Conducting Polymer Films Research Articles

Love wave propagation in piezoelectric structures bonded with conductive polymer films

In this study, we investigate analytically Love wave propagation in layered piezoelectric structures, where a thin conductive polymer layer is bonded to an unbounded piezoelectric substrate. The dispersive relation is derived and the effects of viscosity and conductivity on the phase velocity and attenuation of Love wave are analyzed and discussed. The results reveal that the effects of the viscosity and conductivity on the properties of Love wave are obvious. The phase velocity is affected by the viscosity and conductivity slightly, while the attenuation is remarkably changed with the varying frequency of the waves, viscosity and conductivity, respectively. The relationship between attenuation and frequency are not monotone increasing. The analytical solutions results are well-matched with the finite element results. The results in this work is useful for the design of acoustic wave device.

Application of intrinsically conducting polymers in flexible electronics

AbstractIntrinsically conducting polymers (ICPs), such as polyacetylene, polyaniline, polypyrrole, polythiophene, and poly(3,4‐ethylenedioxythiophene) (PEDOT), can have important application in flexible electronics owing to their unique merits including high conductivity, high mechanical flexibility, low cost, and good biocompatibility. The requirements for their application in flexible electronics include high conductivity and appropriate mechanical properties. The conductivity of some ICPs can be enhanced through a postpolymerization treatment, the so‐called “secondary doping.” A conducting polymer film with high conductivity can be used as flexible electrode and even as flexible transparent electrode of optoelectronic devices. The application of ICPs as stretchable electrode requires high mechanical stretchability. The mechanical stretchability of ICPs can be improved through blending with a soft polymer or plasticization. Because of their good biocompatibility, ICPs can be modified as dry electrode for biopotential monitoring and neural interface. In addition, ICPs can be used as the active material of strain sensors for healthcare monitoring, and they can be adopted to monitor food processing, such as the fermentation, steaming, storage, and refreshing of starch‐based food because of the resistance variation caused by the food volume change. All these applications of ICPs are covered in this review article.

Fast, simple, and gentle method for removal of polythiophene and other conductive polymer films from gold electrodes

Polythiophene is a prominent conductive polymer that can easily be deposited on electrodes in thin films. Polythiophene films convince with protein repellent properties and excellent environmental stability, which makes them an ideal candidate for the construction of various sensors. However, due to the strong absorption of polythiophene onto gold, its removal is a challenging task. Therefore, we developed a new method for the fast, simple and gentle removal of polythiophene films from gold electrodes. It is based on the induction of a shear stress caused by film swelling and allows the films to be easily wiped off the electrodes after treatment. The protocol is versatile and can be applied to a series of solvents, counter ions, and other conductive polymers; it even enables the removal of polypyrrole with a solution as simple as aqueous sodium sulphate. The quality of cleaned electrodes was evaluated using electrochemical impedance spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and white light interferometry. Our protocol allowed to reuse the utilized screen-printed thick film electrodes for up to fifteen times and hopefully supports the community in their research regarding the interesting and future oriented field of conductive polymers.

Highly selective and sensitive differential pulse voltammetric method based on poly(Alizarin)/GCE for determination of cefadroxil in tablet and human urine samples

Cefadroxil, which belongs to the first-generation cephalosporin class of β-lactam antibiotics, develops bacterial resistance necessitating development of sensitive and selective method for its determination. This paper reports determination of cefadroxil in tablet and human urine samples using poly(alizarin)/GCE. CV and EIS results confirmed deposition of a conductive and electroactive polymer film. Relative to the peak of cefadroxil at the bare electrode, an irreversible oxidative peak at poly(Aliz)/GCE with four folds of current and much reduced potential verified improvement on electrode surface conductivity and effective surface area. DPV current varied linearly with concentration of cefadroxil in the range 1.0 × 10−7–1.0 × 10−4 M with LoD, and LoQ of 8.1 × 10−9, and 2.7 × 10−8 M, respectively. Detection of 99. ± 3.01 and 99.5 ± 2.03% cefadroxil of the 10.0 and 20.0 µM nominal tablet samples, respectively showed agreement between the detected amount and tablet label. Spike recovery in the range 99.5–100.5% in tablet and human urine samples and interference recovery results in the presence of selected potential interferents in tablet sample with percent error of 0.0–4.9% validated the applicability of the method for determination of cefadroxil in real samples. Compared with previously reported works on cefadroxil determination, relatively wider linear range and extremely low limit of detection of the present method along with its excellent accuracy and selectivity make the method an outstanding candidate for determination of cefadroxil in real samples.

Chemical treatment of grafted rubber‐based conductive polymer film for homogeneity improvement

AbstractConductive polymer film that possess stable electrical conductivity and good mechanical performance was prepared with the incorporation of polyaniline (PAni) and carboxymethyl cellulose (CMC) in grafted rubber (MG49) matrix was synthesized in this research study. PAni was synthesized through the chemical oxidation process while CMC was produced using the carboxymethylation reaction. Besides, conductive polymer films of MG 49/PAni/CMC were synthesized using ex‐situ polymerization. The optimum reinforcement of CMC in the polymer films was proven through UTM analysis at 8% CMC loading with tensile strength and Young Modulus of 12.1 and 630 MPa, respectively. The chemical interaction, crystallinity, thermal stability, and morphology behaviors of the conductive polymer films before and after chemical modifications were confirmed by FTIR, XRD, TGA, and SEM analyses. Chemical modification by the introduction of silane coupling agent into conductive polymer films significantly enhances the homogeneity of the composites by giving a stable and narrow range of electrical conductivity with the value of 6.931 × 10−7–8.768 × 10−7 S cm−1. As conclusion, the mechanical performance, and electrical conductivity of MG49/PAni/CMC(8%)‐TMMS is more homogenous and fulfils the requirements of conductive polymer film that can be potentially applied in the flexible conductors of stretchable electronics.

Superhydrophobic-Substrate-Assisted Construction of Free-Standing Microcavity-Patterned Conducting Polymer Films.

Patterned conducting polymer films with unique structures have promising prospects for application in various fields, such as actuation, water purification, sensing, and bioelectronics. However, their practical application is hindered because of the limitations of existing construction methods. Herein, a strategy is proposed for the superhydrophobic‐substrate‐assisted construction of free‐standing 3D microcavity‐patterned conducting polymer films (McPCPFs) at micrometer resolution. Easy‐peeling and nondestructive transfer properties are achieved through electrochemical polymerization along the solid/liquid/gas triphase interface on micropillar‐structured substrates. The effects of the wettability and geometrical parameters of the substrates on the construction of McPCPFs are systematically investigated in addition to the evolution of the epitaxial growth along the triphase interface at different polymerization times. The McPCPFs can be easily peeled from superhydrophobic surfaces using ethanol because of weak adhesion and nondestructively transferred to various substrates taking advantage of the capillarity. Furthermore, sensitive light‐driven McPCPF locomotion on organic liquid surfaces is demonstrated. Ultimately, a facile strategy for the construction of free‐standing 3D microstructure‐patterned conducting polymer films is proposed, which can improve productivity and applicability of the films in different fields and expand the application scope of superwettable interfaces.

Tunable Structural Color Images by UV-Patterned Conducting Polymer Nanofilms on Metal Surfaces.

Precise manipulation of light-matter interactions has enabled a wide variety of approaches to create bright and vivid structural colors. Techniques utilizing photonic crystals, Fabry-Pérot cavities, plasmonics, or high-refractive-index dielectric metasurfaces have been studied for applications ranging from optical coatings to reflective displays. However, complicated fabrication procedures for sub-wavelength nanostructures, limited active areas, and inherent absence of tunability of these approaches impede their further development toward flexible, large-scale, and switchable devices compatible with facile and cost-effective production. Here, a novel method is presented to generate structural color images based on monochromic conducting polymer films prepared on metallic surfaces via vapor phase polymerization and ultraviolet (UV) light patterning. Varying the UV dose enables synergistic control of both nanoscale film thickness and polymer permittivity, which generates controllable structural colors from violet to red. Together with grayscale photomasks this enables facile fabrication of high-resolution structural color images. Dynamic tuning of colored surfaces and images via electrochemical modulation of the polymer redox state is further demonstrated. The simple structure, facile fabrication, wide color gamut, and dynamic color tuning make this concept competitive for applications like multifunctional displays.

An Innovative Sensor Construction Strategy via LbL Assembly for the Detection of H2O2 Based on the Sequential In Situ Growth of Prussian Blue Nanoparticles in CMC-PANI Composite Film

Although Prussian-blue (PB) is an attractive peroxidase mimetic catalyst for hydrogen peroxide (H2O2) sensing, its utilization is challenging in composite film-based sensor systems. It loses physical integrity and electroactivity by the OH− ion released from the catalytic reactions. For this reason, extensive research efforts have been devoted to improving PB’s stability. In this work, we report an H2O2 sensing system based on carboxymethyl cellulose (CMC), polyaniline (PANI), and PB nanoparticles (PBNPs). Electrochemical polymerization of aniline in the presence of CMC provided a conductive matrix for the immobilization of PBNPs. A spontaneous and sequential in situ production strategy of PBNPs (sp-PB and sis-PB) on such a matrix was evaluated, employing a repeating layer-by-layer (LbL) assembly strategy to improve the electrochemical performance of the sensor electrode. With this technique, PBNPs have been gradually formed within the composite film by diffusion (spontaneously) and electrochemical driving force instead of being subsequently inserted into the conductive polymer film. The sensing system constructed via sis-PB provided excellent analytical performances on H2O2 sensing compared to that obtained by sp-PB. Furthermore, the LbL-assembling of the sis-PB-envisaged CMC:PANI matrix as a catalyst-polymer 3D-hybrid framework has proven effective in developing PBNPs-based electrochemical sensors used for the detection of H2O2 in tap water.

Electrogenerated chemiluminescence of luminol on wireless conducting polymer films

We report on the generation of electrochemiluminescence (ECL) from luminol and hydrogen peroxide (H2O2) in alkaline aqueous solution on entirely pure conducting polymer (CP) films. Poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy) films prepared by constant current electrolysis were used as bipolar electrodes (BPEs) to drive ECL emission in a wireless mode with the aid of bipolar electrochemistry. A common digital camera was used to capture the strong ECL emission of luminol generated at the anodic pole of such films. ECL intensity profiles revealed a gradient emission on both materials, with a broad light-emitting region on PPy and a narrow, edge-confined, ECL region on PEDOT. Imaging analysis also allowed the evaluation of the ECL behavior of both CPs as a function of the total applied voltage (Etot) and conductivity. Furthermore, electric-field driven generation of molecular O2 induces propulsion of PEDOT and PPy films that can be followed by luminol ECL. In our knowledge, such result represents the first example of light-emitting electrochemical swimmers based on free-standing films of intrinsically pure CPs. We presume that our findings can both foster the use of such materials in the wide fields of ECL and bipolar electrochemistry and open up to their application as organic light-emitting electrochemical swimmers.

Novel Data Science Driven Chemical Agent Sensors: Towards Better Discrimination in Complex Environments

Chemical agents remain a persistent threat to both Warfighters and civilian personnel in both combat and non-combat environments. While many useful detection technologies exist to provide early warning, many of them suffer from similar drawbacks. Most common are unacceptable false positive response rates and inability to discriminate target analytes in complex or obscurant-laden environments. A typical approach to this problem is to develop material solutions for more specific and sensitive sensors. While useful, these solutions are often too expensive, not practical, or non-deployable. Our approach fuses both material and data science to extend the power of multiplexed sensor arrays towards more accurate and faster detection and discrimination.This presentation will discuss our approach towards vapor analyte detection using multiplex array systems combined with novel data science approaches. For vapor phase detection, sorptive and conductive graphene-based nanocomposite polymer films as well as select 2D conductive materials are used for semi-selective affinity towards chemical agent simulants in binary mixtures with common obscurants. Response data are pre-processed using a novel algorithm called the Variational Autoencoder Kalman Filter and the entire response dataset is used to train neural networks for analyte discrimination. To inform the neural networks to facilitate accurate and fast analyte discrimination, datasets far exceeding the capability of laboratory measurements are needed. Here too we describe our approach to generate simulated data to supplement and augment the classification algorithm machine learning process. We lastly demonstrate this approach to discriminate binary and tertiary mixtures of analytes with both similar and different chemical similarity both in and out of the precise of common environmental interferents.

(Invited) Flexible, Stretchable and Healable Electronics

Organic electronics, based on semiconducting and conducting polymers, have been extensively investigated in the past decades and have found commercial applications in lighting panels, smartphone and TV screens using OLEDs (organic light emitting diodes) technology. Many other applications are foreseen to reach the commercial maturity in future in areas such as transistors, sensors and photovoltaics.Organic electronic devices, apart from consumer applications, are paving the path for key applications at the interface between electronics and biology, such as in polymer electrodes for recording and stimulating neural activity in neurological diseases. In such applications, organic polymers are very attractive candidates due to their distinct property of mixed conduction: the ability to transport both electron/holes and ionic species. Additionally, conducting polymers offer the possibility to tune their surface properties (e.g., wettability or chemical reactivity) by changing their oxidation state, thus promoting or hindering the adhesion of biomolecules. This feature can be particularly useful for enhancing the biocompatibility of implantable electrodes.My talk will deal with processing and characterization of conducting polymer films and devices for flexible, stretchable and healable electronics.Self-healing electronic materials are highly relevant for application in biology and sustainable electronics. We observed mechanical and electrical healability of PEDOT:PSS thin films. Upon reaching a certain thickness (about 1 µm), PEDOT:PSS thin films damaged with a sharp blade can be healed by simply wetting the damaged area with water. The process is rapid, with a response time on the order of 150 ms. Significantly, by blending with other polymers, the films are transformed into autonomic self-healing materials without the need of external stimulation. This reveals a new property of PEDOT:PSS and enables its immediate use in flexible and biocompatible electronics, such as electronic skin and bio-implanted electronics, placing conducting polymers on the front line for healing applications in bioelectronics.

(Invited) Ligand-Functionalised Conducting Polymer Films for Analysis of Metal Ions in Solution

Innumerable technological devices and applications utilise metals and metal ions that ultimately find their way into the environment. While many metals are required at trace level for good health, their presence at higher levels is generally detrimental to human health and to the environment at large. For example, higher levels of copper are associated with liver and kidney disease; of nickel with cancer, cardiovascular disease, neurological conditions and infant developmental disorders; and of cobalt with respiratory conditions. This motivates the need to detect and determine these species at trace level; a related goal (not addressed directly here) is their extraction for the purposes of remediation. Although numerous analytical techniques exist for the determination of metal ions, electrochemically-based devices have a number of advantages, including portability for remote application. This work explores underpinning fundamental electrochemistry and interfacial characterisation associated with the fabrication and performance of carboxylate ligand-functionalised conducting polymer films as metal ion sensing moieties immobilised on electrode surfaces.Typical chelating ligands for metal ions are relatively bulky compared to the electropolymerizable monomer units, for example based on pyrrole or thiophene, commonly used to generate electroactive polymer films. As a consequence, electropolymerization of ligand-functionalised monomers is not generally effective: steric hindrance simply impedes coupling of the monomer units. We therefore adopt the alternative approach of electropolymerizing monomers functionalised with relatively small labile groups, followed by hydrolysis of the labile groups and re-functionalisation with the desired ligand. Here we explore this strategy for pyrrole-, thiophene- and aniline-based monomers functionalised with 9-fluorenylmethoxycarbonyl (fmoc) or pentafluorophenyl groups via ester linkages. Following electrochemically controlled polymerization, the resulting polymer films were treated with base to remove the labile groups, then with Nα,Nα-bis-(carboxymethyl)-L-lysine to couple N-nitrilotriacetic acid functionalities via amide formation.The polymerization process and the subsequent electroactivity of each of the parent films were studied using voltammetric and nanogravimetric (QCM) techniques. The ultimate effectiveness of the surface synthetic sequence, effected by post-deposition functionalisation with the ligand species, was validated using FTIR spectroscopy. This was accomplished by monitoring the bands associated with the carbonyl functionality: this is initially part of an ester, then an acid and finally an amide, each of which has a characteristic frequency. In the case of initially pentafluorophenyl-functionalised monomers, the hydrolysis of this group is associated with the loss of the C-F functionality. Measurements as a function of time permit the dynamics of these processes to be followed. Additionally, nanogravimetric measurements allow the time course of as-deposited polymer hydrolysis and subsequent functionalisation to be followed and quantitatively compared with the reaction stoichiometry.The effectiveness of these ligand-functionalised films was explored in terms of their ability to take up nickel, cobalt and copper ions from aqueous solution. Coulometric and gravimetric (QCM) data at various points in the process and as a function of solution metal ion concentration permit the acquisition of isotherms for metal ion uptake. At high metal ion concentration, the ligand sites are saturated; this permits metal:ligand stoichiometry to be evaluated. The relative merits of Langmuir, Frumkin, Temkin and Freundlich isotherms are discussed and the viability of the films for metal ion sensing evaluated. Unsurprisingly, the Langmuir isotherm provides a relatively poor description of the variation of metal ion uptake with concentration; this is attributed to the rather simplistic assumptions of this model. Of the remaining models, the Frumkin isotherm provides the best description of metal ion uptake for all systems considered. The binding constants evaluated from the polymer isotherms are significantly smaller than for the same ligand in solution; this is presumably a consequence of steric effects in the surface-confined polymer environment. Of relevance to potential applications, the films can be regenerated, i.e. restored to metal-free state, by exposure to EDTA solution.

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

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

Design and synthesis of novel electroactive 2,2′:5′,2″-terthiophene monomers including oxyethylene chains for solid-state flexible energy storage applications

Here, we present the synthesis of novel poly(2,2′:5′,2″-terthiophene) derivatives containing oxyethylene pendant groups for the fabrication of high performance flexible redox-active electrode materials. The poly(3′,4′-bis(2-methoxyethoxy)-2,2′:5′,2″-terthiophene) (PSEDEN1), poly(3′,4′-bis(2-(2-methoxyethoxy)ethoxy)-2,2′:5′,2″-terthiophene) (PSEDEN2) and poly(3′,4′-bis(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)-2,2′:5′,2″-terthiophene) (PSEDEN3) have been electrochemically polymerized on flexible stainless steel substrates without any binder and directly employed as redox-active materials. The effect of pendant group chain length on morphological characteristics of conducting polymer films have been systematically evaluated and correlated to the charge storage properties of redox-active electrode materials. Capacitive performance tests reveal that PSEDEN1, PSEDEN2 and PSEDEN3 could reach up to specific capacitances of 135 F g−1, 212.8 F g−1 and 403.3 F g−1, respectively, at constant current density of 2.5 mA cm−2 in the potential range of 0.4–1.8 V with good rate capability performances. In addition, symmetrical flexible solid-state supercapacitor devices based on polymer gel electrolyte have also been assembled using PSEDEN1, PSEDEN2 and PSEDEN3 coated flexible stainless steel substrates and tested by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy techniques in detail. Fabricated devices (Cell 1, Cell 2 and Cell 3) have delivered maximum specific capacitances of Cspec= 29.3 F g−1, 92.1 F g−1 and 162.4 F g−1, energy densities of SE= 6.35 W h kg−1, 22.9 W h kg−1 and 41.1 W h kg−1 and power densities of SP= 929 W kg−1, 937.7 W kg−1 and 986.4 W kg−1 at a current density of 2.5 mA cm−2 in two-electrode cell configuration. Furthermore, flexible supercapacitor devices have achieved high cycle life performances with good capacitance retention values of 80.2%, 84.7% and 91.4% over 10 000 consecutive galvanic charge/discharge cycles at 2.5 mA cm−2 constant current density from 0.4 to 1.8 V. Similarly, excellent mechanical stabilities have also been observed with 3.4%, 4.66% and 1.97% capacitance losses under various bending conditions from 0° to 170° for all flexible supercapacitor devices. These results confirm that PSEDEN1, PSEDEN2 and PSEDEN3 redox-active materials with gratifying capacitive performances and excellent flexibilities have a great potential for utilization in innovative flexible or wearable energy storage solutions.Keywords

Investigation of electrochemical oxidative coupling of 3 and 6 substituted carbazoles

• Investigation of carbazole reactivity and electropolymerization mechanism. • Combination of fast electrochemistry experiments and molecular orbital calculations. • Investigation of the stability of radical cations and polarons formed by electro-oxidation of carbazoles. • Comparison of the stability of the dimers depending on the coupling positions. In this study, electrochemical behavior of different functionalized carbazoles has been studied through classical cyclic voltammetry, computational calculations, electrochemical simulations and more originally fast cyclic voltammetry. Indeed, fast electrochemistry is rarely used to study reactivity of such compounds even if it can bring very interesting information as shown in this work. Carbazoles were substituted with ethyl, tert -butyl and phenyl groups at 3 and 6 positions. Oxidation of 3-ethylcarbazole leads to very fast dimerization of formed radical cations (k dim = 1.5.10 7 M −1 .s −1 ) and electrochemical polymerization of this compound leads to a thick adherent conducting polymer film. This was also the case for 3-phenylcarbazole and 3,6-diphenylcarbazole when potential was brought over 1.7 V/SCE because of formation of very reactive radicals after oxidation process involving phenyl groups. For 3,6-diethylcarbazole, 3- tert -butylcarbazole, 3,6-ditert-butylcarbazole, as well as 3-phenylcarbazole and 3,6-diphenylcarbazole when potential is kept under 1.4 V/SCE, dimerization of radical cations is slower (k dim ≤ 1.5.10 6 M −1 .s −1 ) and no efficient electropolymerization occurs. A theoretical study of the same substituted carbazoles in their neutral and oxidized states was done using molecular orbital calculations (DFT method) to obtain additional information about carbazole reactivity. These numerical calculations were in perfect accordance with results of fast electrochemistry and electrochemical simulations regarding stability of radical cations. They demonstrated that monosubstituted carbazole dimers are probably obtained through 6-6′ coupling while 1-1′ coupling is the most favorable for disubstituted carbazole dimers.

Non-Enzymatic Glucose Biosensor Based on Highly Pure TiO2 Nanoparticles.

This study proposes a non-enzymatic glucose sensor fabricated by synthesizing high-purity TiO2 nanoparticles in thermal plasma and depositing it directly on a substrate and then depositing chitosan–polypyrrole (CS-PPy) conductive polymer films by electrochemical method. The structural properties of the deposited TiO2 nanoparticles were analyzed by X-ray diffraction (XRD) and dynamic light scattering (DLS) system. The chemical composition and structural properties of the TiO2 nanoparticle layer and the conductive polymer films were confirmed by X-ray photoelectron spectroscopy (XPS) spectra and scanning electron microscope (SEM). The glucose detection characteristics of the fabricated biosensor were determined by cyclic voltammetry (CV). CS-PPy/TiO2 biosensor showed high sensitivity of 302.0 µA mM−1 cm−2 (R2 = 0.9957) and low detection limit of 6.7 μM. The easily manufactured CS-PPy/TiO2 biosensor showed excellent selectivity and reactivity.

Mechanically stable solution-processed transparent conductive electrodes for optoelectronic applications

The bilayer structure of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) coating on silver nanowires (AgNWs) film is a promising structure for replacing indium tin oxide (ITO) as a flexible transparent conductive electrode. Pristine PEDOT:PSS film due to its hydrophilicity and high permeability cannot fully protect AgNWs from mechanical stress and oxidation. Here, we present a composite approach that improves mechanical properties and lifespan of the AgNWs/PEDOT:PSS electrode by adding polyvinyl alcohol (PVA) as a polymer-surfactant. It is shown that addition of PVA improves the conductivity as well as the stability of hybrid electrode under demanding mechanical stress conditions. The drop in conductivity of the hybrid electrode is only 17% after 2000 repeated bending cycles whereas the reference electrode has shown a dramatic drop of 180% in the conductivity. We speculate that generation of hydrogen bonds between PEDOT:PSS and PVA increases adhesivity and cohesivity of the conductive polymer film to the sublayer. So PEDOT:PSS-PVA film not only fixes the arrangement of AgNWs but also improves the welding on cross junction points. By addition of PVA, optoelectronic performance (Figure-of-merit (ΦTC)) of the electrode is improved from ΦTC = 2.646 × 10-3 Ω-1 for AgNWs/PEDOT:PSS to ΦTC = 3.819 × 10-3 Ω-1 for AgNWs/PEDOT:PSS-PVA electrode and power conversion efficiency (PCE) of the polymer solar cell (PSC) is increased by over 17%.

Second-order hyperpolarizability and nonlinear optical properties of novel organic compound-doped poly (O-methoxyaniline) polymer film

The structural characterization of a new organic compound (3, 5-bis (4-chlorophenyl)-4,5-dihydro-1H-Pyrazole) was analyzed experimentally by 1HNMR and FTIR spectroscopic technique. The analysis of HOMO–LUMO and natural bond orbital are investigated to study the charge transfer interactions leading to the properties of nonlinear behavior. Linear optical properties of a new organic compound/Poly (O- Methoxyaniline) (POMA) film were studied using Wemble and Didomenico (WD) technique to estimate the refractive index n and other optical constants such as the oscillation energy E0, the dispersion energy Ed, and the lattice dielectric constant $$\varepsilon_{\infty }$$ . Measurements of the thermally induced optical nonlinearity of novel organic compound (3, 5-bis (4-chlorophenyl)-4, 5-dihydro-1H- Pyrazole) in an organic solvent (N-methyl-2-pyrrolidone) NMP)) were studied through an excitation source (continuous-wave diode laser at the wavelength of 473 nm) in the case of the solution and a conducting polymer film. The Z-scan technique was used to measure the nonlinear refractive index( $$n_{2}$$ ) to obtain the optical response of the prepared material. The prepared sample illustrated negative and large $$n_{2}$$ values in the order of 10−7 cm2/W and reverse saturable absorption(RSA) with large values of the nonlinear absorption coefficient in the order of 10−3 cm/W. The nonlinear refractive index was determined and varied as a response to different concentrations. The determination of the figure of merit (W) and nonlinear coefficients indicate that the compound is a promising candidate for applications in the nonlinear optics field.

All-aerosol-jet-printed highly sensitive and selective polyaniline-based ammonia sensors: a route toward low-cost, low-power gas detection

We report the design and scalable fabrication of a low-cost and low-power polyaniline-based (PANI) ammonia (NH3) gas sensor on polyimide (PI) substrates using additive manufacturing techniques. The silver interdigitated electrode (IDE) arrays and conducting polymer films are printed onto PI using a direct-write technology of aerosol-jet printing. Morphological characteristics are examined by scanning electron microscopy and energy-dispersive X-ray analysis which reveal homogeneously printed PANI film on the IDE platform. The gas sensing performance is evaluated in the analytical early leak detection range of 5–1000 ppm NH3 in air as a function of both thermal (23 °C, 50 °C, 80 °C) and relative humidity (RH = 0%, 30%, 50%) exposures. The sensor exhibits sensitivity down to 5 ppm NH3 with a sub-ppm detection limit and good repeatability. We observe rapid NH3 detection at 0% RH with very extended times for equilibration and recovery. However, at both 30 and 50% RH, the room temperature response and recovery times are reduced to only about 1 min and 5 min, respectively. Experiments also reveal good sensitivity toward the analyte even at higher operating temperatures. Present results merit the practical application of aerosol-jet-printed, low-power sensors for industrial applications where low-level hazardous gas detection is essential.

Development of grafted rubber/polyaniline/carboxymethyl cellulose film as green conductive polymer film

Conducting polymer film has been found to be good alternative for conventional metal film in the application of flexible conductors for stretchable electronics. This research aims to produce green conductive polymer film with good mechanical and electrical performance through incorporation of polyaniline (PAni) as conductive material and carboxymethyl cellulose (CMC) as natural reinforcing filler in grafted rubber host. Different molar ratios of aniline (Ani) monomer and docusate sodium salt purum (AOT) dopant were used to produce PAni:AOT of molar ratio 5:3, 5:5 and 5:7. Grafted rubber/PAni/CMC films were synthesised using ex situ polymerisation and characterized by FTIR, XRD and SEM analyses. The mechanical and electrical performances were studied via universal tensile machine and resistivity meter, respectively. Incorporation of PAni in polymer films improved the electrical conductivity from 0 S cm−1 (MG49/CMC) to 1.388 $$\times$$ 10–7–1.807 $$\times$$ 10–2 S cm−1 (MG49/PAni/CMC). Addition of CMC enhanced the mechanical performances of the films with improved tensile strength and Young modulus from 8.0 (MG49/PAni 5:7) to 9.2–12.1 MPa (MG49/PAni 5:7/CMC) and 279 MPa (MG49/PAni 5:7) to 401–630 MPa (MG49/PAni 5:7/CMC), respectively. In conclusion, mechanical performance and electrical conductivity range of the synthesized conductive polymer film of MG49/PAni 5:7/CMC fulfil the recommended mechanical and electrical performance range of traditional and commercial conductive films.