercapacitors. The PPy particles acting as one “spacer” circumvent restacking issues of MXene nanosheets, while contribute to desirable capacitance of the hybrid material. ILs-based microemulsions spontaneously adsorbing onto PPy-Ti3C2Tx nanosheets are conceived to be one more liquid “spacer” for fast ion diffusion kinetics and absent electrolyte imbibition steps, which is rarely reported in previous research for MXene-based electrode materials. These features endow the composite films with excellent specific capacitance, rate capability and cycling stability between 4 °C and 50 °C. At room temperature, the symmetric supercapacitor device based on the composite films delivers a maximum gravimetric energy density of 31.2 Wh kg−1 (at 1030.4 W kg−1) and reserves 91% of the initial specific capacitance with a coulombic efficiency of 91% after 2000 cycles. All these impressive results substantiate that the composite films prepared by ingenious structure design showcase huge potentials in advanced MXene-based supercapacitors using various ionic liquid electrolytes.

Multifunctional Cellulose Nanopaper with Superior Water-Resistant, Conductive, and Antibacterial Properties Functionalized with Chitosan and Polypyrrole.

Cellulose nanopaper (CNP) has been considered as a promising material with great application potential in diverse fields. However, the hydrophilic nature of CNP significantly limits its practical application. In order to improve its water resistance, we demonstrate a facile approach to functionalize CNP by impregnating it with chitosan (CS), followed by in situ polymerization of polypyrrole (PPy). The results indicate that the obtained CNP/CS/PPy shows excellent water resistance with the wet tensile strength of up to 80 MPa, which is more than 10 times higher than that of the pure CNP. Intriguingly, new features (e.g., electrical conductivity, antibacterial activity, and so forth) are achieved at the same time. The functionalized CNP/CS/PPy shows a high conductivity of 6.5 S cm-1, which can be used for electromagnetic interference shielding applications with a high shielding performance of around 18 dB. In addition, the CNP/CS/PPy exhibits good antibacterial activity toward Staphylococcus aureus and Escherichia coli, with the bacterial reductions of 99.28 and 95.59%, respectively. Thus, this work provides a simple and versatile approach to functionalize CNP for achieving multifunctional properties.

Highly stretchable self-sensing actuator based on conductive photothermally-responsive hydrogel

Soft robots built with active soft materials have been increasingly attractive. Despite tremendous efforts in soft sensors and actuators, it remains extremely challenging to construct intelligent soft materials that simultaneously actuate and sense their own motions, resembling living organisms’ neuromuscular behaviors. This work presents a soft robotic strategy that couples actuation and strain-sensing into a single homogeneous material, composed of an interpenetrating double-network of a nanostructured thermo-responsive hydrogel poly(N-isopropylacrylamide) (PNIPAAm) and a light-absorbing, electrically conductive polymer polypyrrole (PPy). This design grants the material both photo/thermal-responsiveness and piezoresistive-responsiveness, enabling remotely-triggered actuation and local strain-sensing. This self-sensing actuating soft material demonstrated ultra-high stretchability (210%) and large volume shrinkage (70%) rapidly upon irradiation or heating (13%/°C, 6-time faster than conventional PNIPAAm). The significant deswelling of the hydrogel network induces densification of percolation in the PPy network, leading to a drastic conductivity change upon locomotion with a gauge factor of 1.0. The material demonstrated a variety of precise and remotely-driven photo-responsive locomotion such as signal-tracking, bending, weightlifting, object grasping and transporting, while simultaneously monitoring these motions itself via real-time resistance change. The multifunctional sensory actuatable materials may lead to the next-generation soft robots of higher levels of autonomy and complexity with self-diagnostic feedback control.

Reviving of silicon waste with N-doped carbon core-shell structure prepared by vapor deposition polymerization of polypyrrole applied in lithium-ion battery

Lithium-ion battery is widely attracted in energy storage system owing to the high energy density and low cost. Silicon (Si) is regarded as the high capacity anode materials for replacing graphite to enhance the battery's energy density. However, the rapid fading during the charging and discharging process causes the battery system's poor retention. In this study, the waste Si from the photovoltaic industry is reused as anode materials. Furthermore, polypyrrole's vapor deposition polymerization is considered the N-doped carbon source, enhancing the electrochemical performance. The vapor deposition method offers a homogeneous coating solution, improving the material conductivity, and reducing the charge transfer resistance. In the electrochemical test, the Si/N-doped carbon sample demonstrates 3353mAh/g capacity at the current density of 0.5A/g in the first cycle. After 100 cycles, the sample reveals 787mAh/g, which is much higher than that without N-doped carbon coating (about 620mAh/g higher than waste-Si). Moreover, it also displays high capability in high current rate charging-discharging. Overall, N-doped carbon coating from vapor deposition polymerization is a facile method to decrease the Li-ion transport energy barrier and improve the electrochemical performance of waste Si for next-generation lithium-ion batteries.

Preliminary study on the performance of a redox capacitor with the use of ionic liquid-based gel polymer electrolyte and polypyrrole electrodes

Redox capacitor, which is one type of supercapacitor, has been attracted tremendously as it shows a satisfactory specific capacitance, good cycle ability, and good stability. The present study reveals a redox capacitor fabricated with an ionic liquid (IL)-based gel polymer electrolyte (GPE). Electrodes of the redox capacitor were fabricated with the conducting polymer, polypyrrole (PPy). The composition of the GPE was polyvinylidenefluoride–co-hexafluoropropylene (PVdF–co-HFP): 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (1E3MITF): ZnTF. Characterization of redox capacitor was done by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) tests. The relaxation time constant (τ0) of the redox capacitor is about 31.57 s implying somewhat fast redox reactions. Initial single electrode specific capacitance (CSC) was 150.2 Fg−1, and at the 500th cycle, it was 40.03 Fg−1. The decrease of the CSC may be due to the formation of the passivation layer at the GPE/electrode interface, resulting in degradation upon cycling. The GCD test resulted 48.4 Fg−1 of initial single-electrode specific discharge capacitance (Csd) value. Upon 1000 cycles, it was reached 22.3 Fg−1. The decrease of Csd may be due to the degradation of the electrode and the IL-based GPE upon prolonged cycling.

Utilisation of pyrochlore-typeoxideas catalyst in bioanode of coffee mac microbial fuel cell: Boost of electric voltage and reduction of wastes

ABSTRACT This study is a contribution to development of material based on transition metal oxides with application in electrochemical devices. A pyrochlore-like solid solution with general chemical formula Bi1.2Ce0.3Sb1.5CuO7 was synthesised. The pyrochlore structure was determined by X-ray powder diffraction. The pressed pyrochlore powder sample was analysed by scanning electron microscopy to show effect of substitution fraction of cerium and to determine its grain size and morphology. Energy dispersive of X-rays was performed to confirm effective substitution of bismuth for cerium. The EDX analysis was supported by X-ray photoelectron spectroscopy which also gave information on respective oxidation states of cations. Several modes of vibration due to metal-oxygen bonds of pyrochlore-like material were studied by Fourier-transform infrared spectroscopy. The results suggested that this compound contained major component of pyrochlore and minor component of CeO2. The dielectric measurements carried out at frequency 1 MHz in temperature range –40°C–90°C proved that pyrochlore compound possessed dielectric constants ranging between 12 and 28. Furthermore, owing to its high electrical conductivity, synthesised material has been utilised as bioanode in a microbial fuel cell. This bio-electrochemical device converted organic wastes into electricity using microorganisms as biocatalysts. It displayed greater electron transfer from electroactive biofilm towards the bioanode by improving its electrical energy output. The presence of pyrochlore in electrode allowed a power density of 25 mW/m2. It was almost the same as that obtained with a graphite carbon modified by the conducting polymer polypyrrole. The MFC with pyrochlore solid oxide was advantageously more stable having longer lifetime and indicating its suitability to substitute the polypyrrole at the bioanode. Besides, the colour of the coffee mac leachate in the anolyte (anode compartment) became less dark, which means that the maximum chemical oxygen demand (COD) was removed and converted into electric energy.

Soft conducting polymer polypyrrole actuation based on poly(N-isopropylacrylamide) hydrogels

The conducting polymer, polypyrrole (PPy), has been widely studied as electrochemical actuators due to their electrochemical stability, fast actuation and high strains. However, conducting polymers films are rigid and brittle, which limit their applications. Conducting polymer hydrogel composites take advantage of hydrogels’ elastic properties and extend their use to biological applications, implants and flexible sensor applications. We systematically investigated the out-of-plane actuation of poly(N-isopropylacrylamide) (pNIPAM) hydrogel by utilising the redox properties of a PPy film. We assess the PPy film growth with different sized dopants and find that PPy-dodecylbenzene sulfonate (DBS) films exhibited the largest strain (∼20 %) with a cation-driven actuation. We show that the Young's Modulus of the composite hydrogel was ∼10 kPa, which remained constant regardless of the redox state of PPy. Furthermore, we show that the PPy-DBS film grown in the pNIPAM hydrogel exhibits more than x2 the actuation of the PPy-DBS film alone by electrochemical switching of the redox state. This system has potential applications for soft actuators, controlling ion flux, drug delivery or applying electrical stimuli for cell culture studies.

Intercalation of soft PPy polymeric nanoparticles in graphene oxide membrane for enhancing nanofiltration performances

• PPy particles make GOM with dye adsorption function for sub-nano dyes removement. • Intercalation of PPy improves the GOM’s stability extremely. • PPy nanoparticles modified GOM resulting in 14 times faster water flux. • PPy inhibits the swelling feature of GOM and exhibits improved separation ability. Graphene oxide-based membrane (GOM) has been massively studied in the dye/water separation field, predominately relying on their 1 nm-sized interlayer distance spacing (D-spacing). However, the inefficient removal of sub-nanosized dye molecules and swelling-induced weak long-term stability are currently two key challenges faced by GOM. In this work, we intercalate the soft polymeric polypyrrole (PPy) nanoparticles into GOM to address such gaps. The strong dye adsorption ability of PPy results in the increase of the sub-nanosized MB molecule rejection rate from 60% for GOM to 97% for GO-PPy membrane (GPM) after the initial filtration treatment. Simultaneously, the nanochannels of GPM are partially expanded, leading to an approximately a ~14 times water permeability (21.14 L m -2 h −1 bar −1 ) improvement over GOM (1.56 L m -2 h −1 bar −1 ). More importantly, the strong hydrogen-bond, electrostatic, and π-π interactions between GO and PPy improve the membrane mechanical stability and further reduce the D-spacing, while the enhanced separation ability of nano-sized dye molecules is also exhibited evidenced by the > 99% rejection rates of CV, EBT, CR, and TB. We consider that our strategy could promote the design and development of the high-performance GOM for nanofiltration applications.

Effect of solvent exchange on the properties of carbon xerogel and carbon xerogel/polypyrrole composites for supercapacitors

Carbon xerogels (CXs) with three-dimensional (3D) structure, unusual surface, physical, electrical and mechanical properties and their electrically conductive polymer polypyrrole (PPy) composites were synthesized as electrode materials for supercapacitors. The effect of different resorcinol/formaldehyde (R/C) ratios, whether solvent exchange with or without acetone and polypyrrole addition on the physicochemical (FTIR, XRD, BET, SEM and TGA) and electrochemical properties (CV, 1000 cycles) of the synthesized materials were investigated. It was observed that the R/C ratio and the solvent exchange process prior to drying affect the specific surface areas and the pore size distributions, thereby positively affecting the specific capacitance. PPy film thickness was observed to be effective in the specific capacitance of the electrode in PPy composite synthesis. Among the synthesized materials, the highest specific capacitance values belong to polypyrrole/carbon xerogel composites. As a result of the analysis and calculations, it was found that the highest specific capacitance belongs to CX2/PPy composite with 599 Fg−1 at 5 mVs−1. CX2/PPy composite has been found to have a capacitance retention rate of 80.30% at the end of 1000 cycles.

Encapsulating manganese oxide nanoparticles within conducting polypyrrole via in situ redox reaction and oxidative polymerization for long-life lithium-ion batteries

Manganese oxides (MnOx) have been extensively investigated due to their extremely high theoretical capacities for application as conversion anodes in lithium-ion batteries. However, fully performing their theoretical performance still faces poor electric conductivity and serious volume change upon lithium insertion/extraction. Herein, we demonstrate encapsulating manganese oxide nanoparticles within a conducting polymer polypyrrole (PPy) shell as a facile strategy to overcome such flaws through in situ redox reaction and oxidative polymerization process. Such an in situ method combines the redox reaction between potassium permanganate and tetrahydrofuran to form MnOx nanoparticles and the subsequent oxidative polymerization of pyrrole to form a conductive polypyrrole coating shell by the oxidant KMnO4 into one step. For the as-fabricated products (MnOx@PPy), this tenderly introduced conductive PPy shell highly favors the fast electron transfer and preserves the electrode structure integrity upon repeated cycling. As the anode for LIBs, MnOx@PPy exhibits superior lithium storage performance with a high reversible capacity (1538 mAh·g−1), long-life cyclability (747 mAh·g−1 after 1000 cycles at 1.0C) and durable ratability (574 mAh·g−1 at 2.0C). This work demonstrates that the convenient in situ strategy to form conductive polymer coating shell is effective to improve the performance of conversion anodes and can be extended to other materials for energy storage applications.

Multifunctional and superhydrophobic cellulose composite paper for electromagnetic shielding, hydraulic triboelectric nanogenerator and Joule heating applications

• Multifunctional and superhydrophobic cellulose composite paper (CCP) is fabricated. • CCP shows a high EMI shielding effectiveness and electrical conductivity. • The superhydrophobic surface is used as the hydraulic triboelectric nanogenerator. • Surface temperature of CCP can reach 140 °C with a applied voltage of 6 V. Cellulose-based materials have attracted tremendous interest recently due to their fascinating merits of renewability, biodegradability, and low cost, holding great promise in electromagnetic protection, clean energy harvesting, and thermal management. However, the simple and effective integration of multiple functions into single cellulose material remains a challenge. Herein, we report the fabrication of a multifunctional and superhydrophobic cellulose composite paper (CCP) via coated MXene modified by in-situ polymerized polypyrrole and PDMS/candle soot on the opposite surface of the paper. CCP exhibits high-performance electromagnetic interference shielding effectiveness (~40 dB) while maintaining high electrical conductivity (1467 S/m). Moreover, the superhydrophobic surface of CCP can be used as the hydraulic triboelectric nanogenerator (H-TENG) to harvest water energy due to the liquid–solid contact triboelectrification and electrostatic induction. The hydraulic triboelectric energy can be captured and released when water droplets drop from a height of 2 cm and roll at a tilt angle of 20°, the output current can reach a peak of 0.8 nA. Furthermore, the surface saturation temperature of CCP can reach 140 °C with a low applied voltage of 6 V enabled by the Joule effect. Thus, CCP holds great potentials in applications of integrated smart electronics, clean energy harvesting, and thermal management.

Antimicrobial properties of multifunctional polypyrrole-cobalt oxide-silver nanocomposite against pathogenic bacteria and parasite.

Conducting polymer based nanocomposites are known to be effective against pathogens. Herein,we report the antimicrobial properties of multifunctional polypyrrole-cobalt oxide-silver nanocomposite (PPy-Co3O4-AgNPs) for the first time. Antibacterial activities were tested against multi-drug-resistant Gram-negative Escherichia coli (E. coli) and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) bacteria, while antiamoebic effects were assessed against opportunistic protist Acanthamoeba castellanii (A. castellanii). The ternary nanocomposite containing conducting polymer polypyrrole, cobalt oxide, and silver nanoparticles showed potent antimicrobial effects against these pathogens. The antibacterial assay showed that PPy-Co3O4-AgNPs exhibited significant bactericidal activity against neuropathogenic E. coli K1 at only 8 μg/mL as compared to individual components of the nanocomposite, whereas a 70 % inhibition of A. castellanii viability was observed at 50 μg/mL. Moreover, PPy-Co3O4-AgNPs were found to have minimal cytotoxicity against human keratinocytes HaCaT cells in vitro even at higher concentration (50 μg/mL), and also reduced the microbes-mediated cytopathogenicity against host cells. These results demonstrate that PPy-Co3O4-AgNPs hold promise in the development of novel antimicrobial nanomaterials for biomedical applications. •Synthesis of polypyrrole-cobalt oxide-silver (PPy-Co3O4-AgNPs) nanocomposite. •Antimicrobial activity of nanocomposite. •PPy-Co3O4-AgNPs hold promise for biomedical applications.