Ammonia is toxic, colorless, and harmful to human health. It is important to detect ammonia effectively by gas sensors. In this paper, the mechanism of ammonia sensing on polypyrroles (PPy) films at room temperature h...Ammonia is toxic, colorless, and harmful to human health. It is important to detect ammonia effectively by gas sensors. In this paper, the mechanism of ammonia sensing on polypyrroles (PPy) films at room temperature has been investigated using a real-time, in-situ Fourier-transform infrared (FT-IR) spectroscopy. The introduction of ammonia results in a structural transformation of PPy films, which is confirmed by FT-IR spectrums. The structure and morphology of the products after the reaction between ammonia and PPy were investigated in detail by FT-IR spectrum and scanning electron microscope (SEM). It was found that the morphology of PPy films was changed to some degree after the reaction. Our results demonstrate that FT-IR spectroscopy is an extremely suitable technique for the characterization of the specific reaction between PPy and ammonia, since it allows monitoring the reaction at room temperature in real time. After the reaction between PPy and ammonia, the concentration of the carrier increases, and the resistance of PPy films decreases, indicating the sensitivity of detection of ammonia.展开更多
Robust, ultra-flexible, and multifunctional MXene-basedelectromagnetic interference (EMI) shielding nanocomposite filmsexhibit enormous potential for applications in artificial intelligence,wireless telecommunication,...Robust, ultra-flexible, and multifunctional MXene-basedelectromagnetic interference (EMI) shielding nanocomposite filmsexhibit enormous potential for applications in artificial intelligence,wireless telecommunication, and portable/wearable electronic equipment.In this work, a nacre-inspired multifunctional heterocyclic aramid(HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite paper withlarge-scale, high strength, super toughness, and excellent tolerance tocomplex conditions is fabricated through the strategy of HA/MXenehydrogel template-assisted in-situ assembly of PPy. Benefiting from the"brick-and-mortar" layered structure and the strong hydrogen-bondinginteractions among MXene, HA, and PPy, the paper exhibits remarkable mechanical performances, including high tensile strength (309.7 MPa),outstanding toughness (57.6 MJ m−3), exceptional foldability, and structural stability against ultrasonication. By using the template effect ofHA/MXene to guide the assembly of conductive polymers, the synthesized paper obtains excellent electronic conductivity. More importantly,the highly continuous conductive path enables the nanocomposite paper to achieve a splendid EMI shielding effectiveness (EMI SE) of 54.1 dBat an ultra-thin thickness (25.4 μm) and a high specific EMI SE of 17,204.7 dB cm2g−1. In addition, the papers also have excellent applicationsin electromagnetic protection, electro-/photothermal de-icing, thermal therapy, and fire safety. These findings broaden the ideas for developinghigh-performance and multifunctional MXene-based films with enormous application potential in EMI shielding and thermal management.展开更多
As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal...As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal conversion ability have received extensive attention.Meeting the aforesaid requirements simultaneously remains a huge challenge.In this research,the melamine foam(MF)/polypyrrole(PPy)nanowire arrays(MF@PPy)were fabricated via one-step electrochemical polymerization.The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays.Due to the upwardly grown PPy nanowire arrays,the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00°and outstanding stability under various harsh environments.Meanwhile,the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays.Furthermore,taking advantage of the high conductivity(128.2 S m^(-1)),the MF@PPy foam exhibited rapid Joule heating under 3 V,resulting in dynamic infrared stealth and thermal camouflage effects.More importantly,the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm^(2)g^(-1).Strong EMI shielding was put down to the hierarchically porous PPy structure,which offered outstanding impedance matching,conduction loss,and multiple attenuations.This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays,showing great applications in both military and civilian fields.展开更多
To prepare a conductive polymer actuator with decent performance,a self-built experimental platform for the preparation of polypyrrole film is employed.One of the essential goals is to examine the mechanical character...To prepare a conductive polymer actuator with decent performance,a self-built experimental platform for the preparation of polypyrrole film is employed.One of the essential goals is to examine the mechanical characteristics of the actuator in the presence of various combinations of process parameters,combined with the orthogonal test method of"four factors and three levels".The bending and sensing characteristics of actuators of various sizes are methodically examined using a self-made bending polypyrrole actuator.The functional relationship between the bending displacement and the output voltage signal is established by studying the characteristics of the actuator sensor subjected to various degrees of bending.The experimental results reveal that the bending displacement of the actuator tip almost exhibits a linear variation as a function of length and width.When the voltage reaches 0.8 V,the bending speed of the actuator tends to be stable.Finally,the mechanical properties of the self-assembled polypyrrole actuator are verified by the design and fabrication of the microgripper.展开更多
Surface modification is found to be an effective way to control the initial degradation of Mg based biomedical alloys.The present study focuses on the modulation of in vitro and in vivo degradation behavior of Mg-Ce a...Surface modification is found to be an effective way to control the initial degradation of Mg based biomedical alloys.The present study focuses on the modulation of in vitro and in vivo degradation behavior of Mg-Ce alloy through a stearic acid-treated polypyrrole coating,which developed superhydrophobic surface(contact angle∼153°)that drastically enhanced the corrosion resistance(more than 85%efficacy).Cerium addition to Mg alloy results basal texture strengthening and grain refinement,resulting in improved mechanical properties.All the specimens exhibited excellent antibacterial performance against gram-negative E.Coli(DH5α)and gram positive S.aureus bacteria.The oligodynamic effect of polypyrrole coating leads to complete bacterial mitigation.Non-toxic nature of the specimens was studied by MC3T3-E1 cell proliferation and differentiation in indirect cell culture method.Improved corrosion resistance of the coated specimen leads to enhanced cell proliferation and osteogenic differentiation.Hard tissue histology and micro-CT analysis exhibited higher fraction of newly formed callus tissues and highest bone-implant integration across the coated specimen,when implanted in rabbit femur.Efficacy of the material in fracture healing was evaluated by implanting bone plate and screw in a clinically fractured goat tibia.At 3 months,complete fracture healed with no vital organ toxicity was observed for the coated specimen.The present results suggest that Ce addition and polypyrrole coating are effective ways to modulate the corrosion and biocompatibility behavior making it a potential candidate for fracture fixation applications.展开更多
Textiles for health and sporting activity monitoring are on the rise with the advent of smart portable wearables.The intention of this work is to design wireless monitoring wearables,based on widely available textiles...Textiles for health and sporting activity monitoring are on the rise with the advent of smart portable wearables.The intention of this work is to design wireless monitoring wearables,based on widely available textiles and low environmental impact production technologies.Herein we have developed a polymeric ink which is able to functionalize different types of textile fibers(including silver conducting fibers,cotton,and commercial textile)with poly pyrrole.These fibers were weaved together with a thinner silver conducting fiber and carbon fiber to form a touch-sensitive energy harvesting system that would generate an electric output when mechanical pressure is applied to it.Different prototypes were manufactured with loom weaving accessories to simulate real textile cloths.By simple touch,the prototypes produced a maximum voltage of 244 V and a maximum power density of 2.29 W m^(-2).The current generated is then transformed into a digital signal,which is further utilized for human motion or gesture monitorization.The system comprises a wireless block for the Internet of Things(IoT)applicability that will be eventually extended to future remote health and sports monitoring systems.展开更多
Conductive hydrogels derived from natural polymers have attracted increasing attention in wearable electronics due to their inherent biocompatibility and sustainability.However,their poor mechanical strength,limited c...Conductive hydrogels derived from natural polymers have attracted increasing attention in wearable electronics due to their inherent biocompatibility and sustainability.However,their poor mechanical strength,limited conductivity and unsatisfactory environmental adaptability remain significant challenges fo r practical applications.In this study,we report a high-performance gelatin-based conductive hydrogel(GPC)reinforced with polypyrrole-decorated cellulose nanofibers(PPy@CNF)and enhanced by a zwitterionic betaine/(NH_(4))_(2)SO_(4) solution.The PPy@CNF hybrid nanofillers were synthesized via in situ oxidative polymerization,enabling homogeneous dispersion of PPy along the CNF su rface.The incorporation of PPy@CNF significantly improved both mechanical strength and conductivity of the gelatin hydrogel.Meanwhile,the Hofmeister effect induced by(NH_(4))_(2)SO_(4) strengthened the hydrogel network,and the introduction of betaine further enhanced its anti-freezing and moisture-retention properties.The optimized GPC hydrogel exhibited a high tensile strength of 1.02 MPa,conductivity of 1.5 S·m^(-1),and stable performance at temperatures down to-50℃.Furthermore,it was successfully assembled into a wearable strain sensor for real-time human motion monitoring,and as an electrode layer in a flexible triboelectric nanogenerator(TENG),enabling biomechanical energy harvesting and self-powered sensing.This work provides a promising strategy for developing sustainable,multifu nctional hydrogels for next-generation weara ble electronics.展开更多
Reducing the highly toxic Cr(Ⅵ)to safe levels is a critical challenge in water treatment,essential for protecting both ecosystems and human health.In this study,we present a facile in situ polymerization approach to ...Reducing the highly toxic Cr(Ⅵ)to safe levels is a critical challenge in water treatment,essential for protecting both ecosystems and human health.In this study,we present a facile in situ polymerization approach to prepare polypyrrole-coated layered double hydroxide composites(PPy/NiFe LDHs).Compared with other LDHs and polypyrrole-based materials,the synthesized PPy/LDHs exhibit excellent adsorption performance under mildly acidic conditions,achieving a maximum Cr(Ⅵ)adsorption capacity of440.4 mg/g at pH 5.Notably,PPy/LDH effectively reduces Cr(Ⅵ)concentration from 10 mg/L to 0.028 mg/L,well below the maximum permissible level of 0.05 mg/L for drinking water.Additionally,PPy/LDH demonstrates durable stability;at pH 5,nickel and iron ions are not detected after adsorption,and trivalent chromium remains fixed on the material without re-release into the solution following reduction.The adsorption behavior and mechanistic analysis indicate that a combination of adsorption and reduction drives Cr(Ⅵ)removal by PPy/LDHs.This work offers an innovative approach to effectively remove the low concentrations of Cr(Ⅵ)from water,showing significant potential for efficient Cr(Ⅵ)remediation.展开更多
Proton exchange membrane fuel cells(PEMFCs)have gained increasing interests as promising power sources due to their ability to convert hydrogen and oxygen directly into electricity with high efficiency and zero greenh...Proton exchange membrane fuel cells(PEMFCs)have gained increasing interests as promising power sources due to their ability to convert hydrogen and oxygen directly into electricity with high efficiency and zero greenhouse gas emissions.Bipolar plates(BPs)are considered as a critical component of PEMFCs,serving to collect current,separate gases,distribute the flow field,and conduct heat.This paper reviews the technical status and advancements in BP materials,with special focus on strategies for enhancing interfacial contact resistance(ICR)and corrosion resistance through conductive polymer(CP)coatings.First,commonly used BP materials in PEMFCs are summarized.Then,the advantages and limitations of various coatings for metallic BPs are discussed.Finally,recent progress in CP coatings for metallic BPs,aimed at achieving high corrosion resistance and low ICR,is comprehensively reviewed.展开更多
Active sulfur dissolution and shuttle effect of lithium polysulfides(LiPSs)are the main obstacles hindering the practical application of lithium-sulfur batteries(LSBs),which is primarily induced by the direct interact...Active sulfur dissolution and shuttle effect of lithium polysulfides(LiPSs)are the main obstacles hindering the practical application of lithium-sulfur batteries(LSBs),which is primarily induced by the direct interaction between sulfur-loading cathode and liquid electrolyte.The introduction of functional interlayer within the separator and cathode is an effective strategy to stabilize the electrode/electrolyte interface reaction and improve the utilization rate of active sulfur.Herein,conductive composite nanofabrics(CCN)with multifunctional groups are employed as the interlayer of sulfur-loading cathode,in which the PMIA/PAN supporting fibers offer robust mechanical strength and high thermostable performance,and gelatin/polypyrrole functional fibers ensure high electrical conductivity and strong chemical interaction for LiPSs.As demonstrated by the experimental data and material characterizations,the presence of CCN interlayer not only blocks the shuttle behavior of LiPSs,but also strengthens the interface stability of both Li anode and sulfur-loading cathode.Interestingly,the assembled LSBs with CCN interlayer can maintain stable capacity of 686 mAh/g after 200 cycles at 0.5 A/g.This work will provide new ideas for the elaborate design of functional in terlayers/se para tors for LSBs and lithium metal batteries.展开更多
The rational design of composition and microstructure is a proven strategy for developing multifunctional high-performance electromagnetic wave(EMW)absorbers.In this study,a sandwich-structured multilayer nanoplate-li...The rational design of composition and microstructure is a proven strategy for developing multifunctional high-performance electromagnetic wave(EMW)absorbers.In this study,a sandwich-structured multilayer nanoplate-like Bi_(2)Fe_(4)O_(9)@Polypyrrole(BFO@PPy)heterostructure was successfully designed and fabricated using an efficient microwave hydrothermal method and an in situ polymerization process.Specifically,Bi_(2)Fe_(4)O_(9)enhances the chemical activity of ammonium persulfate,which in turn initiates the polymerization of pyrrole monomers,resulting in the formation of BFO@PPy heterostructures.The thickness of the PPy coating layer in the BFO@PPy composite can be precisely controlled at the nanoscale,optimizing electromagnetic parameters,conduction losses and interface polarization loss.The fabricated BFO@PPy composite achieves a minimum reflection loss(RL_(min))of-57.8 dB at a thickness of 2.5 mm and an effective absorption bandwidth(EAB)of 6.96 GHz.Furthermore,the EMW absorption performance and mechanism were systematically validated through theoretical calculations,radar cross-sectional simulations(RCS),and first-principles analysis.Notably,the RCS simulation of a 1:1 scale F-22 Raptor fighter model provides a realistic evaluation of the composite's EMW absorption potential in military applications.The efficient fabrication method and superior electromagnetic absorption performance make BFO@PPy a promising candidate for use in complex electromagnetic environments and military domains.Additionally,the BFO@PPy composite exhibits rapid electrothermal conversion at a low voltage(3V),achieving active infrared camouflage within a controllable temperature range,further highlighting its multifunctional properties.展开更多
In this paper,we present a novel approach to enhancing the visible light photodetection efficiency of reduced graphene oxide(rGO)by incorporating polypyrrole(Ppy)nanoparticles sized between 126 nm and 1025 nm.The rGO ...In this paper,we present a novel approach to enhancing the visible light photodetection efficiency of reduced graphene oxide(rGO)by incorporating polypyrrole(Ppy)nanoparticles sized between 126 nm and 1025 nm.The rGO and Ppy nanoparticles were synthesized via Hummer’s method and chemical polymerization,respectively.Characterization was performed using scanning electron microscope(SEM),transmission electron microscope(TEM),Raman spectroscopy,and optical measurements.The rGO/Ppy photodetector demonstrated a high photoresponsivity of 15 mA/W and a broad spectral response from 405 nm to 805 nm,indicating improved efficiency and versatility.This study high-lights the potential of tailored Ppy nanoparticle sizes in advancing rGO photodetectors for high-performance optoelectronic applications.展开更多
The development of highly efficient catalysts for cathodes remains an important objective of fuel cell research. Here, we report Co3O4 nanoparticles assembled on a polypyrrole/graphene oxide electrocatalyst （C...The development of highly efficient catalysts for cathodes remains an important objective of fuel cell research. Here, we report Co3O4 nanoparticles assembled on a polypyrrole/graphene oxide electrocatalyst （Co3O4/Ppy/GO） as an efficient catalyst for the oxygen reduction reaction （ORR） in alkaline media. The catalyst was prepared via the hydrothermal reaction of Co2＋ ions with Ppy-modified GO. The GO, Ppy/GO, and Co3O4/Ppy/GO were characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The incorporation of Ppy into GO nanosheets resulted in the formation of a nitrogen-modified GO po-rous structure, which acted as an efficient electron-transport network for the ORR. With further anchoring of Co3O4 on Ppy/GO, the as-prepared Co3O4/Ppy/GO exhibited excellent ORR activity and followed a four-electron route mechanism for the ORR in alkaline solution. An onset potential of -0.10 V vs. a saturated calomel electrode and a diffusion limiting current density of 2.30 mA/cm^2 were achieved for the Co3O4/Ppy/GO catalyst heated at 800 ℃; these values are comparable to those for noble-metal-based Pt/C catalysts. Our work demonstrates that Co3O4/Ppy/GO is highly active for the ORR. Notably, the Ppy coupling effects between Co3O4 and GO provide a new route for the preparation of efficient non-precious electrocatalysts with hierarchical porous structures for fuel cell applications.展开更多
BaTiO3 powders are prepared by sol-gel method by cotton template. Polypyrrole is prepared by chemical oxidation route in the emulsion polymerization system. Then BaTiO3- polypyrrole composites with different mixture r...BaTiO3 powders are prepared by sol-gel method by cotton template. Polypyrrole is prepared by chemical oxidation route in the emulsion polymerization system. Then BaTiO3- polypyrrole composites with different mixture ratios are prepared by as-prepared material. The structure, morphology, and properties of the composites are characterized with Infrared spectrum, X-ray diffraction, scanning electron microscope, and net-wok analyzer. The com- plex permittivity and reflection loss of the composites are measured at different microwave frequencies in S-band and C-band （0.03-6 GHz） employing vector network analyzer model PNA 3629D vector. The effect of the mass ratio of BaTiO3 to polypyrrole on the microwave loss properties of the composites is investigated. A possible microwave absorbing mechanism of BaTiOa-polypyrrole composite is proposed. The BaTiO3-polypyrrole composite can find applications in suppression of electromagnetic interference and reduction of radar signature.展开更多
Polypyrrole （PPY） microbelts are synthesized via the absorbent cotton template for the first time. PPY microbelts are characterized by Fourier transform infrared spectroscopy.The stability, the morphology and electr...Polypyrrole （PPY） microbelts are synthesized via the absorbent cotton template for the first time. PPY microbelts are characterized by Fourier transform infrared spectroscopy.The stability, the morphology and electrical conductivity of such microbelts are evaluated by means of scanning electron microscope, thermo-gravimetric analysis and four-probe con-ductivity. A possible mechanism for the formation of PPY microbelts are proposed. The conductivity is measured, and the conductivity variation mechanism of the PPY microbelts with the pyrrole monomer concentrations is analyzed.展开更多
Polypyrrole（PPy） shows a favorable application in the electromagnetic interference（EMI） shielding due to its good electrical conductivity and outstanding air stability.Conducting PPy films with high conductivity a...Polypyrrole（PPy） shows a favorable application in the electromagnetic interference（EMI） shielding due to its good electrical conductivity and outstanding air stability.Conducting PPy films with high conductivity and good adhesion were successfully polymerized on the surface of insulating epoxy resin substrates using chemical polymerization.The factors affecting the properties of PPy films,such as the surface morphology,adhesion between PPy film and substrate,electrical conductivity,EMI shielding effectiveness（SE）,were investigated.The adhesion was improved significantly through a three-step surface pretreatment of epoxy resin substrates including removing impurities,roughening,and surface modification with silane coupling agent.An enhancement in the conductivity of PPy films of about one order of magnitude was achieved by adding dopant in FeCl_3 solution.The higher the conductivity,the better the shielding effectiveness.Taking sodium p-toluenesulfonate doped PPy film as example,EMI SE was in the practically useful range of about 30 dB over a wide frequency range from 30 MHz to 1500 MHz.The PPy film samples were characterized by scanning electron microscopy （SEM）,infrared spectra（IR）,X-ray photoelectron spectroscopy（XPS） and the flange coaxial transmission device.The fourpoint probe method was used to measure conductivity of PPy films.展开更多
Three dimensional（3D） bioprinting, which involves depositing bioinks（mixed biomaterials） layer by layer to form computer-aided designs, is an ideal method for fabricating complex 3D biological structures. However,...Three dimensional（3D） bioprinting, which involves depositing bioinks（mixed biomaterials） layer by layer to form computer-aided designs, is an ideal method for fabricating complex 3D biological structures. However, it remains challenging to prepare biomaterials with micro-nanostructures that accurately mimic the nanostructural features of natural tissues. A novel nanotechnological tool, electrospinning, permits the processing and modification of proper nanoscale biomaterials to enhance neural cell adhesion, migration, proliferation, differentiation, and subsequent nerve regeneration. The composite scaffold was prepared by combining 3D bioprinting with subsequent electrochemical deposition of polypyrrole and electrospinning of silk fibroin to form a composite polypyrrole/silk fibroin scaffold. Fourier transform infrared spectroscopy was used to analyze scaffold composition. The surface morphology of the scaffold was observed by light microscopy and scanning electron microscopy. A digital multimeter was used to measure the resistivity of prepared scaffolds. Light microscopy was applied to observe the surface morphology of scaffolds immersed in water or Dulbecco＇s Modified Eagle＇s Medium at 37℃ for 30 days to assess stability. Results showed characteristic peaks of polypyrrole and silk fibroin in the synthesized conductive polypyrrole/silk fibroin scaffold, as well as the structure of the electrospun nanofiber layer on the surface. The electrical conductivity was 1 × 10^-5–1 × 10^-3 S/cm, while stability was 66.67%. A 3-（4,5-dimethyl-2-thiazolyl）-2,5-diphenyl-2-H-tetrazolium bromide assay was employed to measure scaffold cytotoxicity in vitro. Fluorescence microscopy was used to observe Ed U-labeled Schwann cells to quantify cell proliferation. Immunohistochemistry was utilized to detect S100β immunoreactivity, while scanning electron microscopy was applied to observe the morphology of adherent Schwann cells. Results demonstrated that the polypyrrole/silk fibroin scaffold was not cytotoxic and did not affect Schwann cell proliferation. Moreover, filopodia formed on the scaffold and Schwann cells were regularly arranged. Our findings verified that the composite polypyrrole/silk fibroin scaffold has good biocompatibility and may be a suitable material for neural tissue engineering.展开更多
Lithium/polypyrrole （Li/PPy） batteries were fabricated using lithium sheet as cathode, PPy as anode, microporous membrane polypropylene/polyethylene/polypropylene （PP/PE/PP） composite as separator and LiPF6/ethyle...Lithium/polypyrrole （Li/PPy） batteries were fabricated using lithium sheet as cathode, PPy as anode, microporous membrane polypropylene/polyethylene/polypropylene （PP/PE/PP） composite as separator and LiPF6/ethylene carbonate-dimethyl carbonate-methyl ethyl carbonate （EC-DMC-EMC） as electrolyte. Polypyrrole was prepared by chemical polymerization. Certain fundamental electrochemical performances were investigated. Properties of the batteries were characterized and tested by SEM, galvanostatic charge/discharge tests, cyclic voltammetry （CV）, and a.c. impedance spectroscopy. The influences of separator, morphology, and conductivity of PPy anode, cold-molded pressure, and electric current on the performances of the batteries were studied. Using PP/PE/PP membranes as separator, the battery showed good storage stability and cycling property. The conductivity of materials rather than morphology affected the behavior of the battery. The higher the conductivity, the better performances the cells had. Proper cold-molded pressure 20 MPa of the anode pellet would make the properties of the cells good and the fitted charge/discharge current was 0.1 mA. The cells showed excellent performance with 97%-100% coulombic efficiency. The highest discharge capacity of 95.2 mAh/g was obtained.展开更多
In this work hollow rectangular microtubes of polypyrrole(PPy)films were potentiostatically electrodeposited on magnesium alloy AZ91D in salicylate solution.The substrate was previously anodized under potentiostatic c...In this work hollow rectangular microtubes of polypyrrole(PPy)films were potentiostatically electrodeposited on magnesium alloy AZ91D in salicylate solution.The substrate was previously anodized under potentiostatic conditions in a molybdate solution in order to improve the adherence of polymer.Finally the duplex film was modified by the incorporation of silver species.The obtained coatings were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD)and X-ray photoelectron spectroscopies(XPS)and the antimicrobial activity against the bacteria Escherichia coli was evaluated.The corrosion protection properties of the coatings were examined in Ringer solution by monitoring the open circuit potential,polarization techniques and electrochemical spectroscopy(EIS).The duplex coating presents an improved anticorrosive performance with respect to the PPy film.The best results concerning corrosion protection and antibacterial activity were obtained for the silver-modified composite coating.展开更多
Fe2O3@polypyrrole nanotubes （Fe2O3@PPy nanotubes） have been successfully prepared by in-situ polymerization of the pyrrole on the surface of Fe2O3 nanotubes （Fe2O3-NTs）, via using L-Lysine as modified surfactant. ...Fe2O3@polypyrrole nanotubes （Fe2O3@PPy nanotubes） have been successfully prepared by in-situ polymerization of the pyrrole on the surface of Fe2O3 nanotubes （Fe2O3-NTs）, via using L-Lysine as modified surfactant. Hollow PPy nanotubes were also produced by dissolution of the Fe2O3 core from the core/shell composite nanotubes with 1 mol,L-1 HC1. Scanning electron microscopy（SEM）, transmission electron microscope （TEM）, selective-area electron diffraction （SAED）, X-ray powder diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and Fourier transform infrared spectroscopy（FT-IR） confirmed the formation of Fe2O3-NTs and Fe2O3@PPy core/shell nanotubes. Its catalytic properties were investigated under the ultrasound. The results of UV-vis spectroscopy （UV） demonstrated Rhodamine B （RhB） can be efficiently degraded by Fe2O3 @PPy nanotubes.展开更多
文摘Ammonia is toxic, colorless, and harmful to human health. It is important to detect ammonia effectively by gas sensors. In this paper, the mechanism of ammonia sensing on polypyrroles (PPy) films at room temperature has been investigated using a real-time, in-situ Fourier-transform infrared (FT-IR) spectroscopy. The introduction of ammonia results in a structural transformation of PPy films, which is confirmed by FT-IR spectrums. The structure and morphology of the products after the reaction between ammonia and PPy were investigated in detail by FT-IR spectrum and scanning electron microscope (SEM). It was found that the morphology of PPy films was changed to some degree after the reaction. Our results demonstrate that FT-IR spectroscopy is an extremely suitable technique for the characterization of the specific reaction between PPy and ammonia, since it allows monitoring the reaction at room temperature in real time. After the reaction between PPy and ammonia, the concentration of the carrier increases, and the resistance of PPy films decreases, indicating the sensitivity of detection of ammonia.
基金supported by the Fundamental Research Funds for the Central Universities and Heilongjiang Provincial Natural Science Foundation of China(Grant No.YQ2020E009).
文摘Robust, ultra-flexible, and multifunctional MXene-basedelectromagnetic interference (EMI) shielding nanocomposite filmsexhibit enormous potential for applications in artificial intelligence,wireless telecommunication, and portable/wearable electronic equipment.In this work, a nacre-inspired multifunctional heterocyclic aramid(HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite paper withlarge-scale, high strength, super toughness, and excellent tolerance tocomplex conditions is fabricated through the strategy of HA/MXenehydrogel template-assisted in-situ assembly of PPy. Benefiting from the"brick-and-mortar" layered structure and the strong hydrogen-bondinginteractions among MXene, HA, and PPy, the paper exhibits remarkable mechanical performances, including high tensile strength (309.7 MPa),outstanding toughness (57.6 MJ m−3), exceptional foldability, and structural stability against ultrasonication. By using the template effect ofHA/MXene to guide the assembly of conductive polymers, the synthesized paper obtains excellent electronic conductivity. More importantly,the highly continuous conductive path enables the nanocomposite paper to achieve a splendid EMI shielding effectiveness (EMI SE) of 54.1 dBat an ultra-thin thickness (25.4 μm) and a high specific EMI SE of 17,204.7 dB cm2g−1. In addition, the papers also have excellent applicationsin electromagnetic protection, electro-/photothermal de-icing, thermal therapy, and fire safety. These findings broaden the ideas for developinghigh-performance and multifunctional MXene-based films with enormous application potential in EMI shielding and thermal management.
基金supported by the Key Research and Development Program of Sichuan Province(Grant No.2023ZHCG0050)the Fundamental Research Funds for the Central Universities of China(Grant No.2682024QZ006 and 2682024ZTPY042)the Analytic and Testing Center of Southwest Jiaotong University.
文摘As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal conversion ability have received extensive attention.Meeting the aforesaid requirements simultaneously remains a huge challenge.In this research,the melamine foam(MF)/polypyrrole(PPy)nanowire arrays(MF@PPy)were fabricated via one-step electrochemical polymerization.The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays.Due to the upwardly grown PPy nanowire arrays,the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00°and outstanding stability under various harsh environments.Meanwhile,the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays.Furthermore,taking advantage of the high conductivity(128.2 S m^(-1)),the MF@PPy foam exhibited rapid Joule heating under 3 V,resulting in dynamic infrared stealth and thermal camouflage effects.More importantly,the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm^(2)g^(-1).Strong EMI shielding was put down to the hierarchically porous PPy structure,which offered outstanding impedance matching,conduction loss,and multiple attenuations.This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays,showing great applications in both military and civilian fields.
基金Funded by the National Natural Science Foundation of Hunan Province,Chinal(No.2021JJ60012)。
文摘To prepare a conductive polymer actuator with decent performance,a self-built experimental platform for the preparation of polypyrrole film is employed.One of the essential goals is to examine the mechanical characteristics of the actuator in the presence of various combinations of process parameters,combined with the orthogonal test method of"four factors and three levels".The bending and sensing characteristics of actuators of various sizes are methodically examined using a self-made bending polypyrrole actuator.The functional relationship between the bending displacement and the output voltage signal is established by studying the characteristics of the actuator sensor subjected to various degrees of bending.The experimental results reveal that the bending displacement of the actuator tip almost exhibits a linear variation as a function of length and width.When the voltage reaches 0.8 V,the bending speed of the actuator tends to be stable.Finally,the mechanical properties of the self-assembled polypyrrole actuator are verified by the design and fabrication of the microgripper.
基金the financial assistance from Science and Engineering Research Board(SERBCRG/2020/002818/MMM).
文摘Surface modification is found to be an effective way to control the initial degradation of Mg based biomedical alloys.The present study focuses on the modulation of in vitro and in vivo degradation behavior of Mg-Ce alloy through a stearic acid-treated polypyrrole coating,which developed superhydrophobic surface(contact angle∼153°)that drastically enhanced the corrosion resistance(more than 85%efficacy).Cerium addition to Mg alloy results basal texture strengthening and grain refinement,resulting in improved mechanical properties.All the specimens exhibited excellent antibacterial performance against gram-negative E.Coli(DH5α)and gram positive S.aureus bacteria.The oligodynamic effect of polypyrrole coating leads to complete bacterial mitigation.Non-toxic nature of the specimens was studied by MC3T3-E1 cell proliferation and differentiation in indirect cell culture method.Improved corrosion resistance of the coated specimen leads to enhanced cell proliferation and osteogenic differentiation.Hard tissue histology and micro-CT analysis exhibited higher fraction of newly formed callus tissues and highest bone-implant integration across the coated specimen,when implanted in rabbit femur.Efficacy of the material in fracture healing was evaluated by implanting bone plate and screw in a clinically fractured goat tibia.At 3 months,complete fracture healed with no vital organ toxicity was observed for the coated specimen.The present results suggest that Ce addition and polypyrrole coating are effective ways to modulate the corrosion and biocompatibility behavior making it a potential candidate for fracture fixation applications.
基金the project BRIGHT(Project reference:MERA-NET3/0004/2021)financed by national funds from FCT-Fundacao para a Ciência e a Tecnologia,I.P.,in the scope of the projects LA/P/0037/2020,UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures,Nanomodelling and Nanofabrication-i3N+6 种基金the support from the i3N-FCT-Portuguese Foundation for Science and Technology through the Ph.D.(Scholarship grant no.UI/BD/151288/2021)also partially supported by European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreements number 952169(SYNERGY,H2020-WIDESPREAD-2020-5,CSA)and 101008701(EMERGE,H2020-INFRAIA-2020-1),and 101070255(REFORM,HORIZON-C L4-2021-DIGITAL-EMERGING-01)also supported by LISBOA-05-3559-FSE-000007CENTRO-04-3559FSE-000094 operationsco-funded by the Lisboa 2020,Centro 2020 programme,Portugal 2020,European Union,through the European Social FundFunda??o para a Ciência e Tecnologia(FCT)Agência Nacional de Inovacao(ANI)。
文摘Textiles for health and sporting activity monitoring are on the rise with the advent of smart portable wearables.The intention of this work is to design wireless monitoring wearables,based on widely available textiles and low environmental impact production technologies.Herein we have developed a polymeric ink which is able to functionalize different types of textile fibers(including silver conducting fibers,cotton,and commercial textile)with poly pyrrole.These fibers were weaved together with a thinner silver conducting fiber and carbon fiber to form a touch-sensitive energy harvesting system that would generate an electric output when mechanical pressure is applied to it.Different prototypes were manufactured with loom weaving accessories to simulate real textile cloths.By simple touch,the prototypes produced a maximum voltage of 244 V and a maximum power density of 2.29 W m^(-2).The current generated is then transformed into a digital signal,which is further utilized for human motion or gesture monitorization.The system comprises a wireless block for the Internet of Things(IoT)applicability that will be eventually extended to future remote health and sports monitoring systems.
基金financially supported by the PhD research startup foundation of China West Normal University(No.22kE038)。
文摘Conductive hydrogels derived from natural polymers have attracted increasing attention in wearable electronics due to their inherent biocompatibility and sustainability.However,their poor mechanical strength,limited conductivity and unsatisfactory environmental adaptability remain significant challenges fo r practical applications.In this study,we report a high-performance gelatin-based conductive hydrogel(GPC)reinforced with polypyrrole-decorated cellulose nanofibers(PPy@CNF)and enhanced by a zwitterionic betaine/(NH_(4))_(2)SO_(4) solution.The PPy@CNF hybrid nanofillers were synthesized via in situ oxidative polymerization,enabling homogeneous dispersion of PPy along the CNF su rface.The incorporation of PPy@CNF significantly improved both mechanical strength and conductivity of the gelatin hydrogel.Meanwhile,the Hofmeister effect induced by(NH_(4))_(2)SO_(4) strengthened the hydrogel network,and the introduction of betaine further enhanced its anti-freezing and moisture-retention properties.The optimized GPC hydrogel exhibited a high tensile strength of 1.02 MPa,conductivity of 1.5 S·m^(-1),and stable performance at temperatures down to-50℃.Furthermore,it was successfully assembled into a wearable strain sensor for real-time human motion monitoring,and as an electrode layer in a flexible triboelectric nanogenerator(TENG),enabling biomechanical energy harvesting and self-powered sensing.This work provides a promising strategy for developing sustainable,multifu nctional hydrogels for next-generation weara ble electronics.
基金supported by the National Natural Science Foundation of China(Nos.52370070,and 52070047)。
文摘Reducing the highly toxic Cr(Ⅵ)to safe levels is a critical challenge in water treatment,essential for protecting both ecosystems and human health.In this study,we present a facile in situ polymerization approach to prepare polypyrrole-coated layered double hydroxide composites(PPy/NiFe LDHs).Compared with other LDHs and polypyrrole-based materials,the synthesized PPy/LDHs exhibit excellent adsorption performance under mildly acidic conditions,achieving a maximum Cr(Ⅵ)adsorption capacity of440.4 mg/g at pH 5.Notably,PPy/LDH effectively reduces Cr(Ⅵ)concentration from 10 mg/L to 0.028 mg/L,well below the maximum permissible level of 0.05 mg/L for drinking water.Additionally,PPy/LDH demonstrates durable stability;at pH 5,nickel and iron ions are not detected after adsorption,and trivalent chromium remains fixed on the material without re-release into the solution following reduction.The adsorption behavior and mechanistic analysis indicate that a combination of adsorption and reduction drives Cr(Ⅵ)removal by PPy/LDHs.This work offers an innovative approach to effectively remove the low concentrations of Cr(Ⅵ)from water,showing significant potential for efficient Cr(Ⅵ)remediation.
基金supported by the National Natural Science Foundation of China under Grant Nos.12102310 and U21A20113the Guangdong Basic and Applied Basic Research Foundation under Grant No.2020A1515110818+2 种基金the Inovation Team Project for Colleges and Universities of Guangdong Province under Grant No.2023KCXTD030the Key Project of Biomedicine and Health in Colleges and Universities of Guangdong Province under Grant No.2021ZDZX2055the Medical Science and Technology Research Fund of Guangdong Province under Grant No.A2022004.
文摘Proton exchange membrane fuel cells(PEMFCs)have gained increasing interests as promising power sources due to their ability to convert hydrogen and oxygen directly into electricity with high efficiency and zero greenhouse gas emissions.Bipolar plates(BPs)are considered as a critical component of PEMFCs,serving to collect current,separate gases,distribute the flow field,and conduct heat.This paper reviews the technical status and advancements in BP materials,with special focus on strategies for enhancing interfacial contact resistance(ICR)and corrosion resistance through conductive polymer(CP)coatings.First,commonly used BP materials in PEMFCs are summarized.Then,the advantages and limitations of various coatings for metallic BPs are discussed.Finally,recent progress in CP coatings for metallic BPs,aimed at achieving high corrosion resistance and low ICR,is comprehensively reviewed.
基金supported by National Natural Science Foundation of China(No.22309029)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515110089)+2 种基金Dongguan Social Development Technology Foundation(No.20231800907933)Collaborative Innovation Center of Marine Science and Technology of Hainan University(No.XTCX2022HYC14)Start-up Research Foundation of Hainan University(No.KYQD(ZR)-23069)。
文摘Active sulfur dissolution and shuttle effect of lithium polysulfides(LiPSs)are the main obstacles hindering the practical application of lithium-sulfur batteries(LSBs),which is primarily induced by the direct interaction between sulfur-loading cathode and liquid electrolyte.The introduction of functional interlayer within the separator and cathode is an effective strategy to stabilize the electrode/electrolyte interface reaction and improve the utilization rate of active sulfur.Herein,conductive composite nanofabrics(CCN)with multifunctional groups are employed as the interlayer of sulfur-loading cathode,in which the PMIA/PAN supporting fibers offer robust mechanical strength and high thermostable performance,and gelatin/polypyrrole functional fibers ensure high electrical conductivity and strong chemical interaction for LiPSs.As demonstrated by the experimental data and material characterizations,the presence of CCN interlayer not only blocks the shuttle behavior of LiPSs,but also strengthens the interface stability of both Li anode and sulfur-loading cathode.Interestingly,the assembled LSBs with CCN interlayer can maintain stable capacity of 686 mAh/g after 200 cycles at 0.5 A/g.This work will provide new ideas for the elaborate design of functional in terlayers/se para tors for LSBs and lithium metal batteries.
基金financially supported by the Natural Science Foundation of China(NSFC,No.22165032)Beijing Natural Science Foundation(No.2242032)
文摘The rational design of composition and microstructure is a proven strategy for developing multifunctional high-performance electromagnetic wave(EMW)absorbers.In this study,a sandwich-structured multilayer nanoplate-like Bi_(2)Fe_(4)O_(9)@Polypyrrole(BFO@PPy)heterostructure was successfully designed and fabricated using an efficient microwave hydrothermal method and an in situ polymerization process.Specifically,Bi_(2)Fe_(4)O_(9)enhances the chemical activity of ammonium persulfate,which in turn initiates the polymerization of pyrrole monomers,resulting in the formation of BFO@PPy heterostructures.The thickness of the PPy coating layer in the BFO@PPy composite can be precisely controlled at the nanoscale,optimizing electromagnetic parameters,conduction losses and interface polarization loss.The fabricated BFO@PPy composite achieves a minimum reflection loss(RL_(min))of-57.8 dB at a thickness of 2.5 mm and an effective absorption bandwidth(EAB)of 6.96 GHz.Furthermore,the EMW absorption performance and mechanism were systematically validated through theoretical calculations,radar cross-sectional simulations(RCS),and first-principles analysis.Notably,the RCS simulation of a 1:1 scale F-22 Raptor fighter model provides a realistic evaluation of the composite's EMW absorption potential in military applications.The efficient fabrication method and superior electromagnetic absorption performance make BFO@PPy a promising candidate for use in complex electromagnetic environments and military domains.Additionally,the BFO@PPy composite exhibits rapid electrothermal conversion at a low voltage(3V),achieving active infrared camouflage within a controllable temperature range,further highlighting its multifunctional properties.
文摘In this paper,we present a novel approach to enhancing the visible light photodetection efficiency of reduced graphene oxide(rGO)by incorporating polypyrrole(Ppy)nanoparticles sized between 126 nm and 1025 nm.The rGO and Ppy nanoparticles were synthesized via Hummer’s method and chemical polymerization,respectively.Characterization was performed using scanning electron microscope(SEM),transmission electron microscope(TEM),Raman spectroscopy,and optical measurements.The rGO/Ppy photodetector demonstrated a high photoresponsivity of 15 mA/W and a broad spectral response from 405 nm to 805 nm,indicating improved efficiency and versatility.This study high-lights the potential of tailored Ppy nanoparticle sizes in advancing rGO photodetectors for high-performance optoelectronic applications.
基金supported by the National Natural Science Foundation of China(21373042)~~
文摘The development of highly efficient catalysts for cathodes remains an important objective of fuel cell research. Here, we report Co3O4 nanoparticles assembled on a polypyrrole/graphene oxide electrocatalyst （Co3O4/Ppy/GO） as an efficient catalyst for the oxygen reduction reaction （ORR） in alkaline media. The catalyst was prepared via the hydrothermal reaction of Co2＋ ions with Ppy-modified GO. The GO, Ppy/GO, and Co3O4/Ppy/GO were characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The incorporation of Ppy into GO nanosheets resulted in the formation of a nitrogen-modified GO po-rous structure, which acted as an efficient electron-transport network for the ORR. With further anchoring of Co3O4 on Ppy/GO, the as-prepared Co3O4/Ppy/GO exhibited excellent ORR activity and followed a four-electron route mechanism for the ORR in alkaline solution. An onset potential of -0.10 V vs. a saturated calomel electrode and a diffusion limiting current density of 2.30 mA/cm^2 were achieved for the Co3O4/Ppy/GO catalyst heated at 800 ℃; these values are comparable to those for noble-metal-based Pt/C catalysts. Our work demonstrates that Co3O4/Ppy/GO is highly active for the ORR. Notably, the Ppy coupling effects between Co3O4 and GO provide a new route for the preparation of efficient non-precious electrocatalysts with hierarchical porous structures for fuel cell applications.
文摘BaTiO3 powders are prepared by sol-gel method by cotton template. Polypyrrole is prepared by chemical oxidation route in the emulsion polymerization system. Then BaTiO3- polypyrrole composites with different mixture ratios are prepared by as-prepared material. The structure, morphology, and properties of the composites are characterized with Infrared spectrum, X-ray diffraction, scanning electron microscope, and net-wok analyzer. The com- plex permittivity and reflection loss of the composites are measured at different microwave frequencies in S-band and C-band （0.03-6 GHz） employing vector network analyzer model PNA 3629D vector. The effect of the mass ratio of BaTiO3 to polypyrrole on the microwave loss properties of the composites is investigated. A possible microwave absorbing mechanism of BaTiOa-polypyrrole composite is proposed. The BaTiO3-polypyrrole composite can find applications in suppression of electromagnetic interference and reduction of radar signature.
基金This work was supported by the National Natural Science Foundation of China （No.20571066 and No.20871108）, the Program for the Top Scietutions of Shanxi, and the Program for the Top Young Academic Leaders of Higher Learning Institutions of Shanxi.nce and Technology Inovation Team of Higher Learning Insti
文摘Polypyrrole （PPY） microbelts are synthesized via the absorbent cotton template for the first time. PPY microbelts are characterized by Fourier transform infrared spectroscopy.The stability, the morphology and electrical conductivity of such microbelts are evaluated by means of scanning electron microscope, thermo-gravimetric analysis and four-probe con-ductivity. A possible mechanism for the formation of PPY microbelts are proposed. The conductivity is measured, and the conductivity variation mechanism of the PPY microbelts with the pyrrole monomer concentrations is analyzed.
基金supported by the National Natural Science Foundation of China(No.60071027)
文摘Polypyrrole（PPy） shows a favorable application in the electromagnetic interference（EMI） shielding due to its good electrical conductivity and outstanding air stability.Conducting PPy films with high conductivity and good adhesion were successfully polymerized on the surface of insulating epoxy resin substrates using chemical polymerization.The factors affecting the properties of PPy films,such as the surface morphology,adhesion between PPy film and substrate,electrical conductivity,EMI shielding effectiveness（SE）,were investigated.The adhesion was improved significantly through a three-step surface pretreatment of epoxy resin substrates including removing impurities,roughening,and surface modification with silane coupling agent.An enhancement in the conductivity of PPy films of about one order of magnitude was achieved by adding dopant in FeCl_3 solution.The higher the conductivity,the better the shielding effectiveness.Taking sodium p-toluenesulfonate doped PPy film as example,EMI SE was in the practically useful range of about 30 dB over a wide frequency range from 30 MHz to 1500 MHz.The PPy film samples were characterized by scanning electron microscopy （SEM）,infrared spectra（IR）,X-ray photoelectron spectroscopy（XPS） and the flange coaxial transmission device.The fourpoint probe method was used to measure conductivity of PPy films.
基金supported by the National Natural Science Foundation of China,No.81671823,81701835a grant from the National Key Research and Development Program of China,No.2016YFC1101603a grant from the Natural Science Research Program of Nantong of China,No.MS12016056
文摘Three dimensional（3D） bioprinting, which involves depositing bioinks（mixed biomaterials） layer by layer to form computer-aided designs, is an ideal method for fabricating complex 3D biological structures. However, it remains challenging to prepare biomaterials with micro-nanostructures that accurately mimic the nanostructural features of natural tissues. A novel nanotechnological tool, electrospinning, permits the processing and modification of proper nanoscale biomaterials to enhance neural cell adhesion, migration, proliferation, differentiation, and subsequent nerve regeneration. The composite scaffold was prepared by combining 3D bioprinting with subsequent electrochemical deposition of polypyrrole and electrospinning of silk fibroin to form a composite polypyrrole/silk fibroin scaffold. Fourier transform infrared spectroscopy was used to analyze scaffold composition. The surface morphology of the scaffold was observed by light microscopy and scanning electron microscopy. A digital multimeter was used to measure the resistivity of prepared scaffolds. Light microscopy was applied to observe the surface morphology of scaffolds immersed in water or Dulbecco＇s Modified Eagle＇s Medium at 37℃ for 30 days to assess stability. Results showed characteristic peaks of polypyrrole and silk fibroin in the synthesized conductive polypyrrole/silk fibroin scaffold, as well as the structure of the electrospun nanofiber layer on the surface. The electrical conductivity was 1 × 10^-5–1 × 10^-3 S/cm, while stability was 66.67%. A 3-（4,5-dimethyl-2-thiazolyl）-2,5-diphenyl-2-H-tetrazolium bromide assay was employed to measure scaffold cytotoxicity in vitro. Fluorescence microscopy was used to observe Ed U-labeled Schwann cells to quantify cell proliferation. Immunohistochemistry was utilized to detect S100β immunoreactivity, while scanning electron microscopy was applied to observe the morphology of adherent Schwann cells. Results demonstrated that the polypyrrole/silk fibroin scaffold was not cytotoxic and did not affect Schwann cell proliferation. Moreover, filopodia formed on the scaffold and Schwann cells were regularly arranged. Our findings verified that the composite polypyrrole/silk fibroin scaffold has good biocompatibility and may be a suitable material for neural tissue engineering.
基金the Foundation of Science and Technology Department of Heibei Province (No. 05547003D-4)the Foundation of the Education Department of Hebei Province, China (No. 2005356).
文摘Lithium/polypyrrole （Li/PPy） batteries were fabricated using lithium sheet as cathode, PPy as anode, microporous membrane polypropylene/polyethylene/polypropylene （PP/PE/PP） composite as separator and LiPF6/ethylene carbonate-dimethyl carbonate-methyl ethyl carbonate （EC-DMC-EMC） as electrolyte. Polypyrrole was prepared by chemical polymerization. Certain fundamental electrochemical performances were investigated. Properties of the batteries were characterized and tested by SEM, galvanostatic charge/discharge tests, cyclic voltammetry （CV）, and a.c. impedance spectroscopy. The influences of separator, morphology, and conductivity of PPy anode, cold-molded pressure, and electric current on the performances of the batteries were studied. Using PP/PE/PP membranes as separator, the battery showed good storage stability and cycling property. The conductivity of materials rather than morphology affected the behavior of the battery. The higher the conductivity, the better performances the cells had. Proper cold-molded pressure 20 MPa of the anode pellet would make the properties of the cells good and the fitted charge/discharge current was 0.1 mA. The cells showed excellent performance with 97%-100% coulombic efficiency. The highest discharge capacity of 95.2 mAh/g was obtained.
基金CONICET(PIP-112-201101-00055),ANPCYT(PICT-2012-0141)and Universidad Nacional del Sur(PGI 24/M127),Bahía Blanca,Argentina are acknowledged for financial support
文摘In this work hollow rectangular microtubes of polypyrrole(PPy)films were potentiostatically electrodeposited on magnesium alloy AZ91D in salicylate solution.The substrate was previously anodized under potentiostatic conditions in a molybdate solution in order to improve the adherence of polymer.Finally the duplex film was modified by the incorporation of silver species.The obtained coatings were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD)and X-ray photoelectron spectroscopies(XPS)and the antimicrobial activity against the bacteria Escherichia coli was evaluated.The corrosion protection properties of the coatings were examined in Ringer solution by monitoring the open circuit potential,polarization techniques and electrochemical spectroscopy(EIS).The duplex coating presents an improved anticorrosive performance with respect to the PPy film.The best results concerning corrosion protection and antibacterial activity were obtained for the silver-modified composite coating.
文摘Fe2O3@polypyrrole nanotubes （Fe2O3@PPy nanotubes） have been successfully prepared by in-situ polymerization of the pyrrole on the surface of Fe2O3 nanotubes （Fe2O3-NTs）, via using L-Lysine as modified surfactant. Hollow PPy nanotubes were also produced by dissolution of the Fe2O3 core from the core/shell composite nanotubes with 1 mol,L-1 HC1. Scanning electron microscopy（SEM）, transmission electron microscope （TEM）, selective-area electron diffraction （SAED）, X-ray powder diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and Fourier transform infrared spectroscopy（FT-IR） confirmed the formation of Fe2O3-NTs and Fe2O3@PPy core/shell nanotubes. Its catalytic properties were investigated under the ultrasound. The results of UV-vis spectroscopy （UV） demonstrated Rhodamine B （RhB） can be efficiently degraded by Fe2O3 @PPy nanotubes.
