3D Polyaniline Research Articles

Nanocomposites combining 2D WS2 and 1D polyaniline for enhanced high-performance supercapacitors

The field of flexible energy storage is increasingly focusing on conductive polymers due to their inherent flexibility, high theoretical capacitance, and suitability for thin-film applications. Polyaniline stands out for its excellent capacitance and electrochemical reversibility. However, its limited cyclic stability has hindered its use in supercapacitors. To Address this, our study focuses on development of a hybrid nanocomposite that merges two-dimensional tungsten disulfide with polyaniline (WS2/PANI), that created through in-situ oxidative polymerization. Serving as an electrode material, it showcased considerable surface area and structural integrity, thanks to the electrostatic interactions and hydrogen bonds between WS2 and PANI. The nanocomposite achieved a specific capacitance of 464 Fg−1 at a current density of 10 mVs−1, displaying outstanding stability and rate capability. Moreover, we have developed all-solid-state asymmetric supercapacitors using WS2/PANI/C, activated carbon (AC/C) and Na2SO4-saturated filter paper as the positive, negative electrodes and electrolyte, respectively. The constructed device exhibited an energy density of 12.9 Whkg−1, power density of 395 Wkg−1 and retained 67 % of its initial capacitance even after 10,000 cycles. The impressive electrochemical performance of this device braces the promising future for hybrid supercapacitor technology.

Rapid Detection of Broad-Spectrum Pathogenic Bacteria Based on Highly Sensitive Proton Response of the Nucleic Acid Amplification SPQC Platform.

Pathogenic bacteria significantly contribute to elevated morbidity and mortality rates, highlighting the urgent need for early and precise detection. Currently, there is a paucity of effective broad-spectrum methods for detecting pathogenic bacteria. We have developed an innovative proton-responsive series piezoelectric quartz crystal (PR-SPQC) platform for the broad-spectrum identification of pathogenic bacteria. This was achieved by retrieving and aligning sequences from the NCBI GenBank database to identify and validate 16S rRNA oligonucleotide sequences that are signatures of pathogenic bacteria but absent in humans or fungi. The hyperbranched rolling circle amplification, activated exclusively by the screened target, exponentially generates protons that are detected by SPQC through a 2D polyaniline (PANI) film. The PR-SPQC platform demonstrates broad-spectrum capabilities in detecting pathogenic bacteria, with a detection limit of 2 CFU/mL within 90 min. Clinical testing of blood samples yielded satisfactory results. With its advantages in miniaturization, cost efficiency, and suitability for point-of-care testing, PR-SPQC has the potential to be extensively used for the rapid identification of diverse pathogenic bacteria within clinical practice and public health sectors.

Precisely Controlled Polymerization of Two-Dimensional Conducting Polymers in Quasi-Liquid Layer Enables Ultrahigh Sensing Performance.

Gas sensors based on conducting polymers offer great potential for high-performance room temperature applications due to their cost-effectiveness, high-sensitivity, and operational advantage. However, their current performance is limited by the deficiency of control in conventional polymerization methods, leading to poor crystallinity and inconsistent material properties. Here, the quasi-liquid layer (QLL) on the ice surface acts as a self-regulating nano-reactor for precise control of thermodynamics and kinetics in the polymerization, resulting in a 7.62nm thick two-dimensional (2D) polyaniline (PANI) film matching the QLL thickness. The ultra-thin film optimizes the exposure of active sites, enhancing the detection of analyte gases at low concentrations. It is validated by fabricating a chemiresistive gas sensor with the 2D PANI film, demonstrating stable room-temperature detection of ammonia down to 10 ppt in ambient air with an impressive 10% response. This achievement represents the highest sensitivity among sensors of this kind while maintaining excellent selectivity and repeatability. Moreover, the QLL-controlled polymerization strategy offers an alternative route for precise control of the polymerization process for conducting polymers, enabling the creation of advanced materials with enhanced properties.

1D/2D Heterostructured WS2@PANI Composite for Highly Sensitive, Flexible, and Room Temperature Ammonia Gas Sensor.

Flexible and room-temperature (RT) ammonia gas sensors are needed for exhaled breath detection and recognition. Two-dimensional transition metal disulfides are potential materials for RT gas sensing because of their low band gap and a large number of edge-exposed sites that can provide strong binding to gas molecules. In this work, a 1D/2D heterostructured composite material of 2D tungsten disulfide (WS2) modified with 1D polyaniline (PANI) was proposed. The fibrous PANI adsorbed on the edges and inserted in the interlayers of the laminated WS2 provide more diffusion channels for the ammonia gas and act as sensing sites. The WS2@PANI-based sensor shows high selectivity for ammonia with satisfying reproducibility and long-term stability. A response of 216.3% and a short response/recovery time of 25 s/39 s were achieved for 100 ppm ammonia gas. The sensing mechanism was investigated in detail via complex impedance spectra and in situ FT-IR, which was attributed to the synergistic effect of WS2 and PANI. The excellent sensing performance coupled with its resistance to thermal and humidity interference endows the WS2@PANI-based sensor with potential for human exhaled detection and wearable electronics.

A flexible pH sensor based on polyaniline@oily polyurethane/polypropylene spunbonded nonwoven fabric.

To fabricate a two-electrode flexible pH sensor based on polypropylene spunbonded nonwoven fabric (PP SF), oily polyurethane (OPU) was first coated on the surface of PP SF to obtain OPU/PP SF. Then, silver/silver chloride (Ag/AgCl) paste, used as the reference electrode and conductive carbon (C) paste were transferred to the OPU/PP SF surface through screen printing. Polyaniline (PANI) was deposited on the surface of the C paste to form a sensing working electrode via the electro-chemical deposition method. The results showed that the surface of the obtained PANI@OPU/PP SF flexible pH sensor (3D PANI pH sensor) presented a three-dimensional (3D) porous network structure. The 3D PANI pH sensor had good mechanical properties, an excellent Nernst response (-67.67 mV pH-1) and linearity (R2 = 0.99) in the pH range from 2.00 to 8.00 in the normal state. In the bent state, the 3D PANI pH sensor retained similar sensitivity (-68.87 mV pH-1) and linearity (R2 = 0.99). Moreover, the 3D PANI pH sensor exhibited a short response time (8 s), excellent reversibility (1.20 mV), low temperature drift (-0.0872 mV pH-1 °C-1) and long-term stability (0.83 mV h-1) in the normal state. Furthermore, the 3D PANI pH sensor can be effectively applied for pH monitoring of liquids and fruits with irregular curved surfaces. The error margin is no more than 0.16 compared to a commercial pH meter.

Barrier and passivation effects of 2D PANI@JNSs Janus nanosheets in epoxy anticorrosion coating

AbstractThe filled sheet‐like inorganic materials can usually improve the anticorrosion performance of the coating. Herein, the Janus nanosheets (JNSs) with two‐dimensional structure were prepared by phase separation method, modified by polyaniline (PANI) on the amino side of JNSs and composited with epoxy resin (EP). Scanning electron microscope (SEM), transmission electron microscopy (TEM), atomic force microscope (AFM), Fourier transform infrared spectroscopy (FT‐IR), thermogravimetry (TG) were used to characterize the morphology and chemical structure of JNSs and PANI@JNSs. The anti‐corrosion performance of coatings was measured by electrochemical impedance spectroscopy (EIS) and salt spray experiment. Compared with pure EP, the |Z|0.01Hz of 0.5%‐JNSs/EP coating and that of 0.5%‐PANI@JNSs/EP coating reached 5.6 × 108 and 5.4× 1010 Ω·cm2 after immersed for 35 days, nearly 2 and 4 orders of magnitude higher than pure EP respectively. The excellent anti‐corrosion performance of 0.5%‐PANI@JNSs/EP coating is due to the synergistic effect of physical barrier effect of PANI@JNSs, interfacial interaction between PANI@JNSs and epoxy resin and passivation effect of PANI. Moreover, PANI@JNSs possess both strengthening and toughening effects on composite coating. Janus nanosheets provide a new idea and method for preparing high‐performance anticorrosive materials.

2D polyaniline derivatives as turn-on fluorescent probe for efficient triethylamine detection at room temperature

Due to the severe toxicity of triethylamine (TEA), the preparation of chemsensors with high sensitivity, low cost and visualization for TEA detection has been a research hotspot. However, based on the fluorescence turn-on detection of TEA remains rare. In this work, three two-dimensional conjugated polymers (2D CPs) were prepared by chemical oxidation polymerization. These sensors show a quick response and excellent selectivity toward TEA at room temperature. The minimum limit of detection (LOD) for TEA was 3.6 nM in the range of 10 μM ∼ 30 μM. Interestingly, the paper sensor based on P2–HCl can quantitatively detect TEA gas within 20 s, which showed great application potential in fields of environmental monitoring. Besides, Fourier transform infrared spectra (FT-IR), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) data were used to thoroughly interpret the sensing mechanism. This work provided an effective method for the development of 2D fluorescent chemosensors for TEA detection.

Surplus charge injection enables high-cell-potential stable 2D polyaniline supercapacitors

The extraordinary pseudocapacitance of polyaniline (PANI) can be only realized in acid electrolytes with a limited potential window of 0.6∼0.8 V. As the potential further increases, PANI will suffer from the hydrolysis issue, leading to molecular-chain fracture and oxidative failure. In this work, we propose a strategy of surplus electron injection to stabilize the molecular chain of PANI at high cell potential. The surplus electron injection in 2D PANI is realized by exceeding the stable potential induced by an asymmetric supercapacitor structure design. As excessive charges are poured, supramolecular hydrogen bonds presented at 2D PANI capture them and generate additional redox reaction, which suppresses the damage of 2D PANI molecular structure and simultaneously strengthens its capacitive behavior. This effect is vividly demonstrated by the modulated electronic structure as indicated by shifting up the Fermi level, shifting down the work function and increasing the electrical conductivity. Consequently, high cell potential (1.2 V) 2D PANI supercapacitors with sulfuric acid electrolyte deliver a much longer cycling lifetime (76.8% vs. 45.1% after 10,000 cycles) and a much higher energy density (19.9 vs. 7.53 Wh kg‒1) than that of low cell potential (0.8 V) 2D PANI counterpart. This work guides to a novel way to design high cell potential aqueous-solution supercapacitors.

Flame-retardant fibre-particle-polymer semiconductive networks for physically transient supercapacitors and chemiresistors

With fast development of green economy and carbon neutral society, biodegradable and sustainable materials are urgent needed for multifunctional transient electronics. Here, a flexible, green and flame-retardant fibre-particle-polymer network is developed for physically transient supercapacitors and chemiresistors. By regulating 1D-0D-2D ternary interface, micro/nanoarchitectured polyaniline/ink/alginate semiconductive network enables effective electrolyte infiltration and abundant surface adsorption and diffusion. Moreover, the 0D ink particles promote interface bonding between 1D alginate fibres and 2D polyaniline, giving rise to better wear resistance, compression-after-impact strength and electrical conductivity. As expected, the transient supercapacitor delivers high areal capacitance of 134.1 mF cm−2, and the transient gas sensor exhibits desirable response (33 %) and long-term stability (56 days) toward 40 ppm NH3 at room temperature, which is superior to most of previous reports. This work pushes forward a significant step towards fibre-particle-polymer interfacial design of physically transient electronics and shows great potential in flexible platform based on comfortable biofibers.

Dual effects of hetero-interfaces on phonon thermal transport across graphene/C[formula omitted]N lateral superlattices

Two-dimensional (2D) lateral superlattices, a typical artificial nano-phononic crystal, have stimulated widespread interests and potential application prospects in terms of their physically interesting features. Herein, we have found wave-particle crossover of phonon transport in the graphene (Gr)/2D polyaniline (C3N) lateral superlattices, which is an indication of a transition in the phonon transport mechanism from the incoherent to coherent regime. Due to the high structural similarity of C3N to Gr, the thermal conductivity of the Gr/C3N lateral superlattice can achieve an ultra-wide modulation range of about 500∼1100 W m−1 K−1, which is far beyond that of other superlattices. The analysis shows that an increase of the interface density will on the one hand weaken the thermal conductivity by increasing phonon-interface scattering, and on the other hand increase it by lowering the phonon transport barriers and allowing more long-wavelength phonons to participate in the transport. This determines the parabolic trend of thermal conductivity containing the minimum, and also reflects the dual effects of hetero-interfaces on phonon thermal transport. In addition, phonon calculations show that the above variation in thermal conductivity is entirely attributable to differences in the phonon mean free path for different interface densities and is not related to their group velocity.

A three-dimensionally hierarchical interconnected silicon-based composite for long-cycle-life anodes towards advanced Li-ion batteries

Although the utilization of conducting polymers in silicon anodes as both a conductive agent and binder is extremely attractive, key challenges exist in maintaining constant electric connectivity with silicon, especially during long-term cycling. In addition to the in-situ formation of polyaniline (PANI) encapsulating silicon nanoparticles (SiNPs) inside, herein PANI is also used as a three-dimensional (3D) bridge to interconnect the outside carbon nanotubes functionalized with carboxyl groups (CNFs-COOH) via electrostatic attraction and π-π conjugation. Further improvements in Li-ion diffusion kinetics and cycling properties can be achieved by low-temperature sintering the double-protected SiNPs without destruction of the 3D PANI conductive skeleton. Such a novel composite (i.e. Si@C/PANI-CNT) with a 3D hierarchically interconnected architecture containing 52 wt% SiNPs delivers a high discharge capacity of 879 mAh g−1 at 0.5 A g−1 with a capacity loss of 0.084% per cycle after 500 cycles. Increasing the current density to 1 A g−1, no big change in the 500th discharge capacity (817 mAh g−1) is found and the specific capacity still stabilizes around 605 mAh g−1 over 1000 cycles.

Revealing Kinetics Process of Fast Charge‐Storage Behavior Associated with Potential in 2D Polyaniline

Clarifying the electrode kinetics and thermodynamic processes of 2D materials in electrochemical energy‐storage system becomes an important topic, especially for the system with complex and interlaced electrochemical processes. One single analytical method can hardly describe the diffusion‐controlled and interface‐reaction‐controlled process. Hence, the tungstate‐linked polyaniline, a novel 2D conductive polymer with obvious Faradaic reaction, is introduced, as the research object. Based on the multi‐scan rate cyclic voltammetry data, the applicable rules of different electrochemical kinetic treatment methods are proved effectively: the rate fitting equation based on theoretical capacitance calibration is more suitable to describe the kinetic behavior of interface‐reaction‐controlled process, while the power–law relationship based on the b value is more reasonable to study the diffusion‐controlled process. Moreover, the higher capacitance of the electrode materials in acidic electrolyte is emphasized via in situ electrochemical testing techniques. Proton intercalation and participating in the redox reaction can obviously accelerate the electrode process. The developed multidimensional assessment method is superior in more accurate analysis of the kinetics of electrochemical energy‐storage devices.

Inkjet printing of 2D polyaniline for fabricating flexible and patterned electrochromic devices

Conjugated organic polymer (COP)-based electrochromic devices (ECDs) exhibit promising applications in digital and color displays. However, fabricating COP-based ECDs integrated with excellent electrochromic performance, customized patterns, and flexibility remains challenging. In this study, we report inkjet-printed, flexible, and patterned ECDs based on two-dimensional (2D) polyaniline (PANI) sheets, which are evenly dispersed in formic acid (FA) enabling high-precision, stable inkjet printing. The pristine lamellar structure of PANI sheets, which combine nanoscale thickness and an appropriate doping ratio, and the additive-free ink composition endow the printed PANI electrodes and ECDs with high performance. The fabricated PANI electrode exhibits a high optical contrast (76% at a wavelength of 750 nm), a good coloration efficiency (CE) of 259.1 cm2 C−1, and a short coloration/bleaching time (1.8/2.4 s), simultaneously integrated with pseudocapacitance and mechanical flexibility. Moreover, the 2D lamellar PANI ink developed in this study can be printed into various designed patterns, particularly for electrochemically controlled, addressable electrochromic displays. This work highlights 2D lamellar PANI as a promising electrochromic material for flexible and patterned ECDs.

3D reactive printing of polyaniline hybrid hydrogel microlattices with large stretchability and high fatigue resistance for wearable pressure sensors

Conducting polymer hydrogels face difficulties in the combination of high elasticity, large sensitivity and wide response range for flexible pressure sensing. Herein, an intrinsically stretchable polyaniline hybrid hydrogel (PHH) is prepared through a reactive shaping method including two steps. First, a high-viscosity precursor solution containing poly(acrylic acid) (PAA), poly(ethylene oxide) (PEO) and aniline monomers is submerged into an acid solution containing initiators for the polymerization of aniline, and gelation is quickly formed due to the formation of dense hydrogen bonds between the PAA and PEO chains. Second, the initiators in the acid solution facilitate subsequent in-situ polymerization of aniline confined in the PAA/PEO framework into a 3D polyaniline (PANI) network. Benefiting from the formation of reversible hydrogen bonds and electrostatic interactions between the PAA/PEO and PANI networks, the resultant PHH exhibits large stretchability and high fatigue resistance. The reactive shaping method facilitates a 3D reactive printing of PHH into pre-designed microlattice structures with high elasticity and electron/ion dual-conducting pathways, which is promising as a stretchable conductor for capacitive pressure sensors. The sensors therefore display high sensitivity (7.10 kPa−1) in a wide detecting range and are capable of detecting complex human motions for wearable sensing applications.

Redox‐mediated proton transport of two‐dimensional polyaniline‐based nanochannels for fast capacitive performance

AbstractTwo‐dimensional (2D) materials are being increasingly exploited for ion transport and storage under nanoconfinement. Here we demonstrate distinct ion transport behavior upon potential‐induced redox reaction in 2D tungstate anion cross‐linked polyaniline (TALP) electrode. It is found that, in the neutral electrolyte, SO42− ion serves as the main charge carrier in 2D polyaniline backbone when the electrical double layer charging dominates. While in an acidic electrolyte, proton transport in TALP turns to be the dominant ion behavior that is associated with the proton‐promoting surface redox processes. Moreover, higher capacitance along with better capacitive retention at a high rate is also demonstrated for TALP electrode in acidic electrolyte compared with that in the neutral environment. The results show that 2D nanoionics can be manipulated by applying redox‐active materials to build the nanochannels that allow the regulation of surface charge and chemistry with potential‐specific redox reactions.

Fabrication of two-dimensional carbon/V2O3 composite nanosheets and their application for electrochemical sensing

Two-dimensional (2D) nanomaterials are newly developed and promising modified electrode materials for non-enzymatic hydrogen peroxide (H2O2) detection via an electrochemical strategy due to their unique nanosheet-like structure and excellent electron transport capability. In this study, 2D polyaniline nanosheets doped with vanadic acid have been fabricated and used as templates and precursors to realize the successful preparation of carbon/vanadium trioxide (C/V2O3) nanosheets, which are assembled with a large quantity of V2O3 nanoparticles with an average size of 58.3 nm on carbon matrix. The as-prepared C/V2O3 nanosheets present an excellent sensing performance toward H2O2 with a wide detection range over 5.0–1500 μM and a low detection limit of 1.7 μM (S/N = 3), which are superior to many previous reported metal oxides and even noble metals-based sensors. Furthermore, the C/V2O3 nanosheets-based sensor displays a desirable selectivity, reproducibility, and stability, offering the feasibility for H2O2 detection in real samples. This study provides an efficient way to construct 2D metal oxides and carbon-based nanomaterials for non-enzymatic electrochemical sensing applications.

A sensitive and flexible sensor enhanced by constructing graphene-based polyaniline conductive networks

A sensitive and flexible sensor with dissimilar 3D conductive networks was fabricated by coating reduced graphene oxide (RGO) and polyaniline (PANI) on warp-knitted polyester-spandex fabric. In this study, the average length of 40∼80um 1D PANI rods or 2∼10um 1D PANI nanowires combined with 2D RGO sheet, forming 3D conductive networks. First the graphene oxide (GO) sheets was coated on the surface of fabric, then the GO was reduced to RGO, and the PANI array with ordered shapes was prepared on the surface of RGO fabric by self-assembled method and using sodium dodecyl benzene sulfonate (SDBS)/hydrochloric acid (HCl) or HCl as dopants. It could be found that the obtained 3D conductive network mainly presents two morphologies, one is nanorods-sheet shape (1:90 SDBS/HCl concentration ratio), and the other is nanowires-sheet shape (HCl 1 mol/L). The results show that the fabric with 3D nanorods-sheet conductive network exhibits outstanding conductivity (resistance = 0.228 KΩ/sq), strain sensitivity, wide strain sensing range (tolerable strain up to 100 %), and repeatability (withstand 500 stretching-releasing tests), precisely detecting human motion in flexible wearable devices.

Improving the stability of Pb2+ ion-selective electrodes by using 3D polyaniline nanowire arrays as the inner solid-contact transducer

Polyaniline nanowire arrays (PANI- NWA) were synthesized by electrochemical deposition, then successfully applied as the ion-to-electron transducer in ion selective electrodes (ISEs) for the detection of aqueous Pb2+ ions. When used as the solid-contact layer in Pb2+-ISEs, the PANI- NWA delivered a high capacitance and low impedance as measured by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), respectively, thus delivering efficient ion-to-electron transfer. Owing to the open structure of the nanowire arrays, Pb2+ ions can able to easily penetrate the PANI layer, further enhancing the detection efficiency. Developed GC/PANI- NWA/Pb2+-ISE showed outstanding potentiometric performance, including a low Pb2+ detection limit (2.5 × 10−8 M), a short response time (about 1 s), high stability in N2 (or O2) and no light sensitivity. Further, the water layer between the solid-contact layer and the ISM was largely eliminated when three-dimensional PANI- NWA were applied as the solid contact layer, thus enhancing the stability of the ISE.

A Flexible Electromagnetic Interference Shielding Fabric Prepared by Construction of PANI/MXene Conductive Network via Layer‐by‐Layer Assembly

AbstractThe electromagnetic interference (EMI) shielding textiles accomplishing high‐level EMI protective performance and wear comfort has been designed and developed. 1D polyaniline nanowires and 2D transition metal carbide/carbonitride nanosheets are loaded on the carbon fiber fabric via a layer‐by‐layer (L‐b‐L) assembly approach to fabricate a functional layer and followed with a polydimethylsiloxane (PDMS) coating. The resultant fabric exhibits a high electrical conductivity of ≈325 S m−1 and the EMI shielding effectiveness ≈35.3 dB with only 0.376 mm thickness. Benefiting from the hydrophobic effect of thin PDMS film, a satisfactory self‐cleaning performance with a large contact angle of 135.2° is achieved. Furthermore, favorable flexibility, air permeability (346 mm s−1), and thermal management further broaden the field of practical application. This work can provide a new solution for next‐generation EMI shielding materials in view of the comprehensive performance.

3D Polyaniline Nanofibers Anchored on Carbon Paper for High-Performance and Light-Weight Supercapacitors.

In the field of advanced energy storage, nanostructured Polyaniline (PANI) based materials hold a special place. Extensive studies have been done on the application of PANI in supercapacitors, however, the structure–property relationship of these materials is still not understood. This paper presents a detailed characterization of the novel sodium phytate doped 3D PANI nanofibers anchored on different types of carbon paper for application in supercapacitors. An excellent relationship between the structures and properties of the synthesized samples was found. Remarkable energy storage characteristics with low values of solution, charge transfer and polarization resistance and a specific capacitance of 1106.9 ± 1.5 F g−1 and 779 ± 2.6 F g−1 at current density 0.5 and 10 Ag−1, respectively, was achieved at optimized conditions. The symmetric supercapacitor assembly showed significant enhancement in both energy density and power density. It delivered an energy density of 95 Wh kg−1 at a power of 846 W kg−1. At a high-power density of 16.9 kW kg−1, the energy density can still be kept at 13 Wh kg−1. Cyclic stability was also checked for 1000 cycles at a current density of 10 Ag−1 having excellent retention, i.e., 96%.