Chemical deposition of conducting polymers

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.

Electrochemical and Electrical Biosensors for Wearable and Implantable Electronics Based on Conducting Polymers and Carbon-Based Materials

Bioelectronic devices are designed to translate biological information into electrical signals and vice versa, thereby bridging the gap between the living biological world and electronic systems. Among different types of bioelectronics devices, wearable and implantable biosensors are particularly important as they offer access to the physiological and biochemical activities of tissues and organs, which is significant in diagnosing and researching various medical conditions. Organic conducting and semiconducting materials, including conducting polymers (CPs) and graphene and carbon nanotubes (CNTs), are some of the most promising candidates for wearable and implantable biosensors. Their unique electrical, electrochemical, and mechanical properties bring new possibilities to bioelectronics that could not be realized by utilizing metals- or silicon-based analogues. The use of organic- and carbon-based conductors in the development of wearable and implantable biosensors has emerged as a rapidly growing research field, with remarkable progress being made in recent years. The use of such materials addresses the issue of mismatched properties between biological tissues and electronic devices, as well as the improvement in the accuracy and fidelity of the transferred information. In this review, we highlight the most recent advances in this field and provide insights into organic and carbon-based (semi)conducting materials' properties and relate these to their applications in wearable/implantable biosensors. We also provide a perspective on the promising potential and exciting future developments of wearable/implantable biosensors.

A hyperthermia-enhanced nanocatalyst based on asymmetric Au@polypyrrole for synergistic cancer Fenton/photothermal therapy

The specific tumor microenvironment is a conducive breeding ground for malignant tumors, favoring their survival, rapid proliferation, and metastasis, which is also an inevitable obstacle to tumor treatment, particularly for catalytic therapy. To address this issue, a hyperthermia-enhanced nanocatalyst (AuP@MnO2) consisting of an asymmetric Au@polypyrrole core and a MnO2 shell is constructed for synergistic cancer Fenton/photothermal therapy. In an ultra-short reaction time (15 min), the innovative introduction of a new oxidizer, tetrachloroauric acid trihydrate, not only successfully initiates the oxidative polymerization of pyrrole monomer while reducing itself to cubic Au, but also accelerates the polymerization process by supplying protic acid. After MnO2 coating, AuP@MnO2 catalyzes the conversion of antioxidant GSH and excess H2O2 into GSSG and ˙OH through Mn2+/Mn4+ ion couples, leading to oxidative damage of tumor cells. More importantly, after 1064 nm laser irradiation, more extreme oxidative imbalance and cell death are demonstrated in this work under the combined effect of photothermal and catalytic therapy, with insignificant toxicity to normal cells. This work develops an efficient one-step synthesis method of asymmetric Au@polypyrrole and provides constructive insight into its oxidative stress-based antitumor treatment.

Conductive Textiles for Signal Sensing and Technical Applications

Conductive textiles have found notable applications as electrodes and sensors capable of detecting biosignals like the electrocardiogram (ECG), electrogastrogram (EGG), electroencephalogram (EEG), and electromyogram (EMG), etc; other applications include electromagnetic shielding, supercapacitors, and soft robotics. There are several classes of materials that impart conductivity, including polymers, metals, and non-metals. The most significant materials are Polypyrrole (PPy), Polyaniline (PANI), Poly(3,4-ethylenedioxythiophene) (PEDOT), carbon, and metallic nanoparticles. The processes of making conductive textiles include various deposition methods, polymerization, coating, and printing. The parameters, such as conductivity and electromagnetic shielding, are prerequisites that set the benchmark for the performance of conductive textile materials. This review paper focuses on the raw materials that are used for conductive textiles, various approaches that impart conductivity, the fabrication of conductive materials, testing methods of electrical parameters, and key technical applications, challenges, and future potential.

Surface-Modified Polypyrrole-Coated PLCL and PLGA Nerve Guide Conduits Fabricated by 3D Printing and Electrospinning

The efficiency of nerve guide conduits (NGCs) in repairing peripheral nerve injury is not high enough yet to be a substitute for autografts and is still insufficient for clinical use. To improve this efficiency, 3D electrospun scaffolds (3D/E) of poly(l-lactide-co-ε-caprolactone) (PLCL) and poly(l-lactide-co-glycolide) (PLGA) were designed and fabricated by the combination of 3D printing and electrospinning techniques, resulting in an ideal porous architecture for NGCs. Polypyrrole (PPy) was deposited on PLCL and PLGA scaffolds to enhance biocompatibility for nerve recovery. The designed pore architecture of these "PLCL-3D/E" and "PLGA-3D/E" scaffolds exhibited a combination of nano- and microscale structures. The mean pore size of PLCL-3D/E and PLGA-3D/E scaffolds were 289 ± 79 and 287 ± 95 nm, respectively, which meets the required pore size for NGCs. Furthermore, the addition of PPy on the surfaces of both PLCL-3D/E (PLCL-3D/E/PPy) and PLGA-3D/E (PLGA-3D/E/PPy) led to an increase in their hydrophilicity, conductivity, and noncytotoxicity compared to noncoated PPy scaffolds. Both PLCL-3D/E/PPy and PLGA-3D/E/PPy showed conductivity maintained at 12.40 ± 0.12 and 10.50 ± 0.08 Scm^-1 for up to 15 and 9 weeks, respectively, which are adequate for the electroconduction of neuron cells. Notably, the PLGA-3D/E/PPy scaffold showed superior cytocompatibility when compared with PLCL-3D/E/PPy, as evident via the viability assay, proliferation, and attachment of L929 and SC cells. Furthermore, analysis of cell health through membrane leakage and apoptotic indices showed that the 3D/E/PPy scaffolds displayed significant decreases in membrane leakage and reductions in necrotic tissue. Our finding suggests that these 3D/E/PPy scaffolds have a favorable design architecture and biocompatibility with potential for use in peripheral nerve regeneration applications.

Overview of the Influence of Silver, Gold, and Titanium Nanoparticles on the Physical Properties of PEDOT:PSS-Coated Cotton Fabrics

Metallic nanoparticles have been of interest to scientists, and they are now widely used in biomedical and engineering applications. The importance, categorization, and characterization of silver nanoparticles, gold nanoparticles, and titanium nanoparticles have been discussed. Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) is the most practical and reliable conductive polymer used in the manufacturing of conductive textiles. The effects of metallic nanoparticles on the performance of PEDOT:PSS thin films are discussed. The results indicated that the properties of PEDOT:PSS significantly depended on the synthesis technique, doping, post-treatment, and composite material. Further, electronic textiles known as smart textiles have recently gained popularity, and they offer a wide range of applications. This review provides an overview of the effects of nanoparticles on the physical properties of PEDOT:PSS-coated cotton fabrics.

Nanobioremediation: A sustainable approach for the removal of toxic pollutants from the environment

In recent years, the proportion of organic and inorganic contaminants has increased rapidly due to growing human interference and represents a threat to ecosystems. The removal of these toxic pollutants from the environment is a difficult task. Physical, chemical and biological methods are implemented for the degradation of toxic pollutants from the environment. Among existing technologies, bioremediation in combination with nanotechnology is the most promising and cost-effective method for the removal of pollutants. Numerous studies have shown that exceptional characteristics of nanomaterials such as improved catalysis and adsorption properties as well as high reactivity have been subjects of great interest. There is an emerging trend of employing bacterial, fungal and algal cultures and their components, extracts or biomolecules as catalysts for the sustainable production of nanomaterials. They can serve as facilitators in the bioremediation of toxic compounds by immobilizing or inducing the synthesis of remediating microbial enzymes. Understanding the association between microorganisms, contaminants and nanoparticles (NPs) is of crucial importance. In this review, we focus on the removal of toxic pollutants using the cumulative effects of nanoparticles with microbial technology and their applications in different domains. Besides, we discuss how this novel nanobioremediation technique is significant and contributes towards sustainability.

Polyimide-Sputtered and Polymerized Films with Ultrahigh Moisture Sensitivity for Respiratory Monitoring and Contactless Sensing

Respiratory monitoring and contactless sensing using the moisture produced by respiration and perspiration have garnered considerable attention in recent years. In this study, we fabricated polyimide-sputtered and polymerized (PSP) humidity sensors with ultrahigh capacitive sensitivity, fast response, and a wide working range of relative humidity (RH). The sensors produced >40 000 times increment in the sensing signal over the 10-95% RH range at 10 Hz and exhibited good performance at low RH levels (<40%) as well. These sensors displayed excellent sensing properties with small hysteresis, long-time stability, and fast response and recovery times (2.4 and 1.2 s, respectively). In the mechanism study of PSP humidity sensors, we found that the high sensitivity can be attributed to massive hydrophilic functional groups formed on the polymer chains by moist aging with oxidation and the fast response speed is due to the mesoporous structure of PSP films. We also fabricated a 5 × 5 array of PSP humidity sensors to identify the shapes of wet objects and of leaves during transpiration. Thus, we reported a novel and effective method for fabricating high-performance humidity polymer films, channeling new pathways for the development of advanced humidity and gas sensors.

Insights into enhanced electrokinetic remediation of copper-contaminated soil using a novel conductive membrane based on nanoparticles

Electrokinetic remediation is a process in which a direct electric current is applied across a section of contaminated soil to remove metals. To improve the electrokinetic remediation in this study, a conductive membrane was fabricated via in situ chemical polymerization employing pyrrole and copper oxide nanoparticles. The fabricated membrane was placed in an electric field as part of the electrode structure. A physical model was constructed and filled with copper-contaminated kaolinite in the concentration of 200 mg/kg. To control the pH, 0.1 M citric acid and 0.01 M potassium chloride were used as the electrolyte solutions. Experimental parameters such as voltage, current, pH, EC, drained flow, and copper concentration were measured. The results showed that the minimum surface resistivity of the fabricated membrane under a maximum pressure of 8.2 kPa was 2.55 kΩ/m². The experimental results demonstrated that the use of citric acid as an electrolyte was more useful to desorb the copper due to the formation of the copper-citrate complex. When employing the fabricated membrane, the copper removal increased from 13% (in CT-2) to 63% (in GM-2), while the removal of copper using potassium chloride electrolyte increased from 42% (in CT-1) to 52% (in GM-1). The highest power consumption was obtained in experiments using citric acid. Due to the higher removal efficiency of copper in GM-2, the energy utilization efficiency (β) increased and reached 29.9 near β value of GM-1 with the lowest power consumption.

High Crystalline Quality Conductive Polypyrrole Film Prepared by Interface Chemical Oxidation Polymerization Method

The authors report that polypyrrole (PPy) films with large area and high crystalline quality have been achieved using an interfacial chemical oxidation method. By dissolving different reactants in two immiscible solvents, the PPy is synthetized at the interface region of the two solutions. The PPy films have sharp XRD diffraction peaks, indicating that the molecular chains in the film are arranged in a high degree of order and that they reflect high crystalline quality. High crystal quality is also conducive to improving electrical conductivity. The conductivity of the as prepared PPy film is about 0.3 S/cm, and the carrier mobility is about 5 cm2/(Vs). In addition, the biggest advantage of this method is that the prepared PPy film has a large area and is easy to transfer to other substrates. This will confidently broaden the application of PPy in the future.

Intrinsically conductive polymers hybrid bilayer films for the fluorescence molecular diagnosis of the Zika virus

In 2016, the Zika virus (ZIKV) infection became a major public health problem, after the discovery that an alarming increase in the number of Brazilian newborns with microcephaly could be associated with the occurrence of this viral disease during the pregnancy of their mothers. The urgent need for simple diagnostic methods that allow rapid screening of suspected cases has stimulated the search for low-cost devices capable of detecting specific sequences of nucleic acids. The present work describes the development of nanostructured films formed by bilayers of conjugated polymers for rapid detection of the presence of Zika virus DNA, via fluorescence methods. For this, we initially deposited alternating layers of polyaniline (PANI) and polypyrrole (PPY) on the surface of polyethylene terephthalate (PET) sheets. The films obtained were then characterized by SEM, UV-Vis, ATR-FTIR, and contact angle measurements. For their use as quenchers for the diagnosis of Zika, a single DNA strand-specific for ZIKV was labeled with a fluorophore (FAM-ssDNA). We determined the time required for the saturation of the interaction between probe FAM-ssDNA and the film (180 min) and the time for the maximal hybridization between FAM-ssDNA and target DNA to occur (60 min). The detection limits were estimated as 345 pM and 278 pM for the PET/PPY-PANI and PET/PANI-PPY hybrid films, respectively. The simplicity of the procedure, coupled with the fact that a positive/negative response can be obtained in less than 60 min, suggests that the proposal of using these polymeric bilayer films is a promising methodology for the development of rapid molecular diagnostic tests.

Controllable Frontal Polymerization and Spontaneous Patterning Enabled by Phase-Changing Particles

Frontal polymerization provides a rapid, economic, and environmentally friendly methodology to manufacture thermoset polymers and composites. Despite its efficiency and reduced environmental impact, the manufacturing method is underutilized due to the limited fundamental understanding of its dynamic control. This work reports the control and patterning of the front propagation in a dicyclopentadiene resin by immersion of phase-changing polycaprolactone particles. Predictive and designed patterning is enabled by multiphysical numerical analyses, which reveal that the interplay between endothermic phase transition, exothermic chemical reaction, and heat exchange govern the temperature, velocity, and propagation path of the front via two different interaction regimes. To pattern the front, one can vary the size and spacing between the particles and increase the number of propagating fronts, resulting in tunable physical patterns formed due to front separation and merging near the particles. Both single- and double-frontal polymerization experiments in an open mold are performed. The results confirm the front-particle interaction mechanisms and the shapes of the patterns explored numerically. The present study offers a fundamental understanding of frontal polymerization in the presence of heat-absorbing second-phase materials and proposes a potential one-step manufacturing method for precisely patterned polymeric and composite materials without masks, molds, or printers.

Conjugated Polymer for Implantable Electronics toward Clinical Application

Owing to their excellent mechanical flexibility, mixed-conducting electrical property, and extraordinary chemical turnability, conjugated polymers have been demonstrated to be an ideal bioelectronic interface to deliver therapeutic effect in many different chronic diseases. This review article summarizes the latest advances in implantable electronics using conjugated polymers as electroactive materials and identifies remaining challenges and opportunities for developing electronic medicine. Examples of conjugated polymer-based bioelectronic devices are selectively reviewed in human clinical studies or animal studies with the potential for clinical adoption. The unique properties of conjugated polymers are highlighted and exemplified as potential solutions to address the specific challenges in electronic medicine.

Conducting/biodegradable chitosan-polyaniline film; Antioxidant, color, solubility and water vapor permeability properties

In this study, chitosan-polyaniline nanocomposite film was prepared in combination with different concentrations of polyaniline at various synthesis times. Surface morphology, antioxidant properties, water solubility, water vapor permeability (WVP), color properties and light transparency properties of the films were investigated. The size, shape and morphology of the synthesized particles were examined with scanning electron microscopy (SEM) technique. The results indicated that the synthesized polyaniline particles were spherical and in the range of 45–70 nm. The results obtained from the study of the effect of polyaniline on the physical properties of the chitosan film showed that increasing polyaniline concentration and synthesis time causes a decrease in the rate of the water solubility and water vapor permeability. This is an important factor in expanding its use in food packaging. The results of the colorimetric studies showed that the polyaniline sharply changed the surface color of the film. Polyaniline also increased antioxidant properties of composite film. Investigating the light transmission and transparency of the films showed that the polyaniline reduced the transparency and transmission of light, which could be used to package products that are susceptible to oxidation in the light.

Preparations, Properties, and Applications of Polyaniline and Polyaniline Thin Films-A Review

Polyaniline (PANI) is a famous conductive polymer, and it has received tremendous consideration from researchers in the field of nanotechnology for the improvement of sensors, optoelectronic devices, and photonic devices. PANI is doped easily by different acids and dopants because of its easy synthesis and remarkable environmental stability. This review focuses on different preparation processes of PANI thin film by chemical and physical methods. Several features of PANI thin films, such as their magnetic, redox, and antioxidant, anti-corrosion, and electrical and sensing properties, are discussed in this review. PANI is a highly conductive polymer. Given its unique properties, easy synthesis, low cost, and high environmental stability in various applications such as electronics, drugs, and anti-corrosion materials, it has attracted extensive attention. The most important PANI applications are briefly reviewed at the end of this review.

Continuous and Patterned Conducting Polymer Coatings on Diverse Substrates: Rapid Fabrication by Oxidant-Intermediated Surface Polymerization and Application in Flexible Devices

Conducting polymer coatings and patterns are the most important forms of these materials for many practical applications, but a simple and efficient approach to these forms remains challenging. Herein, we report a universal oxidant-intermediated surface polymerization (OISP) for the fabrication of conducting polymer coatings and patterns on various substrates. A coating or pattern composed of densely packed colloidal V₂O₅·nH₂O nanowires is deposited on the substrate via spin coating, dip coating, or printing, which is converted into a conducting polymer one after in situ oxidation polymerization. The polymerization occurs selectively on the V₂O₅·nH₂O coatings, and high-quality polypyrrole, polyaniline, and poly(3,4-ethylenedioxythiophene) coatings and patterns on planar and curved polymeric, metallic, and ceramic substrates are obtained in a fast reaction rate similar to the electrochemical polymerization. The mechanistic study reveals that the method relies on the excellent processability and formability of V₂O₅·nH₂O nanowires, which is further explained by their large aspect ratio and surface activity. A flexible gas sensor array comprising three individual sensors made of different conducting polymers is fabricated using oxidant-intermediated surface polymerization, and it is successfully used to distinguish various analyte vapors. The method developed here will provide a powerful tool for the fabrication of conducting polymer-based devices.

Properties of the Composites Made of Glauconite and Polyaniline in Aqueous Solutions of Phosphoric Acid

Properties of the Composites Made of Glauconite and Polyaniline in Aqueous Solutions of Phosphoric Acid

Electrochemical Biosensors Based on Conducting Polymers: A Review

Conducting polymers are an important class of functional materials that has been widely applied to fabricate electrochemical biosensors, because of their interesting and tunable chemical, electrical, and structural properties. Conducting polymers can also be designed through chemical grafting of functional groups, nanostructured, or associated with other functional materials such as nanoparticles to provide tremendous improvements in sensitivity, selectivity, stability and reproducibility of the biosensor’s response to a variety of bioanalytes. Such biosensors are expected to play a growing and significant role in delivering the diagnostic information and therapy monitoring since they have advantages including their low cost and low detection limit. Therefore, this article starts with the description of electroanalytical methods (potentiometry, amperometry, conductometry, voltammetry, impedometry) used in electrochemical biosensors, and continues with a review of the recent advances in the application of conducting polymers in the recognition of bioanalytes leading to the development of enzyme based biosensors, immunosensors, DNA biosensors, and whole-cell biosensors.

Study of redox and protonation processes of polyaniline by the differential multiwavelength Raman spectroelectrochemistry

Polyaniline layer has been deposited at a gold electrode and subjected to differential multiwavelength Raman spectroelectrochemical study. A broad set of laser line excitation wavelengths was used, including UV (325 nm), blue (442 nm), green (532 nm), red (633 nm), and far red (785 nm). From measurements performed, potential-difference Raman spectra, related to small-step changes of electrode potential were derived, and specific spectral and structural features were obtained and analysed. Similarly, pH-difference spectra for solution pH changes were obtained. A strong resonance enhancement of Raman spectra for reduced form of polyaniline at UV and blue line excitations, and for oxidized forms at red and far red excitations was observed and analysed. The 442-nm excited potential-difference resonance Raman spectra revealed presence of intermediate oxidation state compound formed during the electrooxidation of leucoemeraldine with characteristic vibrational bands at 1622, 1187, 881, and 817 cm^-1.

Magnetic polymer microcapsules loaded with Nile Red fluorescent dye

Fabrication of multifunctional smart vehicles for drug delivery is a fascinating challenge of multidisciplinary research at the crossroads of materials science, physics and biology. We demonstrate a prototypical microcapsule system that is capable of encapsulating hydrophobic molecules and at the same time reveals magnetic properties. The microcapsules are prepared using a templated synthesis approach where the molecules to be encapsulated (Nile Red) are present in the organic droplets that are suspended in the polymerization solution which also contains magnetic nanoparticles. The polymer (polypyrrole) grows on the surface of organic droplets encapsulating the fluorescent dye in the core of the formed microcapsule which incorporates the nanoparticles into its wall. For characterization of the resulting structures a range of complementary physicochemical methodology is used including optical and electron microscopy, magnetometry, ¹H NMR and spectroscopy in the visible and X-ray spectral ranges. Moreover, the microcapsules have been examined in biological environment in in vitro and in vivo studies.

Modification of Aspergillus niger by conducting polymer, Polypyrrole, and the evaluation of electrochemical properties of modified cells

The enhancement of bioelectrochemical properties of microorganism by in situ formation of conducting polymer within the cell structures (e.g. cell wall) was performed. The synthesis of polypyrrole (Ppy) within fungi (Aspergillus niger) cells was achieved. Two different Aspergillus niger strains were selected due to their ability to produce glucose oxidase, which initiated the Ppy formation through products of enzymatic reaction. The evolution of Ppy structural features was investigated by absorption spectroscopy, cyclic voltammetry and Fourier transform infrared spectroscopy.

Electrically conductive MEH-PPV:PCL electrospun nanofibres for electrical stimulation of rat PC12 pheochromocytoma cells

Electrically conductive, porous, mechanically strong and bioactive electrospun MEH-PPV:PCL nanofibres with blended and core-sheath formulations for enhanced neurite formation and neurite outgrowth.

Two-dimensional polyaniline nanostructure to the development of microfluidic integrated flexible biosensors for biomarker detection

In this work, we report a flexible field-effect-transistor (FET) biosensor design based on two-dimensional (2-D) polyaniline (PANI) nanostructure. The flexible biosensor devices were fabricated through a facile and inexpensive method that combines top-down and bottom-up processes. The chemically synthesized PANI nanostructure showed excellent p-type semiconductor properties as well as good compatibility with flexible design. With the 2-D PANI nanostructure being as thin as 80 nm and its extremely large surface-area-to-volume (SA/V) ratio due to the intrinsic properties of PANI chemical synthesis, the developed flexible biosensor exhibited outstanding sensing performance in detecting B-type natriuretic peptide (BNP) biomarkers, and was able to achieve high specificity (averagely 112 folds) with the limit of detection as low as 100 pg/mL. PANI nanostructure under bending condition was also investigated and showed controllable conductance changes being less than 20% with good restorability which may open up the possibility for wearable applications.

Substrate coating by conductive polymers through spontaneous oxidation and polymerization

A variety of substrates and substances were coated with conductive polymers at low temperature under ambient pressure. The substrate coating with heteroaromatic polymers proceeded through spontaneous oxidation and polymerization of the monomers, such as pyrrole (Py) and thiophene (Tp) derivatives. The monomer liquid, the solid nitrate oxidant, and the substrate were put in a closed vessel. The vapor of the activated monomer was spontaneously generated on the surface of the solid nitrate oxidant through the diffusion of the monomer vapor. The monomer and its activated species were adsorbed and polymerized on the surface of any substrate in the reaction vessel. The thickness was controlled by the reaction time. The substituents of the monomers had an influence on the coating rate. The morphology of the coated polymers was changed by the substrates with different wettabilities. The thin coating of the heteroaromatic polymer was applied to the preparation of an electrode for charge storage based on the redox reaction. The thin coating on the current collector showed an enhanced high-rate charge-discharge performance. The present synthetic approach can be applied to the coating of polymer materials on a variety of substrates from the monomer vapor under mild conditions.

Research on DC dielectric properties of polyaniline nanofibers/LDPE composites

In this article, polyaniline (PANI) nanofibers were prepared and added to low-density polyethylene (LDPE) to produce PANI nanofibers/LDPE composites. LDPE and the composites were tested for direct current (DC) conductivity, breakdown strength, and space charge characteristics. The results suggested that DC breakdown strength of PANI nanofibers/LDPE composites significantly declined once PANI was added, and the decline was more evident with the increase of PANI nanofibers. Meanwhile, the addition of PANI nanofibers contributed to a decrease in the conductivity of LDPE. As the content of PANI nanofibers increased, the conductivity of the composites declined first and then raised. DC conductivity properties of LDPE could be improved by adding an appropriate amount of PANI nanofibers. Compared with LDPE, the space charge distribution was changed in LDPE due to the addition of PANI nanofibers. With the increase of content of PANI nanofibers, the amount of space charges close to the electrodes decreased gradually.

Polyaniline-Coated Carbon Nanotube Ultrafiltration Membranes: Enhanced Anodic Stability for In Situ Cleaning and Electro-Oxidation Processes

Electrically conducting membranes (ECMs) have been reported to be efficient in fouling prevention and destruction of aqueous chemical compounds. In the current study, highly conductive and anodically stable composite polyaniline-carbon nanotube (PANI-CNT) ultrafiltration (UF) ECMs were fabricated through a process of electropolymerization of aniline on a CNT substrate under acidic conditions. The resulting PANI-CNT UF ECMs were characterized by scanning electron microscopy, atomic force microscopy, a four-point conductivity probe, cyclic voltammetry, and contact angle goniometry. The utilization of the PANI-CNT material led to significant advantages, including: (1) increased electrical conductivity by nearly an order of magnitude; (2) increased surface hydrophilicity while not impacting membrane selectivity or permeability; and (3) greatly improved stability under anodic conditions. The membrane's anodic stability was evaluated in a pH-controlled aqueous environment under a wide range of anodic potentials using a three-electrode cell. Results indicate a significantly reduced degradation rate in comparison to a CNT-poly(vinyl alcohol) ECM under high anodic potentials. Fouling experiments conducted with bovine serum albumin demonstrated the capacity of the PANI-CNT ECMs for in situ oxidative cleaning, with membrane flux restored to its initial value under an applied potential of 3 V. Additionally, a model organic compound (methylene blue) was electrochemically transformed at high efficiency (90%) in a single pass through the anodically charged ECM.

Nanotechnology in Textiles

Increasing customer demand for durable and functional apparel manufactured in a sustainable manner has created an opportunity for nanomaterials to be integrated into textile substrates. Nanomoieties can induce stain repellence, wrinkle-freeness, static elimination, and electrical conductivity to fibers without compromising their comfort and flexibility. Nanomaterials also offer a wider application potential to create connected garments that can sense and respond to external stimuli via electrical, color, or physiological signals. This review discusses electronic and photonic nanotechnologies that are integrated with textiles and shows their applications in displays, sensing, and drug release within the context of performance, durability, and connectivity. Risk factors including nanotoxicity, nanomaterial release during washing, and environmental impact of nanotextiles based on life cycle assessments have been evaluated. This review also provides an analysis of nanotechnology consolidation in the textiles market to evaluate global trends and patent coverage, supplemented by case studies of commercial products. Perceived limitations of nanotechnology in the textile industry and future directions are identified.