Nanostructured conducting polypyrrole film prepared by chemical vapor deposition on the interdigital electrodes at room temperature under atmospheric condition and its application as gas sensor

Dual-responsive fluorescence probe for measuring HSO3- and viscosity and its application in living cells and real foods

Microenvironmental indicators in organisms drive the operation of different physiological functions. In contrast, disruption of microenvironmental homeostasis is often closely associated with various pathological processes. A novel dual-response fluorescent probe based on hemicyanine dye (HT-Bzh) was designed and synthesized for the detection of HSO3- and viscosity changes. The probe not only provides high sensitivity (limit of detection = 0.2526 μM) for the detection of HSO3- using the Michael addition reaction, but also allows the observation of fluorescence emission at 528 nm and thus the monitoring of viscosity changes through hindering of the twisted intramolecular charge transfer (TICT) mechanism. Additionally, dual-response probe has been successfully used to image living cells and detect real food samples. As a new designed tool, HT-Bzh shows excellent anti-interference capability and biocompatibility, which makes it have application potential in other biological systems and in-vivo imaging.

Recent advances in conducting polymer-based magnetic nanosorbents for dyes and heavy metal removal: fabrication, applications, and perspective

Globally, treating and disposing of industrial pollutants is a techno-economic challenge. Industries' large production of harmful heavy metal ions (HMIs) and dyes and inappropriate disposal worsen water contamination. Much attention is required on the development of efficient and cost-effective technologies and approaches for removing toxic HMIs and dyes from wastewater as they pose a severe threat to public health and aquatic ecosystems. Due to the proven superiority of adsorption over other alternative methods, various nanosorbents have been developed for the efficient removal of HMIs and dyes from wastewater and aqueous solutions. Being a good adsorbent, conducting polymer-based magnetic nanocomposites (CP-MNCPs) has drawn more attention for HMIs and dye removal. Conductive polymers' pH-responsiveness makes CP-MNCP ideal for wastewater treatment. The composite material absorbed dyes and/or HMIs from contaminated water could be removed by changing the pH. Here, we review the production strategies and applications of CP-MNCPs for HMIs and dye removal. The review also sheds light on the adsorption mechanism, adsorption efficiency, kinetic and adsorption models, and regeneration capacity of the various CP-MNCPs. To date, various modifications to conducting polymers (CPs) have been explored to improve the adsorption properties. It is evident from the literature survey that the combination of SiO₂, graphene oxide (GO), and multi-walled carbon nanotubes (MWCNTs) with CPs-MNCPs enhances the adsorption capacity of nanocomposites to a large extent, so future research should lean toward the development of cost-effective hybrid CPs-nanocomposites.

Application of Polypyrrole-Based Electrochemical Biosensor for the Early Diagnosis of Colorectal Cancer

Although colorectal cancer (CRC) is easy to treat surgically and can be combined with postoperative chemotherapy, its five-year survival rate is still not optimistic. Therefore, developing sensitive, efficient, and compliant detection technology is essential to diagnose CRC at an early stage, providing more opportunities for effective treatment and intervention. Currently, the widely used clinical CRC detection methods include endoscopy, stool examination, imaging modalities, and tumor biomarker detection; among them, blood biomarkers, a noninvasive strategy for CRC screening, have shown significant potential for early diagnosis, prediction, prognosis, and staging of cancer. As shown by recent studies, electrochemical biosensors have attracted extensive attention for the detection of blood biomarkers because of their advantages of being cost-effective and having sound sensitivity, good versatility, high selectivity, and a fast response. Among these, nano-conductive polymer materials, especially the conductive polymer polypyrrole (PPy), have been broadly applied to improve sensing performance due to their excellent electrical properties and the flexibility of their surface properties, as well as their easy preparation and functionalization and good biocompatibility. This review mainly discusses the characteristics of PPy-based biosensors, their synthetic methods, and their application for the detection of CRC biomarkers. Finally, the opportunities and challenges related to the use of PPy-based sensors for diagnosing CRC are also discussed.

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.

Rational Confinement of Yttrium Vanadate within Three-Dimensional Graphene Aerogel: Electrochemical Analysis of Monoamine Neurotransmitter (Dopamine)

Real-time monitoring of neurotransmitter levels is of tremendous technological demand, which requires more sensitive and selective sensors over a dynamic concentration range. As a use case, we report yttrium vanadate within three-dimensional graphene aerogel (YVO/GA) as a novel electrocatalyst for detecting dopamine (DA). This synergy effect endows YVO/GA nanocomposite with good electrochemical behaviors for DA detection compared to other electrodes. Benefiting from tailorable properties, it provides a large specific surface area, rapid electron transfer, more active sites, good catalytic activity, synergic effect, and high conductivity. The essential analytical parameters were estimated from the calibration plot, such as a limit of detection (1.5 nM) and sensitivity (7.1 μA μM^-1 cm^-2) with the YVO/GA sensor probe electrochemical approach. The calibration curve was fitted with the correlation coefficient of 0.994 in the DA concentration range from 0.009 to 83 μM, which is denoted as the linear working range. We further demonstrate the proposed YVO/GA sensor's applicability to detect DA in human serum sample with an acceptable recovery range. Our results imply that the developed sensor could be applied to the early analysis of dementia, psychiatric, and neurodegenerative disorders.

Recent Progress and Perspectives on Polyurethane Membranes in the Development of Gas Sensors

In today's technology, gas sensors are of great importance in areas such as assessing environmental impacts, monitoring gas production facilities, measuring natural gas, controlling mines and gas leaks. Improving sensor sensitivity and decreasing the determination time is among the subjects that are continuously investigated. The use of polymeric membranes to make such improvements is common practice in the gas sensor field. By the development of polymeric membrane-based gas sensors and increasing the measurement sensitivity, accurate, sensitive, precise and fast measurements of toxic gases, volatile organic gases, and trace gases have been possible. Therefore, polyurethane membranes have been promising in the development of next-generation gas sensors based on membrane diffusion to ensure real-time and continuous monitoring of gases in industry and academic studies. This study aims to evaluate, compare and discuss the recent developments in the use of polyurethane membranes in existing gas detection technologies with chemical, electrical and optical measurement methods. In these measurement methods, polyurethane structures act as a selectively permeable membrane, an ideal matrix material for conductive additives or a suitable film structure for coating the conductive polymeric films. Conductive additives or conductive film structures for gas sensors play an important role in the detection of the gas structure with the change in electrical properties during the passage of gas molecules. This review has focused on important properties such as selectivity, detection time and measurement sensitivity concerning gas detection technology containing polyurethane, which has been used so far.

Vapor/liquid polymerization of ultraporous transparent and capacitive polypyrrole nanonets

Freestanding, contiguous, and translucent polypyrrole nanonets are prepared within 90 minutes at room temperature in Petri dishes by exposing aqueous oxidant to static pyrrole vapor. The nanonets are 150 nm thick, with variable densities depending on polymerization time. The nanonets maintain a low sheet resistance of 29.1 Ω□^-1 at 30% optical transmission, and 423 Ω□^-1 at 50% transmission. A mechanism is proposed in which polypyrrole islands serve as nucleation sites for further surface-tension constrained polymerization. The nanonets exhibit a high degree of electrochemical dopability (over 24%). Nets are robust and processable, as evidenced by their ability to drape over 2D and 3D substrates. Large areas of films are manually twisted into highly porous sub-millimeter diameter conductive wires, able to recover their two-dimensional structure upon immersion in solvents. Moreover, nanonets exhibit a high specific capacitance of 518 F g^-1 for a 1.2 V potential window. Electrochemical capacitors fabricated with nanonet active electrodes show a high energy density of 9.86 W h kg^-1 at 1775 W kg^-1 when charged to 0.8 V.

Study on poly(tetrafluoroethylene-co-hexafluoropropylene) hollow fiber membranes with surface modification by a chemical vapor deposition method

FEP/PPy composite hollow fiber membranes were prepared by PPy layer polymerization on the outer surface of FEP hollow fiber membranesviaa chemical vapor deposition method.

CVD Polymers for Devices and Device Fabrication

Chemical vapor deposition (CVD) polymerization directly synthesizes organic thin films on a substrate from vapor phase reactants. Dielectric, semiconducting, electrically conducting, and ionically conducting CVD polymers have all been readily integrated into devices. The absence of solvent in the CVD process enables the growth of high-purity layers and avoids the potential of dewetting phenomena, which lead to pinhole defects. By limiting contaminants and defects, ultrathin (<10 nm) CVD polymeric device layers have been fabricated in multiple laboratories. The CVD method is particularly suitable for synthesizing insoluble conductive polymers, layers with high densities of organic functional groups, and robust crosslinked networks. Additionally, CVD polymers are prized for the ability to conformally cover rough surfaces, like those of paper and textile substrates, as well as the complex geometries of micro- and nanostructured devices. By employing low processing temperatures, CVD polymerization avoids damaging substrates and underlying device layers. This report discusses the mechanisms of the major CVD polymerization techniques and the recent progress of their applications in devices and device fabrication, with emphasis on initiated CVD (iCVD) and oxidative CVD (oCVD) polymerization.