Polyaniline Chains Research Articles

Flexible Artificial Tactility with Excellent Robustness and Temperature Tolerance Based on Organohydrogel Sensor Array for Robot Motion Detection and Object Shape Recognition.

Hydrogel-based flexible artificial tactility is equipped to intelligent robots to mimic human mechanosensory perception. However, it remains a great challenge for hydrogel sensors to maintain flexibility and sensory performances during cyclic loadings at high or low temperatures due to water loss or freezing. Here, a flexible robot tactility is developed with high robustness based on organohydrogel sensor arrays with negligent hysteresis and temperature tolerance. Conductive polyaniline chains are interpenetrated through a poly(acrylamide-co-acrylic acid) network with glycerin/water mixture with interchain electrostatic interactions and hydrogen bonds, yielding a high dissipated energy of 1.58MJ m-3, and ultralow hysteresis during 1000 cyclic loadings. Moreover, the binary solvent provides the gels with outstanding tolerance from -100 to 60°C and the organohydrogel sensors remain flexible, fatigue resistant, conductive (0.27 S m-1), highly strain sensitive (GF of 3.88) and pressure sensitive (35.8 MPa-1). The organohydrogel sensor arrays are equipped on manipulator finger dorsa and pads to simultaneously monitor the finger motions and detect the pressure distribution exerted by grasped objects. A machine learning model is used to train the system to recognize the shape of grasped objects with 100% accuracy. The flexible robot tactility based on organohydrogels is promising for novel intelligent robots.

Effect of Phytic Acid, Tin Oxide and Graphite Incorporation in Polyaniline Semiconductive Ink

Enhanced electrical conductivity and pressure sensing functionalities of phytic acid-doped polyaniline ink (PPhyA) incorporated with SnO2 (PPhyAS) and graphite flakes (PPhyAG) as reported in our previous article, encouraged us to explore the electrical conduction mechanism and associated optical properties. In order to realize the enhanced electrical conduction in the reported inks, detailed studies were carried out in our research described here in comparison with normal HCl-doped polyaniline (PANI). This can be attributed to the formation of a highly ordered molecular arrangement with high crystallinity, a change in the hopping pathway between two adjacent molecules and the hopping activation energy of the PANI chain in the phytic acid-doped ink systems. Optical parameters, such as absorption edge, Urbach energy, refractive index, extinction coefficient, optical conductivity and optical dielectric constants, were estimated from the result of UV-Vis spectroscopy. The results of these studies showed enhancement of the optical properties of the phytic acid-doped ink systems (PPhyA, PPhyAS and PPhyAG) in the low photon energy range as compared to HCl-doped PANI. Phytic acid-doped ink systems are paintable on a variety of flexible surfaces, such as paper and plastics. Hence, we suggest that the phytic acid-doped ink systems have a great potential for developing flexible and foldable circuitry for infrared optics and remote sensing.

Energy-safety balanced composites of attractive cyclic nitramines with polyaniline

Composite microcrystals of the cyclic nitramines 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (ε-CL-20), 1,3,5-trinitro-1,3,5-triazinane(RDX), 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (β-HMX), and cis-1,3,4,6-tetranitrooctahydroimidazo-[4,5-d]imidazole (BCHMX) with polyaniline (PANi) have been prepared and thoroughly characterized in terms of morphology and phase purity. PANi outperformed other conducting polymers in terms of selectivity towards NAs due to its better interaction with NAs, low production cost, and ease of preparation. The bonding of nitramines with the polymeric PANi chain has been examined by means of Fourier transform infrared (FTIR), Raman spectroscopy methods, and fluorescence quenching; the Raman spectrum has shown the laser sensitivity of these microcrystals. Powder X-ray diffraction results have shown changes in polymorph modifications in CL20 (from ɛ to β) and HMX (from β to α) during the preparation of the composites, which have also been confirmed by spectral and differential thermal analysis techniques. The structural orientations found in these composites significantly stabilize nitramines against impact; their detonation properties have slightly deteriorated, but the PANi electrical conductivity has strongly increased their electric-spark sensitivity. The above properties of the prepared composites determine their potential use mainly as parts of the electric or laser impulse initiators, having “a green character”, for various charges.

Advanced electrochemical synthesis and characterization of Al2O3 nanoparticles embedded in polyaniline matrix for optoelectronic applications

Nanocomposite materials, featuring conducting polymers and aluminum oxide nanoparticles (Al2O3-NPs), are revolutionizing various fields including biomedicine, optoelectronic devices, and dye adsorption. In this study, we report on the synthesis of Al2O3 nanoparticles embedded in a Polyaniline (PANI) matrix for the fabrication of Al2O3/PANI nanocomposite films. The electrodeposition method was employed to deposit these films onto ITO-glass substrates, with concentrations ranging from 5 % to 20 %. The optical properties of the nanocomposites were analyzed using UV–Vis spectroscopy, allowing the determination of the refractive index and absorption coefficients. In addition, the Scherrer equation was used to calculate the average crystallite size, providing insight into the microscopic, ordered regions within the material. With increasing nanoparticle concentration in PANI-Al2O3 nanocomposites, Tauc plots revealed an increase in energy band gaps from 3.70 eV to 3.85 eV. Additionally, optical bandgap energies increased in PANI- Al2O3 nanocomposites, while electrical conductivities decreased with higher Al2O3 NPs content. Incorporation of Al2O3 NPs reduced the degree of conjugated π-bonds in PANI and disrupted the ordered structure of polymer chains. Moreover, the SEM analysis confirmed that the nanocomposite films had a dense, fiber-like structure. Further analysis of FTIR and XRD data revealed interactions between Al2O3 nanoparticles and PANI chains. At lower concentrations, minimal interaction was observed, while higher concentrations resulted in enhanced molecular interactions, leading to improved chain stretching, molecular packing, and larger crystallite sizes. As a result of Al2O3 nanoparticle incorporation, the nanocomposites exhibited conductivity values ranging from 0.12 to 0.02 S cm−1. These engineered nanocomposite films, characterized by high crystallinity, varied electrical conductivities, and controlled band gaps, show promising potential as active components in next-generation optoelectronic devices.

Microporous Zr-metal-organic frameworks based-nanocomposites for thermoelectric applications

In the area of energy storage and conversion, Metal-Organic Frameworks (MOFs) are receiving more and more attention. They combine organic nature with long-range order and low thermal conductivity, giving them qualities to be potentially attractive for thermoelectric applications. To make the framework electrically conductive so far, thermoelectricity in this class of materials requires infiltration by outside conductive guest molecules. In this study, an in-situ polymerization of conductive polyaniline inside the porous structure of MOF-801 was conducted to synthesize PANi@MOF-801 nanocomposites for thermoelectrical applications. The growth of polyaniline chains of different loadings inside the host MOF matrix generally enhanced bulk electrical conductivity by about 6 orders of magnitude, leading to Seebeck coefficient value of -141 µVK−1 and improved thermal stability. The unusual increase in electrical conductivity was attributed to the formation of highly oriented conductive PANi chains inside the MOF pores, besides host–guest physical interaction, while the Seebeck coefficient enhancement was because of the energy filtering effect of the developed structure. Modulating the composition of PANi@MOF-801 composites by varying the aniline: MOF-801 ratio in the synthesis bath from 2:1 and 1:1 to 1:2 leads to a change in the semiconductor properties from p-type semiconductor to n-type. Among the examined composites with n-type semiconducting properties exhibited the highest ZT value, 0.015, and lowest thermal conductivity, 0.24 Wm−1 K−1. The synthesized composites have better performance than those recently reported for a similar category of thermoelectric materials related to MOF-based composites.

Highly efficient tin oxide and polyaniline-tin-oxide nanostructured materials for photocatalytic degradation of organic dyes

Herein, polyaniline-tin oxide (PANI-SnO2) nanostructured materials (NSMs) were prepared by incorporating SnO2 nanoparticles into the polyaniline (PANI) chain produced from aniline monomers. The structural, morphological, and optical features of materials were described using the scanning electron microscope (SEM), Fourier-transform infrared (FT-IR), powder X-ray diffraction (pXRD), and ultraviolet-visible (UV–Vis) spectroscopy. While a thermogravimetric analysis (TGA) was performed to assess the thermal stability of NSMs. Additionally, the as-prepared PANI-SnO2 NSMs were employed as photocatalysts to degrade several dyes, including rhodamine B (RhB), methyl orange (MO), methylene blue (MB), and methylene red (MR). The PANI-SnO2 photocatalyst showed degradation efficiencies of 84 %, 90 %, 92 %, and 60 % for RhB, MR, MO, and MB, respectively. Various factors, such as the amount of catalyst used, the amount of dye present, the effect of pH, and temperature, were also examined to determine the ideal conditions for degradation. The results showed that the photodegradation efficiency (PDE) of dyes was affected by these factors. Finally, the kinetics studies revealed that the PANI-SnO2 NSMs follow the pseudo-first-order kinetics, which makes them ideal for large-scale degradation of biological and chemical contaminants.

Fenton-mediated solar-driven photocatalysis of industrial dye effluent with polyaniline impregnated with activated TiO2-Nps

Various integrated technologies have been investigated for the remediation of heavily polluted industrial dye effluent. Also, more than 70 % of these dyes are known to be solely azo dyes used in the textile industry with 5–30 % presence in the effluent as loose dye molecules which are recalcitrant to treatment. These challenges led to the investigation of energy-efficient processes (solar) and the fabrication of high-performance nano-photocatalysts for proficient photocatalysis of dye effluent while mediating the process with Fenton reagents. The study fabricated nanopolymeric catalyst composites (P-AKT) via novel in situ coupling and impregnation of the polyaniline (PANI) with surface-activated TiO2 NPs. This fabrication is aimed at developing a high-performance catalyst with rapid and proficient photocatalytic activities to photons from sunlight irradiation. The photocatalytic process was mediated using a novel Fenton reagent to enhance the generation of radical species for dye degradation. Various instrumental characterization methods were used to study the structural, molecular, elemental, functional and optoelectronic properties of the fabricated nanocomposite photocatalysts. The result reveals functional groups aiding dye-catalyst bonding and morphological interaction reveal a surface-activated tetragonal crystalline mixture of anatase and rutile from TiO2−Nps embedded in the macromolecular chain of PANI. It also reveals the optimal conditions of 20 mg dosage, 10 mg/L initial concentration with substantial effectiveness at pH of 5 and 7. However, the most efficient photocatalyst recorded was P-AKT-2 % and P-AKT-3 % having 95 % and 94 % efficiencies at 90 min of solar irradiation. The photocatalyst equally demonstrated its capacity for effluent treatability up to 4 cycles of use.

Construction of a binder-free PANI-CQD-Cu electrode via an electrochemical method for flexible supercapacitor applications.

In recent years, flexible hybrid supercapacitors (FSCs) have played a significant role in energy storage applications owing to their superior flexibility and electrochemical properties. In this study, carbon quantum dots (CQDs) were prepared from ascorbic acid via a hydrothermal method and physical and chemical characterizations were performed. Then, the carbon quantum dots (CQDs) were doped with polyaniline (PANI) and copper (Cu) to form a PANI-CQD-Cu composite coated on carbon cloth (CC) using an electropolymerization method. In the polymerization process, CQDs bind with the PANI chain and form a PANI-CQD-Cu composite. The prepared electrode's functional group and surface morphology were characterized through XRD, Raman, BET, XPS and SEM with EDAX studies. The electrochemical properties of the PANI-CQD-Cu electrode were investigated using cyclic voltammetry, impedance spectroscopy and galvanostatic charge-discharge study. The capacitance value of PANI-CQD-Cu was 1070 mF cm-2 at 5 mA cm-2 (1070 F g-1 at 1 A g-1), which was higher than that of PANI (775 mF cm-2). Moreover, a flexible asymmetric supercapacitor (FASC) based on an activated carbon/PVA-H2SO4/PANI-CQD-Cu device was fabricated, which exhibited outstanding energy and power densities of 23.10 μW h cm-2 and 0.978 mW cm-2, respectively. The capacitance value remained at 92% after 3000 cycles. The outcome results indicated that the PANI-CQD-Cu-coated CC electrode material can be a promising electrode material for practical energy storage applications.

Undoped polyaniline-modified sawdust as an adsorbent for lead removal

Heavy metal ion adsorption employing abundant natural and agricultural wastes appears to be promising. Biodegradable sawdust is promoted as a green and sustainable alternative. In this work, potential application of sawdust has been explored for uptake of lead ions from contaminated water. Specifically, undoped polyaniline, a highly conductive polymer, was added to sawdust to improve its uptake capacity. Highest lead uptake capacity of 218 mg/g was observed at 318 K. Different surface-based characterizations for this material were performed. Morphology of prepared sawdust revealed a one-dimensional flake-like structure having a porous nature. FTIR and XRD analysis inferred successful incorporation of polyaniline into sawdust. In addition, XPS analysis revealed the importance of polyaniline chains during electrostatic adsorption of lead ions. At an adsorbent dosage of 1 g/l, optimal equilibrium conditions were reached. In accordance with Langmuir isotherm analysis, lead ion uptake was mainly driven by monolayer adsorption. As-prepared adsorbent was subjected to batch studies, where, effects of pH and interfering ions were carried out. Regeneration was also studied for four cycles.

Developing a ternary conductive hydrogel of polyacrylamide, polyaniline, and carbon nanotube: A potential chemiresistive gas sensor

Over the past few years, conductive hydrogels have received increasing attention for numerous electronic applications because of the concurrent provision of electrical conductivity, flexibility, and conformability. In the present study, a polyaniline-based conductive hydrogel was synthesized. Carbon nanotubes (CNTs) were associated with the hydrogel to impart higher electrical conductivity to the hydrogel, and ternary composites of polyacrylamide (PAM), polyaniline (PANI), and CNT were developed. To fulfill this, at first, CNT surface was decorated with carboxyl functionalities, and the carboxyl decorated CNT was included into the composition in two manners: firstly, CNTs were included during acrylamide polymerization, whereas in the second manner, CNTs were incorporated during aniline polymerization. The composite hydrogels' chemical, swelling, morphological, and electrical properties were evaluated. The experimental results corroborated that in the latter case, abundant intermolecular interactions were developed between the PANI chains and the CNT surface. Moreover, the swelling value was increased by 9% comapred to the former case. In the former case, a porous microstructure and in the latter case a fibrous microstructure was dominated. And more importantly, the electrical conductivity of the hydrogel in the latter case was 104 folds higher than that in the former case. The ternary composition prepared with the latter manner was employed for sensing the ammonia gas, and the analyses unveiled that the hydrogel represents an appropriate response in the range of 10.43%–16.87% to various concentrations of the target gas and has the potential to be a thriving chemiresistive gas sensor.

Polyaniline nanosheets templated from aniline‒acid precipitates and their electrochemical performance for flexible supercapacitor

The simple synthesis of two-dimensional (2D) polyaniline (PANI) structures remains a big challenge owing to the intrinsic growth of PANI chains into one-dimensional structures and the curling of the PANI chains into spherical particles. In this contribution, we report on the simple synthesis of PANI nanosheets by oxidizing aniline–acid precipitates with ammonium persulfate (APS) through a chemical oxidation polymerization method. The tested acids include methylene disulfonic acid, sulfuric acid, benzoic acid, oxalic acid, p-toluenesulfonic acid, hydrochloric acid, and acetic acid. The aniline–acid precipitates serve as separation-free templates for producing PANI nanosheets. The yield, oxidation level, electronic conductivity, conjugation length, and thickness of the PANI nanosheets can be tuned by controlling the molar ratio of aniline/APS. The electrochemical performance of PANI nanosheets-based symmetric supercapacitors was examined at the temperature ranging from room temperature to –60 °C. The PANI nanosheets with relatively high specific surface area rather than the oxidation level manifest superior electrochemical performance.

Structure and Conformational Properties of a Short Polyaniline Chain in a Mixture of Water and Ionic Liquid [1-Ethyl-3-methyl-imidazolium][bistriflimide] Investigated by All-Atom Molecular Dynamics Simulations.

Development of antifouling membranes for water treatment using conducting polymers and their composites is a fundamental strategy to mitigate the fouling. This manuscript presents an all-atom molecular dynamics simulations of a conducting polymer, polyaniline (PANI), immersed in an ionic liquids (ILs)-water mixtures. We have considered the ionic liquid 1-ethyl-3-methyl imidazolium bistriflimide, [EMIM]+[BIS]-. The two forms of polyaniline, emeraldine base (EB) and emeraldine salt (ES), were considered. Various intra- and intermolecular structural properties of PANI were analyzed, such as polymer chain radius of gyration Rg, radial distribution functions, and torsional angle distributions. The Rg of EB shows an increase, while the Rg of ES shows a decrease with an increase in the IL concentration. The backbone torsional angle probability distributions show a significant trans state for EB, while a combination of trans and gauche states was observed for ES. Similar supportive distributions were seen in the backbone angular distributions. Radial distribution functions between the carbon atoms at ortho and meta positions of the benzene ring on both ES and EB, as well as the amine group attached between two benzene rings, show an enhanced interaction with the ionic liquid compared to water. Anions have a dominant interaction with the polymer chain when compared to cations. The solvent accessible surface area (SASA) calculations were in accordance with the EB and ES structural properties. The SASA values are more favorable for ES than for EB. H-bond analysis shows a decrease in the number of H-bonds with water as the IL concentration increases.

Proton is Essential or Not: A Fresh Look on Pseudocapacitive Energy Storage of PANI Composites.

Protonation has been considered essential for the pseudocapacitive energy storage of polyaniline (PANI) for years, as proton doping in PANI chains not only activates electron transport pathways, but also promotes the proceeding of redox reactions. Rarely has the ability for PANI of storing energy without protonation been investigated, and it remains uncertain whether PANI has pseudocapacitive charge storage properties in an alkaline electrolyte. Here, this work first demonstrates the pseudocapacitive energy storage for PANI without protonation using a PANI/graphene composite as a model material in an alkaline electrolyte. Using in situ Raman spectroscopy coupled with electrochemical quartz crystal microbalance (EQCM) measurements, this work determines the formation of -N= group over potential on a PANI chain and demonstrates the direct contribution of OH- in the nonprotonation type of oxidation reactions. This work finds that the PANI/graphene composite in an alkaline electrolyte has excellent cycling stability with a wider operation voltage of 1V as well as a slightly higher specific capacitance than that in an acidic electrolyte. The findings provide a new perspective on pseudocapacitive energy storage of PANI-based composites, which will influence the selection of electrolytes for PANI materials and expand their application in energy storage fields.

PANI grafted onto waste poros polyurethane for co-adsorption of multiple pollutants in industrial wastewater

Simultaneously up-taking multiple pollutants from industrial wastewater is an urgent challenge in the field of adsorption technology. In this study, a polyaniline (PANI)-based adsorbent supported by waste polyurethane (PU) was designed, and its capability for simultaneous adsorption of various pollutants was investigated. The results revealed that in a simulated multi-pollutant wastewater, the adsorbent demonstrated synchronous removal efficiencies of 88% for acid red G (ARG), 40% for methylene blue (MB), 90% for Cr(VI), 58% for phosphorus (TP), 42% for NH4+-N, 30% for NO3−-N, and 63% for chemical oxygen demand (COD). The corresponding adsorption capacities were 255.81, 22.57, 105.32, 10.04, 7.98, 23.03 and 236.31 mg/gP/T, respectively. The continuous flow column adsorption lasted for 1800 min (144 columns) before reaching saturation, and no significant decrease in adsorption efficiency was observed even after 5 cycles of regeneration. X-ray photoelectron spectroscopy (XPS) and excitation-emission matrix spectroscopy (EEM) analysis revealed that ARG, Cr(VI), NO3−-N, and TP competed for the same adsorption sites, with ARG exhibiting the highest affinity, followed by Cr(VI), TP, and NO3−-N. During the adsorption process, redox reactions occurred between Cr(VI) and =N- in the PANI chain, resulting in the formation of Cr(III) and -NH+- species, which further enhanced the adsorption of anionic pollutants such as H2PO4−. The interaction between pollutants before adsorption directly affected the subsequent adsorption process. Overall, these findings demonstrate the feasibility and effectiveness of the PU-P/T adsorbent as a potential engineering adsorbent for co-adsorption of a variety of pollutants.

Long-life P-type co-doped polyaniline cathodes for ultrahigh-energy-density aqueous zinc-ion batteries

Conductive polyaniline (PANI) is considered as a promising cathode material for aqueous zinc-ion batteries (AZIBs) due to its reversible redox properties. In this study, we prepared a binder-free PANI (βPG-PANI-6) cathode co-doped with β-naphthalene sulfonic acid (β-NSA), HClO4, and graphitic acid (GA) via a layer-by-layer self-assembled electro-polymerization method. As a soft template, β-NSA micelles can be doped with HClO4 into PANI nanoparticles to prevent the tight accumulation of PANI chains. Moreover, β-NSA and GA adsorbed on the surface of PANI nanoparticles through layer-by-layer self-assembly contain abundant weak acid groups, which can act as internal proton reservoirs to offer protons to guarantee high redox activity. During the electro-polymerization process, the flexible GA matrix which forms NO bond closely with PANI can alleviate the volume expansion effect of PANI. As a result, the βPG-PANI-6 cathode can obtain superior discharge specific capacity (560.5 mAh/g, 0.2 A/g), excellent rate performance (251.3 mAh/g, 10 A/g). It is commendable that the AZIBs assembled by βPG-PANI-6 cathode deliver ultra-high energy density and power density (535.31 Wh/kg @ 187.16 W/kg, 184.45 Wh/kg @ 7378.01 W/kg). This study expands the doping chemistry of PANI and advances the development of conducting polymer for AZIBs to a new level.

Molecular Dynamics Simulation Study on Thermal Transport in Graphyne/Polyaniline Composite System

AbstractGraphyne (GY) is a new carbon material with excellent electrical conductivity and low thermal conductivity (TC). The doping of GY into polymers to improve the thermoelectric properties of the material has become a hot research trend. In this study, molecular dynamics (MD) and nonequilibrium MD are used to study the effect of the number of oxidation units of polyaniline (PANI) on TC and heat transfer of PANI and GY/PANI systems. The geometric structure of polymer, interaction energy, and heat transport of all systems are studied and analyzed. It is found that (1) as the number of oxidation units of PANI increases, the interchain and intrachain heat transfers of PANI are decreased thereby decreasing the heat transfer of the PANI chains; (2) the weak interaction energy at the interface hinders the heat flux transfer, and the phonon vibration of GY and PANI mismatch at the interfaces; eventually the above reasons lead to low interface TC; (3) the doping of GY can effectively reduce the TC of the system. This study provides some research ideas and theoretical exploration for the application of polymer doped with GY composites in the field of thermoelectricity.

A New Method to Prepare Stable Polyaniline Dispersions for Highly Loaded Cathodes of All-Polymer Li-Ion Batteries.

A new method for the preparation of polyaniline (PANI) films that have a 2D structure and can record high active mass loading (up to 30 mg cm-2) via acid-assisted polymerization in the presence of concentrated formic acid was developed. This new approach represents a simple reaction pathway that proceeds quickly at room temperature in quantitative isolated yield with the absence of any byproducts and leads to the formation of a stable suspension that can be stored for a prolonged time without sedimentation. The observed stability was explained by two factors: (a) the small size of the obtained rod-like particles (50 nm) and (b) the change of the surface of colloidal PANI particles to a positively charged form by protonation with concentrated formic acid. The films cast from the concentrated suspension were composed of amorphous PANI chains assembled into 2D structures with nanofibrillar morphology. Such PANI films demonstrated fast and efficient diffusion of the ions in liquid electrolyte and showed a pair of revisable oxidation and reduction peaks in cyclic voltammetry. Furthermore, owing to the high mass loading, specific morphology, and porosity, the synthesized polyaniline film was impregnated by a single-ion conducting polyelectrolyte-poly(LiMn-r-PEGMm) and characterized as a novel lightweight all-polymeric cathode material for solid-state Li batteries by cyclic voltammetry and electrochemical impedance spectroscopy techniques.

A Multifunctional Organic Electrolyte Additive for Aqueous Zinc Ion Batteries Based on Polyaniline Cathode.

The practical applications of aqueous zinc ion batteries are hindered by the formation of dendrites on the anode, the narrow electrochemical window of electrolyte, and the instability of the cathode. To address all these challenges simultaneously, a multi-functional electrolyte additive of 1-phenylethylamine hydrochloride (PEA) is developed for aqueous zinc ion batteries based on polyaniline (PANI) cathode. Experiments and theoretical calculations confirm that the PEA additive can regulate the solvation sheath of Zn2+ and form a protective layer on the surface of the Zn metal anode. This broadens the electrochemical stability window of the aqueous electrolyte and enables uniform deposition of Zn. On the cathode side, the Cl- anions from PEA enter the PANI chain during charge and release fewer water molecules surrounding the oxidized PANI, thus suppressing harmful side reactions. When used in a Zn||PANI battery, this cathode/anode compatible electrolyte exhibits excellent rate performance and long cycle life, making it highly attractive for practical applications.

Sponge-like, semi-interpenetrating self-sensory hydrogel for smart photothermal-responsive soft actuator with biomimetic self-diagnostic intelligence

Actuators based on hydrogels are good candidates for biomimetic soft robots due to their excellent mechanical properties and flexibility. Despite great efforts in hydrogel-based actuators, their actuation process still differs from the “recognition-judgment-execution” process that conscious intelligent beings go through owing to the lack of perceptive capacity. Herein, to imitate the intelligent actuation process of conscious organisms, a fast photo-thermal responsive and self-sensory soft actuator is proposed based on sponge-like hydrogel with semi-interpenetrating (semi-IPN) polymer network of thermosensitive poly (N-isopropylacrylamide) (PNIPAM) and electronically conductive polyaniline (PANI). The proposed actuator exhibits excellent photo-thermal responsiveness enabling remotely triggered actuation controlled by near infrared light (NIR), covering all azimuths with ultrafast response rate (within 2 s) and recover rate (within 1 s). Meanwhile, the conformational transition of PNIPAM networks during the course of actuation also lead to accompanying migration of the interpenetrated PANI chains and significant variation of local conductivity (>15%), endowing the actuator with self-sensing capacity to monitor its deformations. Eventually, a smart self-adaptive actuator is designed inspired by neuromuscular in intelligent organisms, which can actively perceive external environmental stimuli and consciously regulate its own shape transformation by monitoring and analyzing electrical signal. This sensory actuating hydrogel can provide insights into the development of artificial intelligent soft robotics with higher levels of autonomy and complexity.

Hierarchical N-doped carbon nanofiber-loaded NiCo alloy nanocrystals with enhanced methanol electrooxidation for alkaline direct methanol fuel cells

The high catalytic activity of non-precious metals in alkaline media opens a new direction for the development of alkaline direct methanol fuel cell (ADMFC) electrocatalysts. Herein, a highly dispersed N-doped carbon nanofibers (CNFs) -loaded NiCo non-precious metal alloy electrocatalyst based on metal–organic frameworks (MOFs) was prepared, which conferred excellent methanol oxidation activity and resistance to carbon monoxide (CO) poisoning through a surface electronic structure modulation strategy. The porous electrospun polyacrylonitrile (PAN) nanofibers and the P-electron conjugated structure of polyaniline chains provide fast charge transfer channels, enabling electrocatalysts with abundant active sites and efficient electron transfer. The optimized NiCo/N-CNFs@800 was tested as an anode catalyst for ADMFC single cell and exhibited a power density of 29.15 mW cm−2. Due to the fast charge transfer and mass transfer brought by its one-dimensional porous structure and the synergistic effect between NiCo alloy, NiCo/N-CNFs@800 is expected to be an economical, efficient and CO-resistant methanol oxidation reaction (MOR) electrocatalyst.