A Highly Sensitive Ammonia Gas Sensor Using Micrometer-Sized Core-Shell-Type Spherical Polyaniline Particles.
Ontology highlight
ABSTRACT:
SUBMITTER: Matsuguchi M
PROVIDER: S-EPMC8619626 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:A new structure of a flexible, transparent polyaniline (PANI) ammonia gas sensor is reported. The sensor features a hierarchical nanostructured PANI polymer arranged in a micromesh, exhibiting excellent chemiresistive sensitivity to ammonia gas and near-neutral color transparency. The PANI mesh is embedded in a flexible substrate and therefore exhibits superior mechanical stability against peeling and bending. These merits make it a promising candidate for application in wearable electronics. Moreover, the PANI mesh sensor is fabricated through a cost-effective, solution-based strategy that enables vacuum-free fabrication of a sacrificial catalytic copper mesh followed by in situ polymerization, and this strategy is scalable for high-volume production. We demonstrate the high-performance resistive sensing of ammonia gas with concentrations from 2.5 ppb to 100 ppm using this flexible PANI mesh sensor with an excellent transparency of 88.4% at 600 nm wavelength. Furthermore, no significant degradation in the sensing performance occurs after 1000 bending cycles.
| S-EPMC9078194 | biostudies-literature
Project description:The ability to study individual bacteria or subcellular organelles using inertial microfluidics is still nascent. This is due, in no small part, to the significant challenges associated with concentrating and separating specific sizes of micrometer and sub-micrometer bioparticles in a microfluidic format. In this study, using a rigid polymeric microfluidic network with optimized microchannel geometry dimensions, it is demonstrated that 2 µm, and even sub-micrometer, particles can be continuously and accurately focused to stable equilibrium positions. Suspensions have been processed at flow rates up to 1400 µL min-1 in an ultrashort 4 mm working channel length. A wide range of suspension concentrations-from 0.01 to 1 v/v%-have been systematically investigated, with yields greater than 97%, demonstrating the potential of this technology for large-scale implementation. Additionally, the ability of this chip to separate micrometer- and sub-micrometer-sized particles and to focus bioparticles (cyanobacteria) has been demonstrated. This study pushes the microfluidic inertial focusing particle range down to sub-micrometer length scales, enabling novel routes for investigation of individual microorganisms and subcellular organelles.
| S-EPMC5644225 | biostudies-literature
Project description:Core/shell pigments allow for the combination of the active anti-corrosion effect of the shell and the barrier effect of the core. This makes it possible to obtain anti-corrosion pigments, with a high-protective effect and low toxicity. Thus, the need for a comprehensive study of the properties of these pigments grows more urgent, before their application to paints and varnishes. The hiding power of core/shell pigments comes close to the one of pure polyaniline (PANi), when the PANi content in the pigment reaches 50 wt.%, with sulfuric and phosphoric acids used as dopants. This paper, also, shows that the blackness value of core/shell pigments with 10 wt.% PANi is around 35 and constant; for pure PANi, their blackness value is 40. When PANi content is 5 wt.%, kaolin-based pigment shows the lowest blackness, which happens due to a generally higher whiteness of kaolin. However, when the PANi content surpasses 10 wt.%, there seems to be no influence on the blackness of the core/shell pigments. The core/shell pigment with a 20 wt.% PANi is, optically, identical to a black-iron-oxide pigment. An increase in the PANi content of the core/shell pigment leads to an increase in the oil absorption of the samples. It was found that the dispersion process would be the most energy efficient for core/shell pigments, containing kaolin and talc as a core.
| S-EPMC9144958 | biostudies-literature
Project description:Well-defined sterically stabilized diblock copolymer nanoparticles of 29 nm diameter are prepared by RAFT aqueous emulsion polymerization of methyl methacrylate using a dithiobenzoate-capped poly(glycerol monomethacrylate) precursor. These nanoparticles are evaluated as a dispersant for the preparation of organic crystalline microparticles via ball milling. This is exemplified for azoxystrobin, which is a broad-spectrum fungicide that is widely used to protect various food crops. Laser diffraction and optical microscopy studies indicate the formation of azoxystrobin microparticles of approximately 2 μm diameter after ball milling for 10 min at 400 rpm. Nanoparticle adsorption at the surface of these azoxystrobin microparticles is confirmed by electron microscopy studies. The extent of nanoparticle adsorption on the azoxystrobin microparticles can be quantified using a supernatant assay based on solution densitometry. This technique indicates an adsorbed amount of approximately 5.5 mg m-2, which is sufficient to significantly reduce the negative zeta potential exhibited by azoxystrobin. Moreover, this adsorbed amount appears to be essentially independent of the nature of the core-forming block, with similar data being obtained for both poly(methyl methacrylate)- and poly(2,2,2-trifluoroethyl methacrylate)-based nanoparticles. Finally, X-ray photoelectron spectroscopy studies confirm attenuation of the underlying N1s signal arising from the azoxystrobin microparticles by the former adsorbed nanoparticles, suggesting a fractional surface coverage of approximately 0.24. This value is consistent with a theoretical surface coverage of 0.25 calculated from the adsorption isotherm data. Overall, this study suggests that sterically stabilized diblock copolymer nanoparticles may offer a useful alternative approach to traditional soluble copolymer dispersants for the preparation of suspension concentrates affecting the context of agrochemical applications.
| S-EPMC8289232 | biostudies-literature
Project description:A single-yarn-based gas sensor has been made from conductive polyaniline coated on commercial yarns. This can detect ammonia gas concentration in an environment or a working area. Cotton, rayon and polyester are utilized as substrates using a dip-coating process. The conductive yarns show ohmic behavior with an electrical resistance of 15-31 kΩ cm-1. The conductive polyester yarn exhibits higher mechanical strength even after intensive chemical treatment. It also has the highest gas response of 57% of 50 ppm ammonia gas, the concentration at which health problems will occur. A linear gas response of the yarn sensor appears in a range of 5-25 ppm ammonia concentration. The polyester yarn sensor can be reused without any change in its sensing response. It can monitor gas levels continuously giving real-time results. By using a microcontroller as part of the circuitry, the gas detection results are transferred and updated wirelessly to a computer or to a smartphone. The textile-based gas sensor can be sewn directly onto the fabrics since it is made with the same fabric. This single-yarn-based gas sensor is suitable for mass production and is appropriate for sophisticated applications.
| S-EPMC9070429 | biostudies-literature
Project description:A series of linear cationic diblock copolymer nanoparticles are prepared by polymerization-induced self-assembly (PISA) via reversible addition-fragmentation chain transfer (RAFT) aqueous dispersion polymerization of 2-hydroxypropyl methacrylate (HPMA) using a binary mixture of non-ionic and cationic macromolecular RAFT agents, namely poly(ethylene oxide) (PEO113, Mn = 4400 g mol-1; Mw/Mn = 1.08) and poly([2-(methacryloyloxy)ethyl]trimethylammonium chloride) (PQDMA125, Mn = 31?800 g mol-1, Mw/Mn = 1.19). A detailed phase diagram was constructed to determine the maximum amount of PQDMA125 stabilizer block that could be incorporated while still allowing access to a pure worm copolymer morphology. Aqueous electrophoresis studies indicated that zeta potentials of +35 mV could be achieved for such cationic worms over a wide pH range. Core cross-linked worms were prepared via statistical copolymerization of glycidyl methacrylate (GlyMA) with HPMA using a slightly modified PISA formulation, followed by reacting the epoxy groups of the GlyMA residues located within the worm cores with 3-aminopropyl triethoxysilane (APTES), and concomitant hydrolysis/condensation of the pendent silanol groups with the secondary alcohol on the HPMA residues. TEM and DLS studies confirmed that such core cross-linked cationic worms remained colloidally stable when challenged with either excess methanol or a cationic surfactant. These cross-linked cationic worms are shown to be much more effective bridging flocculants for 1.0 ?m silica particles at pH 9 than the corresponding linear cationic worms (and also various commercial high molecular weight water-soluble polymers.). Laser diffraction studies indicated silica aggregates of around 25-28 ?m diameter when using the former worms but only 3-5 ?m diameter when employing the latter worms. Moreover, SEM studies confirmed that the cross-linked worms remained intact after their adsorption onto the silica particles, whereas the much more delicate linear worms underwent fragmentation under the same conditions. Similar results were obtained with 4 ?m silica particles.
| S-EPMC5450592 | biostudies-literature
Project description:Wear debris in joint replacements has been suggested as a cause of associated tissue-damaging inflammation. In this study, we examined whether solid titanium microparticles (mTi) of sufficient size to accumulate as wear debris could stimulate innate or adaptive immunity in vivo. mTi, administered in conjunction with OVA, promoted total and Ag-specific elevations in serum IgE and IgG1. Analysis of transferred transgenic OVA-specific naive T cells further showed that mTi acted as an adjuvant to drive Ag-specific Th2 cell differentiation in vivo. Assessment of the innate response indicated that mTi induced rapid recruitment and differentiation of alternatively activated macrophages in vivo, through IL-4- and TLR4-independent pathways. These studies suggest that solid microparticles alone can act as adjuvants to induce potent innate and adaptive Th2-type immune responses and further suggest that wear debris in joint replacements may have Th2-type inflammatory properties.
| S-EPMC3237784 | biostudies-literature
Project description:Nanocomposites (NCs) of crosslinked polyaniline (CPA)-coated oxidized carbon nanomaterials (OXCNMs) were fabricated as a very sensitive and simple electrochemical sensor to be utilized in 2,4-dichlorophenol (2,4-DCPH) detection. CPA/OXCNMs NCs were prepared by chemical copolymerization of polyaniline with triphenylamine and p-phenylenediamine in the presence of OXCNMs. The CPA/GO-OXSWCNTNCs exhibited a higher affinity for the oxidation of chlorophenols compared to the glassy carbon electrode (GCE), CPA/GCE, and other NCs. Cyclic voltammetry was performed to investigate and assess the electrocatalytic oxidation of 2,4-DCPH on the modified GCE. The compound yielded a well-defined voltammetric response in a Britton-Robinson buffer (pH 5) at 0.54 V (vs. silver chloride electrode). Quantitative determination of 2,4-DCPH was performed by differential pulse voltammetry under optimal conditions in the concentration range of 0.05 to 1.2 nmol L-1, and a linear calibration graph was obtained. The detection limit (S/N = 3) was found to be 4.2 nmol L-1. In addition, the results demonstrated that the CPA/GO-OXSWCNTs/GCE sensor exhibited a strong anti-interference ability, reproducibility, and stability. The prepared CPA/GO-OXSWCNTs/GCE sensor was used to rapidly detect 2,4-DCPH with a high degree of sensitivity in fish farm water with proven levels of satisfactory recoveries.
| S-EPMC7316237 | biostudies-literature
Project description:Hybrid materials of electrically conducting polymers and inorganic semiconductors form an exciting class of functional materials. To fully exploit the potential synergies of the hybrid formation, however, sophisticated synthetic methods are required that allow for the fine-tuning of the nanoscale structure of the organic/inorganic interface. Here we present the photocatalytic deposition of a conducting polymer (polyaniline) on the surface of silicon carbide (SiC) nanoparticles. The polymerization is facilitated on the SiC surface, via the oxidation of the monomer molecules by ultraviolet-visible (UV-vis) light irradiation through the photogenerated holes. The synthesized core-shell nanostructures were characterized by UV-vis, Raman, and Fourier Transformed Infrared (FT-IR) Spectroscopy, thermogravimetric analysis, transmission and scanning electron microscopy, and electrochemical methods. It was found that the composition of the hybrids can be varied by simply changing the irradiation time. In addition, we proved the crucial importance of the irradiation wavelength in forming conductive polyaniline, instead of its overoxidized, insulating counterpart. Overall, we conclude that photocatalytic deposition is a promising and versatile approach for the synthesis of conducting polymers with controlled properties on semiconductor surfaces. The presented findings may trigger further studies using photocatalysis as a synthetic strategy to obtain nanoscale hybrid architectures of different semiconductors.
| S-EPMC5456665 | biostudies-other
Project description:The next future strategies for improved occupational safety and health management could largely benefit from wearable and Internet of Things technologies, enabling the real-time monitoring of health-related and environmental information to the wearer, to emergency responders, and to inspectors. The aim of this study is the development of a wearable gas sensor for the detection of NH3 at room temperature based on the organic semiconductor poly(3,4-ethylenedioxythiophene) (PEDOT), electrochemically deposited iridium oxide particles, and a hydrogel film. The hydrogel composition was finely optimised to obtain self-healing properties, as well as the desired porosity, adhesion to the substrate, and stability in humidity variations. Its chemical structure and morphology were characterised by infrared spectroscopy and scanning electron microscopy, respectively, and were found to play a key role in the transduction process and in the achievement of a reversible and selective response. The sensing properties rely on a potentiometric-like mechanism that significantly differs from most of the state-of-the-art NH3 gas sensors and provides superior robustness to the final device. Thanks to the reliability of the analytical response, the simple two-terminal configuration and the low power consumption, the PEDOT:PSS/IrOx Ps/hydrogel sensor was realised on a flexible plastic foil and successfully tested in a wearable configuration with wireless connectivity to a smartphone. The wearable sensor showed stability to mechanical deformations and good analytical performances, with a sensitivity of 60 ± 8 μA decade-1 in a wide concentration range (17-7899 ppm), which includes the safety limits set by law for NH3 exposure.
| S-EPMC8659774 | biostudies-literature