Polymer Polypyrrole Research Articles

Adhesive and Conductive Fibrous Hydrogel Bandages for Effective Peripheral Nerve Regeneration.

Peripheral nerve injury is a common disease resulting in reversible and irreversible impairments of motor and sensory functions. In addition to conventional surgical interventions such as nerve grafting and neurorrhaphy, nerve guidance conduits are used to effectively support axonal growth without unexpected neuroma formation. However, there are still challenges to secure tissue-mimetic mechanical and electrophysiological properties of the conduit materials. Herein, the phenylborate-tethered hydrogel-assisted doping effect is elucidated on conductive polymers, enhancing peripheral nerve regeneration when used as a sutureless bandage on the injured nerve. The adhesive and conductive nerve bandage consists of biocompatible hyaluronic acid hydrogel microfibers produced by electrospinning, followed by in situ conductive polypyrrole polymerization on the fibrous mat. Particularly, phenylborate groups enable high adsorption of pyrrole without mechanical crack on the hydrogel network and allow tissue-like stretchability and on-nerve adhesiveness. In a rat crushed nerve injury model, the nerve bandage can effectively promote nerve regeneration through stable sutureless wrapping followed by great electrical transmission on the defect region, showing anatomical and functional recovery of the nerve tissues and preventing muscular atrophy. Such hydrogel fibrous bandages will be a promising surgical dressing to be combined with versatile biomedical devices/materials for peripheral nerve repair.

Dual 3D Structural Bi2WO6@Graphene Hydrogel Composites Modified Molecularly Imprinted Polymers: Application for Sensitive Photoelectrochemical Sensing of 4‐Nitrophenol in PM2.5

ABSTRACTThe accurate measurement of nitrophenols (NPs) in fine particulate matter (PM2.5) is critical because NPs are identified as the main constituents of brown carbon in PM2.5, which influence the global radiative forcing and regional climate. Herein, we presented a specific and ultrasensitive photoelectrochemical (PEC) sensor (MIPs/Bi2WO6@GH/ITO) for 4‐nitrophenol (4NP) detection by electrodepositing molecularly imprinted polymers (MIPs) polypyrrole on indium tin oxide coated glass (ITO) electrode modified with dual 3D structural Bi2WO6@graphene hydrogel (GH) composites. The composites were successfully synthesized through the simple one‐step hydrothermal method with 3D flower‐like Bi2WO6 efficiently distributed on the 3D porous networks of GH. Under optimum conditions, the PEC sensor exhibited a wide linear range of 5.0 × 10−12–1.0 × 10−7 M for 4NP with a low detection limit of 5.78 × 10−13 M. MIPs/Bi2WO6@GH/ITO was further successfully applied for 4NP assay in PM2.5. The results indicated that the developed PEC sensor had broad applications for NPs detection in the environmental fields.

Synthesis and characterization of polypyrrole polymer thin film and the effect of adding silver nanoparticles (PPY/AgNPs)

In this research, a chemical oxidative polymerization process was used to prepare polypyrrole (PPY). The characterization of polypyrrole thin films pure and dopped with silver nanoparticles (AgNPs) at different weight ratios of AgNPs (i.e., 5, 10, and 15 wt%) was studied. The thin films were prepared via the drop casting method and flung down on a clean glass substrate at room temperature. Using FT-IR, XRD, and AFM, the system and facet morphology of the thin films were investigated. FTIR analysis of undoped PPY powder revealed distinctive vibrational frequencies of PPY undoped. Strong absorption bands at 3653 cm-1 (N-H stretching), 2342 cm-1 (nitridation), and peaks at 1542, 1459 cm-1 (C=C, C=N vibrations) were observed. Other peaks at 1176 cm-1 (C-N stretching), 1039, 964 cm-1 (C-H vibrations), 893, 782 cm-1 (C-H bend deformation), 670 cm-1 (C-C deformation), and 590 cm-1 (polypyrrole presence) were identified. The results showed that the FT-IR spectra of pure ppy and the spectra of PPY/AgNPs composites were similar. The single XRD data also showed that ppy is amorphous and The distinctive peak of polypyrrole was found at (2θ) 24.35◦, indicating the short-range arrangement of PPy chains the interlayer distance (d) between the measured value of spacing for PPY was 3.6599 A0. Additionally, By using AFM, the parameters Ra, R.M.S, and G.S. were determined for PPY doped AgNPs thin films. These values increased with higher doping percentages. For undoped PPY thin film, values were (2.557nm, 3.299nm, 33.40nm) while for doped films with 5%, 10%, and 15% AgNPs, values were (3.397nm, 4.859nm, 46.12nm), (9.328nm, 11.90nm, 66.33nm), and (13.87nm, 19.28nm, 86.89nm) respectively. the AFM results for all thin films of PPY undoped and composites doped with silver nanoparticles (PPY/AgNPs) demonstrated that the values of grain size (G.S.) and root-mean-square (R.M.S.) roughness average (Ra) increase as the number of AgNPs increases.

Structural and linear/nonlinear optical characteristics of flexible polypyrrole/CuO polymeric composite films

The composite (PPy/CuO) films are created using the solution casting solution method by mixing the polymer polypyrrole (PPy) with copper oxide nanoparticles (CuONPs) at different concentrations of CuO (4%, 6% and 8%). The XRD confirms the effective fabrication of the composite (PPy/CuO). The impact of CuO on the optical and structural characteristics was studied. The addition of CuO enhances the refractive indices ([Formula: see text] of PPy from 1.42 for pure PPy to 1.55 for PPy with 4% CuO, and further to 1.69 for PPy with 8% CuO. The dispersion energy of pure polypyrrole (PPy) is 4.55[Formula: see text]eV, which increased to 5.31[Formula: see text]eV when doped with 4% CuO. Furthermore, the increasing of CuO concentration to 6% and 8% resulted in higher dispersion energies, respectively, of 5.87 and 6.14[Formula: see text]eV. The oscillation energy [Formula: see text] decreased from 4.43[Formula: see text]eV for PPy to 3.76, 3.41 and 3.25[Formula: see text]eV for PPy/4%CuO, PPy/6%CuO and PPy/8%CuO, correspondingly. The introduction of CuO into the PPy polymer results in modifications to its optical characteristics. Additionally, there was an observed rise in the plasma frequency from [Formula: see text][Formula: see text][Formula: see text] for PPy to [Formula: see text][Formula: see text][Formula: see text] for PPy/8%CuO. The findings of this study offer empirical support for the possible use of PPy/CuO films in optical devices.

Improving the performance of microbial fuel cell stacks via capacitive-hydrogel bioanodes

We constructed a capacitive bioanode PPy/EABs@Mag-CLF/SA for circumventing the bioelectrochemical reaction shift during voltage reversal of series-stacked MFC. Sodium alginate hydrogel (SA) was made as the binder, in which the conducting polymer polypyrrole (PPy) was doped. Biomagnetic carbonized loofah particles (EABs@Mag-CLF) cultured in a pulsating fluidized bed were encapsulated by hydrogel as the anode biocatalyst. The pseudocapacitive material PPy combined with the biofilm capacitance attached to 3D biochar particles together constructed the biocapacitor anode with an energy storage function. The result showed that the power density of PPy100/EABs@Mag-CLF100/SA (71.88 W/m3) was 1.87 times more than PPy100/EABs@Mag-CLF50/SA. In the charge/discharge test (C60/D60), the stored charge Qs of PPy100/EABs@Mag-CLF100/SA (460.97 C/m2) was 3.74 times greater than that of PPy20/EABs@Mag-CLF100/SA. Stacked MFCs equipped with PPy100/EABs@Mag-CLF100/SA anodes had a smaller threshold resistance (Rthreshold) and recovered their performance even after a voltage reversal. This can provide an ideal energy solution for intermittently operating microelectronic devices.

Engineering Delocalized Polarizations in Metal Oxide Electrodes with Conducting Polymers for Efficient and Durable Water-Splitting.

Oxygen evolution reaction is a pivotal anodic reaction for electrolysis, however, it remains the obstacle from its sluggish reaction kinetics originating from multiple electron transfer pathways at electrochemical interfaces. Especially, it remains a challenge to achieve stable operation at elevated current densities as electrodes suffer oxidative environment in corrosive conditions. Herein, we report that the conducting polymer polypyrrole electrodeposited Pr0.7Sr0.3CoO3 perovskite oxides for durable oxygen evolution electrodes. We found that the conducting polymer electrodeposited oxides exhibited a highly durable electrochemical oxygen evolution performance maintaining >99 % of initial activities during the accelerated durability test. Meanwhile, bare metal oxides presented significant performance drops (<6 % of initial activities) over the consecutive 20,000 accelerated durability test. High-resolution transmission electron microscope images identified the maintenance of high crystallinity of the heterostructure, suggesting that the electrodeposited pPy clusters can effectively delocalize highly polarized electrodes preventing material corrosion. The overall water electrolysis experiments further demonstrated that the heterostructure showed excellent stability at the high current density of 100 mA cm-2 over 700 hours. This marks the first report of the delocalized polarization benefiting from conducting polymers for durable oxygen evolution for perovskite oxides, suggesting great potential for scalable water electrolysis.

Multifunctional green synthesized silver nanoparticle and polypyrrole-based e-textile for wearable thermoregulation applications

Electronic textiles (e-textiles) build upon existing technologies to develop truly smart textiles: garments that sense, react, and adapt. Thermoregulatory e-textiles are an area of significant interest across the field. Designing e-textiles that satisfy electrical performance and simple construction is a significant challenge. To address these issues, a simple dip-coating and in-situ polymerization method was used to develop the first example of a thermoregulatory e-textile using green synthesized silver nanoparticles (AgNP) and polypyrrole (Ppy), based on the method previously reported (Naysmith, A.; Mian, N.S.; Rana, S. Development of conductive textile fabric using Plackett–Burman optimized green synthesized silver nanoparticles and in situ polymerized polypyrrole. Green Chemistry Letters and Reviews 2023, 16 (1)). This methodology was optimized using a Taguchi statistical design determining the optimal AgNP-Ppy synthesis method to obtain high performance Joule heating e-textiles, novel within the field of e-textiles. Reactant concentration and reaction time had the largest effects on the electrical resistance of subsequent e-textiles. The result is the first example of an e-textile heater based on green synthesized AgNPs. The e-textile demonstrated exceptional Joule heating (120°C), low electrical resistance (37 Ω), resistive temperature sensing behavior (negative TCR = −0.0046), and increased thermal conductivity (19.55 l (Wm−1 K−1)); the strain sensing behavior (gauge factor = −0.07). This work extends knowledge of the development and challenges within e-textile technologies as the field creates the next generation of textiles.

Tailoring polypyrrole morphology and electronic properties through CTAB-SDS self-assembly

This study explores the polymerization of polypyrrole (PPy) within a self-assembled catanionic surfactant composed of cetyltrimethylammonium bromide (CTAB) - sodium dodecyl sulfate (SDS), aiming to control its morphology and electronic properties. The research systematically investigates how varying the compositions of CTAB and SDS surfactants influence the structural and electronic characteristics of PPy. Our findings indicate that the surfactant composition predominantly impacts the shape of PPy rather than its crystallinity. Despite the absence of significant crystallinity, variations in surfactant composition notably alter the electronic properties of PPy. Specifically, an increase in CTAB content results in electrical conductivity increasing from 0.34 to 0.01 S/m. Conversely, higher SDS content enhances the bipolaron-to-polaron ratio, particularly in the C−H deformation region, contributing to improved electronic characteristics. Additionally, packing density analysis reveals that the ordered or disordered acyl chain arrangement within the catanionic surfactant system varies significantly with surfactant composition, further influencing the morphology and electronic properties of PPy. These findings provide valuable pave for designing conductive polymers with tailored electronic properties by a catanionic surfactant, where precise control over such properties is crucial.

A Reactor based on P‐N Heterojunction of Polypyrrole and Porous Silicon for Photocatalytic and Electro‐assisted Photocatalytic Performance

AbstractIn this work, a photoelectrochemical reactor with an anode based on hybrid structure between conducting polymer polypyrrole (PPy) and porous silicon (PSi) was fabricated and utilized to evaluate the photocatalysis and electro‐assisted photocatalysis for degradation of rhodamine B (RhB) solution. The PSi was made of n‐type silicon single‐crystal wafer by the metal‐assisted chemical etching (MACE). The anode PPy/PSi formed following a polymerization of the PPy on the PSi from the vapour‐phase route using oxidant FeCl3. Typical material characterizations of the PPy, PSi and PPy/PSi were investigated via scanning electron microscope (SEM), and spectroscopies of Fourier‐transform infrared (FTIR), Raman scattering and UV‐vis. Under visible light radiation (halogen light with the wavelength region of 400–700 nm), photocatalytic and electro‐assisted photocatalytic processes of the reactor were conducted by degradation of the RhB solution. A heterojunction (p‐n) of the PPy/PSi was proposed to explain the efficient catalytic performance of the reactor.

Study of Ion-to-Electron Transducing Layers for the Detection of Nitrate Ions Using FPSX(TDDAN)-Based Ion-Sensitive Electrodes.

The development of ISE-based sensors for the analysis of nitrates in liquid phase is described in this work. Focusing on the tetradodecylammonium nitrate (TDDAN) ion exchanger as well as on fluoropolysiloxane (FPSX) polymer-based layers, electrodeposited matrixes containing double-walled carbon nanotubes (DWCNTs), embedded in either polyethylenedioxythiophene (PEDOT) or polypyrrole (PPy) polymers, ensured improved ion-to-electron transducing layers for NO3- detection. Thus, FPSX-based pNO3-ElecCell microsensors exhibited good detection properties (sensitivity up to 55 mV/pX for NO3 values ranging from 1 to 5) and acceptable selectivity in the presence of the main interferent anions (Cl-, HCO3-, and SO42-). Focusing on the temporal drift bottleneck, mixed results were obtained. On the one hand, relatively stable measurements and low temporal drifts (~1.5 mV/day) were evidenced on several days. On the other hand, the pNO3 sensor properties were degraded in the long term, being finally characterized by high response times, low detection sensitivities, and important measurement instabilities. These phenomena were related to the formation of some thin water-based layers at the polymer-metal interface, as well as the physicochemical properties of the TDDAN ion exchanger in the FPSX matrix. However, the improvements obtained thanks to DWCNT-based ion-to-electron transducing layers pave the way for the long-term analysis of NO3- ions in real water-based solutions.

Electronically Conductive Polymer Enhanced Solid-State Polymer Electrolytes for All-Solid-State Lithium Batteries

All-solid-state lithium batteries (ASSLBs) have gained enormous interest due to their potential high energy density, high performance, and inherent safety characteristics for advanced energy storage systems. Although solid-state ceramic (inorganic) electrolytes (SSCEs) have high ionic conductivity and high electrochemical stability, they experience some significant drawbacks, such as poor electrolyte/electrode interfacial properties and poor mechanical characteristics (brittle, fragile), which can hinder their adoption for commercialization. Typically, SSCE-based ASSLBs require high cell stack pressures exerted by heavy fixtures for regular operation, which can reduce the energy density of the overall battery packages. Polymer–SSCE composite electrolytes can provide inherently good interfacial contacts with the electrodes that do not require high cell stack pressures. In this study, we explore the feasibility of incorporating an electronically and ionically conducting polymer, polypyrrole (PPy), into a polymer backbone, polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP), to improve the ionic conductivity of the resultant polymer–SSCE composite electrolyte (SSPE). The electronically conductive polymer-incorporated composite electrolyte showed superior room temperature ionic conductivity and electrochemical performance compared to the baseline sample (without PPy). The PPy-incorporated polymer electrolyte demonstrated a high resilience to high temperature operation compared with the liquid-electrolyte counterpart. This performance advantage can potentially be employed in ASSLBs that operate at high temperatures. In our recent development efforts, SSPEs with optimal formulations showed room temperature ionic conductivity of 2.5 × 10−4 S/cm. The data also showed, consistently, that incorporating PPy into the polymer backbone helped boost the ionic conductivity with various SSPE formulations, consistent with the current study. Electrochemical performance of ASSLBs with the optimized SSPEs will be presented in a separate publication. The current exploratory study has shown the feasibility and benefits of the novel approach as a promising method for the research and development of next-generation solid composite electrolyte-based ASSLBs.

Polypyrrole as photo-thermal-assisted modifier for BiVO4 photoanode enables high-performance photoelectrochemical water splitting

Herein, iron nickel oxide (FeNiOx) and conductive polymer polypyrrole (PPy) with excellent hole transport property and catalytic oxidation ability combine with bismuth vanadate (BiVO4) based photoanode to obtain a remarkable improvement of photocurrent density. More importantly, due to the photo-thermal effect of PPy, the operating temperature of the photoanode reaches 323.15 K under AM 1.5G illumination without infrared light source, thus activating the photoanode surface and accelerating the water splitting reaction. As a result, when the temperature of electrolyte reaches 323.15 K, the photocurrent density of BiVO4/FeNiOx/PPy photoanode achieves 6.91 mA cm−2 at 1.23 V versus reversible hydrogen electrode (vs. RHE), which is 3.04 folds of pristine BiVO4 (2.27 mA cm−2). Such a photo-thermal-assisted enhancement strategy based on the temperature sensitivity of BiVO4 provides a new way for the breakthrough of the performance bottleneck of BiVO4 photoanode and the design of the next generation PEC catalyst materials.

Extraordinary Hydrogen Evolution and Oxygen Evolution Reaction Activity From PPy@FeCo-LDH/NF Bifunctional Electrocatalyst in Alkaline Solution

Alkaline water electrolysis is a promising technique for the production of hydrogen and oxygen. Nevertheless, the development of low-cost, high-activity metal-based electrocatalysts that can effectively catalyze the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) remains a significant challenge. Herein, we polymerized Polypyrrole (PPy) with FeCo layered double metal hydroxide grown in situ on nickel foam (NF) (FeCo-LDH/NF) by electrochemical polymerization to acquire composite material PPy@FeCo-LDH/NF. As a promising electrocatalyst with dual functionality for the HER and OER, the HER overpotential of PPy@FeCo-LDH/NF was 153 mV, and the OER overpotential was 245 mV at a current density of 10 mA·cm−2. It was because that PPy increased the number of active adsorption sites, which in turn regulated the ion transfer rate between the electrolyte and the prepared catalyst. At the same time, after 24 h of stability testing, the HER and OER capacitance retention rates were 96.7% and 97.1%, respectively.

Effect of polypyrrole incorporation amounts on the optical and electrical properties of PVA/CMC blended polymer for optoelectronic applications

In the present work, hybrid flexible blended polymers of polypyrrole (PPy)/polyvinyl alcohol (PVA)/carboxymethyl cellulose (CMC); PVA/CMC/x wt % PPy; were constructed as promising blended materials to be used in various optoelectronics applications. X-ray diffraction and scanning electron microscopy techniques were used to investigate the structure and the surface morphology of polymer nanocomposites. The doped blends have better absorption of the three types of ultraviolet (UVA, UVB, and UVC), as well as the visible spectrum. The transmittance values in the visible range dropped from 90 % to 63 % as the PPy concentration reached 0.5 wt%. At x = 0.5, the minimum direct and indirect optical band gap energy values of (4.82, 4.39, 4.23) eV and (3.76, 3.84, 3.62, 2.93) eV, respectively, were obtained. The incorporation of PPy into the PVA/CMC blend led to a regular rise in the refractive index value within the visible range. The blend doped with 0.5 wt % PPy exhibited the highest optical dielectric constant values within the visible range. The enhancement/reduction in the fluorescence intensity depended on the excitation wavelength and the amount of PPy doping in the blended polymers. The effect of voltage, temperature and the amount of PPy doping on the current behavior of the resulting electric current in all blends was explored. The ohmic and nonohmic natures and the charge transport mechanisms of different blends were determined.

Effective removal of uranium (VI) with a SDBS doped PPy-SUS304 electrode from alkaline wastewater using electrodeposition strategy

The immobilization of uranium in nuclear wastewater is of paramount importance for environmental and human health. However, there is a paucity of research on the immobilization of uranium in alkaline wastewater, particularly with regards to the application of novel electrodes. This article presents the utilization of an electrochemically polymerized polypyrrole stainless steel (PPy-SUS304) electrode for the effective electrochemical deposition and removal of uranium from alkaline wastewater containing uranium. According to the electrodeposition results, the uranium deposition efficiency of the novel electrode reached 96.82 %, with a uranium deposition rate of 0.048 mg U/(h·cm2) and a charge efficiency of 0.055 mg U/C. These findings demonstrate the successful electrochemical reduction of UO2(CO3)34- in alkaline uranium-containing wastewater using the novel electrode, resulting in improved charge deposition efficiency. The electrode surface products were investigated using scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and X-Ray Photoelectron Spectroscopy (XPS). The SEM and EDS results demonstrate the formation of a uniform PPy film on the surface of SUS304. In addition, the White light interferometer (WLI) test reveals that the PPy-SUS304 electrode exhibits increased roughness compared to the SUS304 electrode. The XPS results revealed that the electrode surface products of PPy-SUS304 were actually U compounds constituted of U(IV) oxides or hydroxides. This study provides a new perspective for the development of novel electrodes to suppress side reactions and efficiently recover uranium from alkaline uranium-containing wastewater.

Smart versatile hydrogels tailored by metal-phenolic coordinating carbon and polypyrrole for soft actuation, strain sensing and writing recognition

Biomimetic intelligent conductive hydrogels integrating flexibility, signal sensing, and contactless actuation has become ideal candidates for the production of electronic skins, wearable devices, and soft robotics. However, the development of multifunctional smart hydrogels capable of both sensing and actuating simultaneously to enhance intelligent interaction interfaces remains a significant challenge. Herein, a multifunctional hydrogel composite with integrated sensing and actuating capabilities is proposed through the incorporation of Fe3+-tannic acid (TA) coordination compound-coated carbon nanotubes (Fe-TA@SWNT) and the in-situ formation of conductive polymer polypyrrole (PPy) inside the hydrogel networks composed of carboxymethylcellulose (CMC) and a copolymer of acrylic acid (AA) and [2-(methacryloyloxy) ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide (SBMA). Benefiting from multiple effective dynamic interactions within the internal matrix, the prepared hydrogel exhibits excellent stretchability (1283.42 % elongation) and toughness (1.11 MJ/m3). Additionally, the catechol groups carried by Fe-TA@SWNT, along with the zwitterionic monomer SBMA, provide the hydrogel with repeatable self-adhesion performance. Based on the outstanding photothermal effect of Fe-TA@SWNT and PPy, the hydrogel demonstrates reversible and stable photothermal responsiveness, exhibiting exceptional actuation performance under near-infrared (NIR) radiation. As a strain sensor, the hydrogel shows excellent sensitivity (GF = 3.32), rapid response time, and reliable stability, enabling precise monitoring of various physiological signals in the human body, including joint movements, facial expressions, and heartbeats. Therefore, this work significantly expands the application prospects of multifunctional smart hydrogels in fields of wearable electronics, soft robotics, and remote light-controlled devices.

HiPSC-derived cardiomyocyte cultivation and measurement of electrophysiological properties on gelatine/glucose/polypyrrole scaffold

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): EU Horizon 2020 Framework Programme (H2020) under Grant agreements No. 953138 (EMAPS-Cardio) Purpose Cardiotoxicity is one of the main side effects limiting development of new medicines and resulting in withdrawal of drugs from the market. There are different mechanisms of drug-induced cardiotoxicity, including arrhythmia, disruption of mitochondria function, apoptosis, altered growth factor signalling [1]. Heart on a chip model for drug testing seems attractive approach to evaluate the possible cardiotoxic effects on cell biological, but mostly electrophysiological properties. Our aim was to create a 3D system with a biocompatible scaffold, coated with a conductive layer, suitable for culturing and maturation of human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) and compatible with electrophysiology parameter measurement techniques. Methods Elastic scaffold was fabricated by electrospinning of gelatin-glucose microfibers followed by the vapor-phase and electrochemical deposition of conductive polymer polypyrrole (PPy) to create electroconductive layer. hiPSC-CMs at different maturation levels (at 6 vs 14 weeks) were used to test biocompatibility of the scaffold. To increase cell attachment, scaffold was treated with 0.1 M HCl and coated with Geltrex. Cells were stained with fluorescent dyes (Calcein AM, DAPI). Electrophysiological properties were analysed using intracellular calcium imaging (Cal520) and action potential recordings with sharp electrodes. HiPSC-CMs on coverslips were used as a 2D control. Results Calcein AM staining showed that high number of hiPSC-CMs attached to gelatine/glucose/PPy scaffold proving that the scaffold is biocompatible and cells remain viable even after long term incubation (&amp;gt; 2 weeks). HiPSC-CMs at lower maturity (6 weeks) had better attachment properties to it, indicating that more mature cardiomyocytes (14 weeks) gradually lose their capacity to attach to PPy surface. Intracellular calcium imaging showed that both types of cells generated synchronous spontaneous calcium oscillations on gelatine/glucose/PPy scaffolds. Action potential recordings in 3D were similar to those in 2D, and confirmed differences in hiPSC-CMs maturation levels – at lower maturation level hiPSC-CMs had lower upstroke velocity as compared to more matured hiPSC-CMs. Conclusions Gelatine/glucose/PPy scaffold is biocompatible for hiPSC-CMs cultivation, and suitable for evaluation of cardiomyocyte electrophysiological properties. Such electromechanoactive scaffold can be further employed for development of heart-on-a-chip model.

UV‐Curable 3D‐Printable Microwave‐Absorbing Material with a Sword‐Sheath Structure Based on Multiwalled Carbon Nanotube/Polypyrrole Nanotube/Fe3O4 Composites

Multiwalled carbon nanotube (MWCNT)/polypyrrole nanotube (PPyNT)/triiron tetraoxide (Fe3O4) composites with a sword‐sheath structure are added to a UV‐curable resin to form a unique highly microwave‐absorbing material with a low absorbent content. Specifically tailored for high‐precision stereolithography three‐dimensional (3D) printers, the low absorbent content ensures an efficient curing and molding of the photosensitive resin. The conducting polymer polypyrrole is coated on the MWCNTs via free‐radical polymerization, forming a sheath structure. The initiator of the free‐radical polymerization, FeCl3, is converted into Fe3O4 and loaded onto the sheath structure. This ternary composite material is uniformly dispersed in the photosensitive resin with interconnected sword‐sheath structures, ensuring a favorable dielectric loss performance even at a low absorbent content. Importantly, the material exhibits both dielectric loss and magnetic loss properties. Using a UV‐cured microwave‐absorbing material with an absorbent content of 0.5 wt%, an electromagnetic loss of −22.5 dB can be achieved with a thickness of 1 mm. This UV‐cured microwave‐absorbing material facilitates the high‐precision 3D printing of microwave structures with various intricate shapes, broadening the application scope of microwave‐absorbing materials.

Conductive polypyrrole: synthesis, characterization, thermal, and electrical properties for different applications

Pyrrole monomer (mPPy) in an aqueous solution was used to create the conductive polymer polypyrrole (a homo-PPy) using a chemical oxidative polymerization process over a period of several hours at room temperature. Ferric chloride (FeCl3) oxidant was used, and sodium dodecyl sulphate (C12H25NaO4S), a surfactant. The produced PPy samples were characterized using a variety of methods, including X-ray diffraction (XRD), the Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), Differential Thermal analysis (DTA), Thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). SEM images revealed that nanoparticles of a homo-PPy with radii of 60–90 nm were well evenly distributed in the structure. The thermal stability and electrical conductivity of homo-PPy nanoparticles were observed to rise with a solvent ethylene glycol. As temperature rises, the conductivity of homo-PPy samples is significantly raised, and electrical conductivities ranging from.0.44 to 2.2 (Ω.m)−1. Results from FTIR and XRD analysis confirmed the structural formation of a homo-polypyrrole during synthesis from pyrrole monomer. Because of their improved electrical conductivity and thermal stability, homo-PPy nanoparticles have potential applications in energy storage, adsorption and contamination elimination, electromagnetic protection, and resistance to corrosion.

Layer-by-layer assembling redox wood electrodes for efficient energy storage

The exploration of redox-active organic materials and low tortuous thick-electrodes is attractive for energy storage. The in-situ valorized lignin on raw wood surface accompanied by layer-by-layer deposition of electro-active materials endow such spatially distributed wood electrodes with high specific capacitance. Here, we report a layer-by-layer assembled ca.1.5 mm-thick redox wood hybrid electrode with 20 mg cm-2 electro-active mass loading for efficient energy storage. The in-situ modified surface lignin in treated wood (TrW) holds promise as redox-active material with enriched nanoporosity, carbonyl functionalities, and multi-phase ionic transport structure. The carbon nanotubes (CNTs) networking with in-situ polymerized polypyrrole (PPy) nanorods three-dimensionally in the lumen of TrW afford a wool-like, highly porous nanostructure. Such a hierarchical structured PPy@CNTs@TrW electrode offers a high areal capacitance of 1.46 F cm-2 with an extraordinary energy density of 0.983 mWh cm-3 (3.68 Wh kg-1) and power density of 5.4 mW cm-3 (20.25 W kg-1). Here, the valorized surface lignin contributes contributes to electrochemical energy storage accompanied by spatially distributed PPy@CNTs in low tortuous electrodes. The electrode offers extremely low electrochemical impedance of 0.61 Ω electrode resistance and 1.57 Ω electrolyte resistance. The hybrid wood electrode showcases even higher conductivity and energy/power density than thin carbonized wood and other state-of-the-art thin electrodes made of highly conductive three-dimensional networks. This work highlights the potential of in-situ valorized lignin in developing high-performance eco-friendly thick-electrodes for electrochemical energy storage applications.