Search Results (169)

In this work, monodisperse carbon microspheres with an average diameter of approximately 900 nm were successfully synthesized via a hydrothermal method. To further tailor their surface properties, the layer-by-layer (LbL) self-assembly technique was employed, where the cationic polyelectrolyte poly(diallyldimethylammonium chloride) (PDDA) and the anionic polyelectrolyte poly(styrene sulfonate) (PSS) were alternately deposited on the microsphere surface, forming two and four bilayer assemblies, respectively. The resulting composite microspheres exhibited remarkable adsorption performance toward representative dyes in water solution, such as rhodamine B (RhB) and methylene blue (MB). Experimental results demonstrated that the incorporation of a single bilayer significantly reduced the specific surface area but introduced additional active adsorption sites, thereby enhancing dye removal efficiency. However, when the number of bilayers was further increased to two, partial pore coverage and blockage occurred, leading to a reduced surface area and consequently diminished adsorption capacity. These findings highlight that in LbL surface modification, more layers do not necessarily yield better performance, but rather an optimal assembly thickness exists. This insight provides valuable guidance for the rational design of advanced adsorbent materials for wastewater treatment. Full article

The hole injection layer (HIL) plays a critical role in achieving high efficiency and operational stability in organic light-emitting diodes (OLEDs). As a commonly used HIL, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is limited by its intrinsically low electrical conductivity and mismatched work function alignment with the hole transport layer (HTL), leading to inefficient hole injection and carrier imbalance. In this work, a mild citric acid (CA) treatment is used to simultaneously enhance the conductivity of PEDOT:PSS through the partial removal of insulating PSS and tune its work function for improved energy level alignment at the anode interface. This simultaneous optimization effectively enhances the hole transport capability, successfully matching the electron transport capability to realize highly improved charge carrier balance within the device. Consequently, Ir(ppy)₃-based phosphorescent OLEDs featuring the optimally treated PEDOT:PSS HIL deliver a maximum external quantum efficiency of 20.37%, representing a 21% improvement over devices using pristine PEDOT:PSS, along with a twofold extension in operational lifetime. This strategy demonstrates a simple and controllable approach to interfacial engineering, providing practical guidance for the development of high-performance and stable OLEDs. Full article

Conducting polymers (CPs) have become cornerstone materials in electrochemical sensors and biosensors due to their mixed ionic–electronic conduction, mechanical softness, and intrinsic biointerface compatibility. This review provides a comprehensive and critical overview of the field, tracing the evolution of CP-based devices from classical poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), polyaniline (PANI), and polypyrrole (PPy) electrodes to emerging nanostructured, hybrid, wearable, and transient systems. We discuss fundamental charge-transport mechanisms, doping strategies, structure–property relationships, and the role of morphology and biofunctionalization in dictating sensitivity, selectivity, and stability. Particular emphasis is placed on reliability challenges—including drift, dopant leaching, environmental degradation, and biofouling—and on the current lack of standardized metrology, which hampers cross-study comparability. We propose a framework for rigorous calibration, reference electrode design, and data reporting, enabling quantitative benchmarking across materials and architectures. To support meaningful cross-platform comparison, representative performance envelopes—including conductivity, limit of detection, sensitivity, selectivity strategies, and operational stability—are critically benchmarked across major CP families and sensing modalities. Finally, we explore future directions such as organic mixed ionic–electronic conductors, biohybrid and living polymer interfaces, Artificial Intelligence-driven modeling, and sustainable transient electronics. Full article

The surface morphology of high molecular weight poly(styrene-b-isoprene) block copolymer was analyzed after chemical modification. Poly(styrene-b-isoprene) was converted into poly(styrene-b-(ethylene-alt-propylene)) by hydrogenation and into poly(styrene-b-sulfonated isoprene) by mild sulfonation of the PI block. Obtained morphologies were examined by atomic force microscopy, analyzing the effect of sample preparation parameters such as solvent (tetrahydrofuran, toluene, and cyclohexane), casting technique (spin casting and drop casting), and annealing temperature [room temperature, 80, 100, and 120 °C]. Significant morphological and topographical changes were found depending on the different parameters. Each modification step introduces new variables that can affect the final structure and properties of the copolymer. Finding the balance between solvent choice, casting technique, and annealing conditions was a difficult task and required extensive experimentation and understanding of the principles of block copolymer self-assembly. Full article

Calcium oxalate (CaOx) crystals play a central role in urolithiasis, a pathological crystallization process that remains difficult to prevent. In this study, electrospun polymeric fiber (EPF) meshes of poly(acrylic acid-co-styrene sulfonate) P(AA-co-SS) were fabricated by electrospinning (ES) under controlled positive (+) or negative (−) voltages. The influence of PAA and PSS homopolymers, as well as P(AA-co-SS) copolymers with varying compositions, was evaluated as anionic scaffolds in in vitro CaOx electrocrystallization (EC) experiments. The structural and morphological features of the EPF meshes were characterized by scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Our results demonstrate that specific EPF meshes can effectively guide CaOx crystal growth, promoting the selective stabilization of either calcium oxalate monohydrate (COM) or calcium oxalate dihydrate (COD) phases. These findings highlight the potential of tailored EPF meshes as anionic scaffolds for modulating pathological CaOx crystallization. Full article

Spin-spray-assisted layer-by-layer (LbL) assembly is an innovative method for producing nanostructured thin films due to its rapid assembly and extensive coverage of substrates. In this study, a nanofiltration (NF) membrane consisting of multilayers of polyethyleneimine (PEI) and poly(sodium-4-styrene sulfonate) (PSS) was fabricated on a polysulfone (PSF) support. The resulting membrane was further coated with a metal–organic framework (MOF303). The resulting (PEI/PSS)₅-MOF303 showed a rejection rate of 18.94 ± 1.58% and a permeability of 0.91 ± 0.13 L/(h·bar·m²)while also showing enhanced antifouling properties. This work explores the possibility of spin-spray-assisted LbL assembly as a promising method for fabricating membranes. Full article

Silica-modified electrodes possess physicochemical properties that make them valuable in electrochemical sensing and energy-related applications. Although intrinsically insulating, silica thin films can selectively interact with redox species, producing sieving effects that enhance electrochemical responses. We synthesized Class I hybrid silica matrices incorporating either negatively charged poly(4-styrene sulfonic acid) or positively charged poly(diallyl dimethylammonium chloride). These hybrid films were deposited onto ITO electrodes and evaluated via cyclic voltammetry in aqueous ferrocenium solutions. The polyelectrolyte charge played a key role in the electroassisted incorporation of ferrocene: silica-PSS films promoted accumulation, while silica-PDADMAC films hindered it due to electrostatic repulsion. In situ UV-vis spectroscopy confirmed that only a fraction of the embedded ferrocene was electroactive. Nevertheless, this fraction enabled effective mediated detection of cytochrome c in solution. These findings highlight the crucial role of ionic interactions and hybrid composition in electron transfer to redox proteins, providing valuable insights for the development of advanced bioelectronic sensors. Full article

The optical ammonia-sensing properties of water-dispersible polyaniline (PANI) complexes chemically synthesized in the presence of polysulfonic acids of different structure and chain flexibility were compared for the first time. Flexible-chain poly(styrene-4-sulfonic acid) and poly-(2-acrylamido-2-methyl-1-propanesulfonic acid), as well as semi-rigid-chain poly-4,4′-(2,2′-disulfonic acid)diphenylene-iso-phthalamide and rigid-chain poly-4,4′-(2,2′-disulfonic acid)diphenylene-tere-phthalamide (t-PASA) were used. The sensor films were prepared by a convenient and scalable method—spray coating of aqueous solutions on glass substrates. The optical response time and amplitude of the sensor films in the range of ammonia concentrations from 5 to 200 ppm were investigated. To overcome the influence of humidity and presence of over-stoichiometric protons of the polyacid on the accuracy of ammonia determination treatments of the films in aqueous solutions of NaCl, CaCl₂ and BaCl₂ were tested. The treatment in 1 M CaCl₂ solution for all of the PANI complexes results in a significant improvement in the response time, amplitude and reproducibility. The films of PANI complexes with the flexible-chain polyacids have the highest response amplitude in the range of ammonia concentrations 5–25 ppm. PANI-t-PASA film demonstrated the best sensory properties at ammonia concentrations more than 50 ppm. FTIR spectroscopy showed that CaCl₂ treatment results in cross-linking of sulfoacid groups from adjacent polyacid chains by Ca²⁺ ions. Thus, such a treatment results both in the neutralization of excessive protons and a significant reduction in the films’ swelling at high humidity. Full article

Asymmetric micro-supercapacitors (AMSCs) with a small size and high energy density can be compatible with portable and wearable electronic devices and are capable of providing stable, long-term power supply, attracting great research interest in recent years. Here, we present a simple and rapid preparation method for AMSCs’ fabrication. By regulating the hydrophilicity and hydrophobicity of coplanar laser-induced graphene (LIG) through the adjustment of the laser parameters, two electrode materials with distinct hydrophilic–hydrophobic properties were selectively deposited by sequentially dip-coating. The LIGs serve as current collectors, with activated carbon and poly (3,4-ethylenedioxythiophene): poly (styrene sulfonate) as active materials. After coating the electrolytes and folding the two electrodes, a high-performance AMSC was achieved. The device exhibits a high areal capacitance of 85.88 mF cm⁻² at a current density of 0.4 mA cm⁻², along with an impressive energy density of 11.93 µWh cm⁻² and a good rate performance. Moreover, it is demonstrated to be highly stable in 500,000 cycles. Two AMSCs in series can supply power to an electronic clock and birthday card. The method of preparing asymmetric electrodes in the same plane greatly facilitates the large-area preparation of AMSCs and series–parallel connection, providing an excellent idea for developing high-performance miniature energy storage devices. Full article

Polydimethylsiloxane (PDMS) and poly(3,4-ethylene dioxythiophene):poly(4-styrene-sulfonate) (PEDOT:PSS) composites were tested to determine their suitability for charging small-scale batteries in conjunction with a piezoelectric actuator as an energy harvester. Two different PEDOT:PSS patterns (zigzag and serpentine) were tested, and the maximum DC voltage of a system incorporating PEDOT:PSS was determined. The aim of this work is to study the effect of soft corners in the electrical routing of aircraft and IoT sensors. The zigzag and serpentine patterns were considered for this study because of their simplicity in design. Without the polymer, 2.3 V was produced by the actuator, while adding PEDOT:PSS resulted in the voltage being reduced to 1.7 V. The piezoelectric actuator was connected to a 3.6 V rechargeable Li-ion battery, and the battery’s voltage was recorded over 1 h. The voltage from the piezoelectric actuator was 3.8 V. Without PEDOT:PSS, the battery was charged to a maximum of 3 V. Adding the PEDOT:PSS to the circuit reduced the maximum charge to a voltage of 2 V. The results indicate that while PEDOT:PSS composites can be used in conjunction with piezoelectric energy harvesters, more work is still needed to optimize the system to increase efficiency and charging rates. Full article

Recent research on incorporating biomass resources into functional polymers has garnered significant attention. Poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT:PSS) is the most commercially successful conducting polymer composed of over 70 wt% petroleum-derived PSS, which presents an opportunity for partial replacement with biomass-based resources. In this study, a complex of PEDOT and sulfated cellulose nanofiber (PEDOT:s-CNF) was synthesized, and the relationship between its conductivity and doping conditions was investigated. PEDOT was synthesized on s-CNF, which was used in place of PSS, and the results indicate that conductivity increases as PEDOT polymerization progresses; however, excessive polymerization reduces electrical conductivity. Based on X-ray photoelectron spectroscopy and zeta potential measurements, the doping concentration decreases as PEDOT polymerization progresses to an excess state. This decrease is attributed to the depletion of sulfate groups, which act as dopants on s-CNFs, occurring as a consequence of the addition of PEDOT monomers. Enhancing the degree of sulfate group substitution on s-CNFs and incorporating additional dopants containing sulfonic groups improved conductivity. Specifically, adding p-toluenesulfonic acid (PTSA) as a dopant increased conductivity, reaching approximately 10 mS cm⁻¹. However, at higher PTSA concentrations, the strong acidity of sulfonic groups reduced the degree of sulfate group dissociation, leading to a decline in doping efficiency. Full article

Wearable electronic devices have shown great application prospects in the fields of tactile sensing, electronic skin, and soft robots. However, the existing wearable electronic devices face limitations such as power supply challenges, lack of portability, and discomfort, which restrict their applications. The invention of triboelectric nanogenerators (TENGs) with dual functions of energy harvesting and sensing provides an innovative solution to address these issues. This study prepared a highly stretchable conductive hydrogel using doped conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a strain sensor, demonstrating high sensitivity (GF = 4.31), an ultra-wide sensing range (0–1690%), ultra-fast response speed (0.15 s), excellent durability, and repeatability. A high-performance triboelectric nanogenerator was constructed using the hydrogel as an electrode, achieving an output performance of up to 192 V. Furthermore, the TENG fixed in the hands, wrists, legs, and feet of the human body can be used as a wearable electronic device to monitor human motion, which is conducive to promoting the development of triboelectric nanogenerators based on conductive hydrogels in strain sensors and self-powered wearable devices. Full article

Hybrid organohalide perovskites have received considerable attention due to their exceptional photovoltaic (PV) conversion efficiencies in optoelectronic devices. In this study, we report the development of a highly sensitive, self-powered perovskite-based photovoltaic photodiode (PVPD) fabricated by incorporating a poly(amic acid)-polyimide (PAA-PI) copolymer as an interfacial layer between a methylammonium lead iodide (CH₃NH₃PbI₃, MAPbI₃) perovskite light-absorbing layer and a poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT: PSS) hole injection layer. The PAA-PI interfacial layer effectively suppresses carrier recombination at the interfaces, resulting in a high power conversion efficiency (PCE) of 11.8% compared to 10.4% in reference devices without an interfacial layer. Moreover, applying the PAA-PI interfacial layer to the MAPbI₃ PVPD significantly improves the photodiode performance, increasing the specific detectivity by 49 times to 7.82 × 10¹⁰ Jones compared to the corresponding results of reference devices without an interfacial layer. The PAA-PI-passivated MAPbI₃ PVPD also exhibits a wide linear dynamic range of ~103 dB and fast response times, with rise and decay times of 61 and 18 µs, respectively. The improved dynamic response of the PAA-PI-passivated MAPbI₃ PVPD enables effective weak-light detection, highlighting the potential of advanced interfacial engineering with PAA-PI interfacial layers in the development of high-performance, self-powered perovskite photovoltaic photodetectors for a wide range of optoelectronic applications. Full article

This study introduces a novel water-insoluble dispersant for coal water slurry (CWS), namely, a poly(sodium styrene sulfonate)-grafted SiO₂ nanoparticle (SiO₂-g-PSSNa). SiO₂-g-PSSNa was synthesized by combining the surface acylation reaction with surface-initiated atom transfer radical polymerization (SI-ATRP). Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), energy dispersive spectrometer (EDS), nuclear magnetic resonance spectroscopy (NMR) and thermogravimetric analysis (TGA) verified that SiO₂-g-PSSNa with the desired structure was successfully obtained. Afterwards, the performance of SiO₂-g-PSSNa as a dispersant in CWS preparation was evaluated. The results indicated that the optimal dosage of SiO₂-g-PSSNa was 0.3%. Compared to the famous commercial products, PSSNa and lignosulfonate (LS), SiO₂-g-PSSNa exhibits improved viscosity reduction performance. When SiO₂-g-PSSNa was used as the dispersant, the maximum coal loading of CWS was 64.2%, which was higher than LS (63.4%) and PSSNa (63.9%). All CWSs obtained in this study were pseudoplastic fluids and more consistent with the Herschel–Bulkley rheological model. The turbiscan stability index (TSI) of CWS prepared with SiO₂-g-PSSNa was 0.05, which was significantly lower than CWSs obtained from PSSNa (0.30) and LS (0.36). Therefore, SiO₂-g-PSSNa also exhibits excellent stability performance. This result was confirmed by rod penetration tests. The underlying mechanism was also clarified by various measurements, such as contact angle, zeta potential, EDS and low-field nuclear magnetic resonance spectra (low-field NMR). The results reveal that SiO₂-g-PSSNa can adsorbed onto the coal surface. SiO₂-g-PSSNa possesses a special branched structure, which bears a higher charge density as compared to linear ones with approximate chemical composition. As a result, coal particles adsorbed with SiO₂-g-PSSNa exhibit more electronegativity. With the enhancement of the electrostatic repulsive between coal particles, the apparent viscosity was lowered and the static stability was improved. This study demonstrated that solubility in water is not an essential factor in engineering the dispersant. Densely charged groups are probably more important. Full article

This study explores the layer-by-layer (LBL) modification of polyacrylonitrile (PAN) hollow fibers for effective Mg²⁺/Li⁺ separation. It employs an LBL method of surface modification using polyelectrolytes, specifically aiming to enhance ion selectivity and improve the efficiency of lithium extraction from brines or lithium battery wastes, which is critical for battery recycling and other industrial applications. The modification process involves coating the hydrolyzed PAN fibers with alternating layers of positively charged polyelectrolytes, such as poly(allylamine hydrochloride) (PAH), polyethyleneimine (PEI), or poly(diallyldimethylammonium chloride) (PDADMAC) and negatively charged polyelectrolytes, such as poly(styrene sulfonate) (PSS), to form polyelectrolyte multilayers (PEMs). This study evaluates the modified membranes in Mg²⁺ and Li⁺ salt solutions, demonstrating significant improvements in selectivity for Mg²⁺/Li⁺ separation. PAH was identified as the optimal positively charged polyelectrolyte. PAN hollow fibers modified with ten bilayers of PAH/PSS achieved rejection rates of 95.4% for Mg²⁺ ions and 34.8% for Li⁺ ions, and a permeance of 0.39 LMH/bar. This highlights the potential of LBL techniques for effectively addressing the challenges of ion separation across a variety of applications. Full article