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A deterministic, bright, room-temperature stable single-photon source (SPS) has been a major demand in the field of quantum photonics. Here, using computational and analytical techniques, we showed that the Mie-scattering moments of an all-dielectric cavity-cum-antenna help in shaping the spontaneous emission process of an embedded point-dipole emitter, the nanodiamond-based NV − and SiV color centers here. Our resonator-cum-antenna design comprises two top and bottom TiO 2 cylinders with a sandwiched polyvinyl alcohol (PVA) layer enclosing the nanodiamond crystal. The Cartesian multi-polar decomposition of the Mie-scattering moments of the sandwiched PVA layer (enclosing the dipole emitter) with subwavelength scale thickness showed strong electric-dipole (ED) resonance. This resulted in significant field confinement, making the PVA layer to act as a cavity, providing a Purcell enhancement of more than an order of magnitude for all dipole orientations. The top and bottom TiO 2 cylinders were observed to act as an antenna, and the far-field radiation pattern of the embedded dipole-emitter is controlled by the Mie-scattering moments of the TiO 2 cylinders. The radiation directionality along the vertical directions was found to be maximum at the Kerker point (electric dipole moment, ED = magnetic dipole moment), the collection efficiency (CE) being about 80%. For dipole emission coupled to the antenna, the quantum efficiency was observed to increase to a high value of 0.98 for nanodiamond NV − center, very close to an ideal case of purely radiative emission. Our scheme is shown to be universal and can be applied to any solid-state-based quantum emitters, for generating on-demand SPS for quantum-photonic applications. [ABSTRACT FROM AUTHOR]

We introduce a method utilizing single laser-generated cavitation bubbles to stimulate cellular mechanotransduction in dermal fibroblasts embedded within 3D hydrogels. We demonstrate that fibroblasts embedded in either amorphous or fibrillar hydrogels engage in Ca2+ signaling following exposure to an impulsive mechanical stimulus provided by a single 250 µm diameter laser-generated cavitation bubble. We find that the spatial extent of the cellular signaling is larger for cells embedded within a fibrous collagen hydrogel as compared to those embedded within an amorphous polyvinyl alcohol polymer (SLO-PVA) hydrogel. Additionally, for fibroblasts embedded in collagen, we find an increased range of cellular mechanosensitivity for cells that are polarized relative to the radial axis as compared to the circumferential axis. By contrast, fibroblasts embedded within SLO-PVA did not display orientation-dependent mechanosensitivity. Fibroblasts embedded in hydrogels and cultured in calcium-free media did not show cavitation-induced mechanotransduction; implicating calcium signaling based on transmembrane Ca2+ transport. This study demonstrates the utility of single laser-generated cavitation bubbles to provide local non-invasive impulsive mechanical stimuli within 3D hydrogel tissue models with concurrent imaging using optical microscopy. STATEMENT OF SIGNIFICANCE: Currently, there are limited methods for the non-invasive real-time assessment of cellular sensitivity to mechanical stimuli within 3D tissue scaffolds. We describe an original approach that utilizes a pulsed laser microbeam within a standard laser scanning microscope system to generate single cavitation bubbles to provide impulsive mechanostimulation to cells within 3D fibrillar and amorphous hydrogels. Using this technique, we measure the cellular mechanosensitivity of primary human dermal fibroblasts embedded in amorphous and fibrillar hydrogels, thereby providing a useful method to examine cellular mechanotransduction in 3D biomaterials. Moreover, the implementation of our method within a standard optical microscope makes it suitable for broad adoption by cellular mechanotransduction researchers and opens the possibility of high-throughput evaluation of biomaterials with respect to cellular mechanosignaling.

As a key component for the future high‐safety lithium batteries, solid polymer electrolyte (SPE) is gaining an attractive momentum toward large‐scale production due to their remarkable compatibility and processability with electrodes. Further, their excellent performance can be improved using the potential use of plasticizers. A deep eutectic solvent (DES) synthesized from choline chloride (ChCl) and citric acid monohydrate (CAM) demonstrates a promising plasticizer to design good SPE membranes along with poly (vinyl alcohol) (PVA). The changes in the surface chemistry of PVA‐based membranes, as determined by Fourier transform infrared (FTIR) spectroscopy, confirm the success of DES‐plasticizing effect, where detected by wavenumber shifting around main functional groups such as OH, CO, and COC. Following this, EIS characterization on electrical properties reveals the role of 30 wt% DES in improving the ionic conductivity, with the highest ionic conductivity equivalent to 4.66 × 10−4 S cm−1 and the crystallinity index as high as 41.09%. The presence of LiClO4 and DES significantly reduces mechanical performance, and glass transition of PVA‐based membranes, as characterized by tensile testing and differential thermal analysis/thermogravimetric analysis. Thus, the presence of DES in PVA and LiClO4 matrices could open another window for designing SPE with novel physicochemical properties. [ABSTRACT FROM AUTHOR]

[Display omitted] Marigold analogues micro flowers of tungsten oxide (WO 3) have been grown in thin film form through simple and cost-effective solution chemistry approach on stainless steel substrate. Aqueous precursor involving WO 4 - 2 ions agglomerated as self-sacrificing template growing initially into the nano-petal, followed by self-assembly; leading to marigold analogues micro flower surface architecture. This enthralling morphology motivated us not only to fabricate supercapacitive electrode but also to design complete solid-state supercapacitor devices in dual configurations: flexible pouch cell and coin cell. Interestingly, both devices even in symmetric configuration yields remarkable potential window of 1.82 V when sandwiched by gel inclusive of Li+ ions dispersed in non-conducting polyvinyl alcohol matrix. Solid-state flexible pouch cell and coin cell delivered specific capacitances of 103.98 ± 3.59 and 30.09 ± 1.03 F/g respectively at a scan rate of 5 mV/s. Assembled electrode, coin-cell and flexible pouch-cells have been well assessed in-depth through specific capacitances using cyclic voltammetry and galvanostatic charge discharge, diffusive and capacitive contributions, mechanical bending tests, electrochemical active surface area, and electrochemical impedance analysis. Practical applicability has been demonstrated for designed flexible pouch cell to run small fan and light emitting diode panel whereas coin cell to run light emitting diode panel. [ABSTRACT FROM AUTHOR]

[Display omitted] Spinel Li 4 Ti 5 O 12 (LTO), a zero-strain material, is a promising anode material for solid-state thin-film lithium-ion batteries (TFB). However, the preparation of high-performance Li 4 Ti 5 O 12 thin-film electrodes through facile methods remains a significant challenge. Herein, we present a novel approach to prepare a binder- and conductor-free porous Li 4 Ti 5 O 12 (P-LTO) thin-film. This approach polyvinyl alcohol (PVA)-assisted spray deposition and does not require the use of complex or expensive methods. Adding PVA to the precursor solution effectively prevents thin-film cracking during high-temperature annealing, enhances adhesion, and forms a highly interconnected porous structure. This unique structure shortens the lithium-ion diffusion pathways and facilitates electron transport. Therefore, P-LTO thin film electrodes demonstrate exceptional rate capacity of 104.1 mAh/g at a current density of 100C. In addition, the electrodes exhibit ultra-long cycle stability, retaining 80.9 % capacity after 10,000 cycles at 10C. This work offers a novel approach for the preparation of high-performance thin-film electrodes for TFBs. [ABSTRACT FROM AUTHOR]

This paper utilizes the reaction of phytic acid (PA) and urea (UM) in polyvinyl alcohol (PVA) solution to synthesize flame retardant gasses (CO2, NH3) for the preparation of PVA composite films containing flame retardant microbubbles. The flame retardancy of PVA composite films was assessed using methods including limiting oxygen index (LOI), vertical burning (UL 94), and cone calorimetry. The results indicated an increase in the LOI of the PVA composite film containing flame retardant microfoam from 20% to 30% compared with the pure PVA film, and that UL 94 reached VTM‐0. Furthermore, its peak exothermic rate and total exothermic amount were reduced by 36.25% and 38.92%, respectively, compared with the pure PVA film. The investigation of the flame‐retardant mechanism employed thermogravimetric‐infrared (TG‐IR), scanning electron microscopy (SEM), Raman spectroscopy, and infrared spectroscopy. The results demonstrate that the CO2 and NH3 flame retardant microbubbles within the composite film render it less ignitable at the initial stage, and that the internal UM of the composite film continues to decompose, releasing CO2 and NH3 upon heating. In addition, the acidic substances decomposed by PA during combustion promote the dehydration, cross‐linking, and cyclization of PVA, generating chemical structures such as POC, POP, and PO4 with enhanced thermal stability. This encourages the formation of a continuous, dense charcoal layer and impedes the transfer of oxygen and heat into the interior. [ABSTRACT FROM AUTHOR]

The characteristic of materials with special strength and toughness is distinguished by the uniform arrangement of their multi‐level structures, which is a key factor that significantly affects their mechanical behavior and overall performance. This work explores the challenges and potential solutions to enhance the mechanical properties of hydrogels through the construction of multi‐scale, multi‐layered ordered uniform structures. A novel approach termed macromolecular network uniformization (MNU) that utilizes rotation ice templates to freeze‐cast uniform polymer networks in hydrogels is proposed. By integrating this process with salt‐out densification, hydrogels with exceptional toughness exceeding 350 MJ m⁻3 in both x and y directions with super‐high tensile stress (20 MPa) and strain at break (3000%), are obtained. This research effectively addresses the inherent limitation of hydrogel materials, which are primarily composed of hydrophilic polymers, limiting their potential for functional diversity and enhanced performance. To overcome this, the expansion of the hydrogel matrix is demonstrated to include hydrophobic polymers such as polycaprolactone (PCL) and polyacrylonitrile (PAN), thanks to the high solubility of DMSO. The MNU technique effectively produces high‐performance hydrogels with enhanced mechanical properties, increasing substrate diversity and enabling the development of durable hydrogel materials for various applications. [ABSTRACT FROM AUTHOR]

Hydrogels show great potential in agriculture and other fields due to their excellent water absorption. However, traditional hydrogels are predominantly made from petroleum-based materials, which are difficult to degrade and pose environmental challenges. Additionally, traditional hydrogels exhibit inadequate mechanical properties, making the development of biodegradable hydrogels with high mechanical strength and cost-effectiveness a significant challenge. This study utilizes cassava starch as the primary framework, polyvinyl alcohol as the flexible soft segment, and crosslinks with epichlorohydrin to synthesize a novel biodegradable and cost-effective hydrogel. The hydrogel underwent modification through the incorporation of carboxylated nanofibers and sodium bicarbonate. The hydrogel's characteristics were assessed through Fourier infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, swelling examination, and compressive stress evaluation. The primary focus was placed on investigating the hydrogel's mechanical properties and its swelling behavior in aqueous solutions. The influence of nanofiber content on the hydrogel's properties was appraised. The integration of nanofibers significantly enhanced the compressive strength of the hydrogel, reaching an impressive 135.35 kPa, which is notably higher than the 33.88 kPa displayed by the conventional starch hydrogel. Simultaneously, when compared to the unaltered common starch hydrogel, the hydrogel fortified with nano-fibrils exhibited improvements in the swelling rate and thermal stability, exhibiting an increase of 20.54% and 12.20%, respectively. To address the rapid release rate of chlorine dioxide, the new hydrogel was dried, then separately absorbed sodium chlorite and citric acid, and subsequently stacked to create a binary solid slow-release chlorine dioxide system. The actual effect of the slow-release system on the preservation of fruits was tested using cherry tomatoes as experimental subjects. The results showed that the deterioration rate and vitamin C retention rate of cherry tomatoes were significantly improved under the action of the slow-release system. The loss of vitamin C in cherry tomatoes under the influence of the SSRCD hydrogel system was 37.73% lower than that observed in the control group. Due to its good mechanical properties and economy, this innovative hydrogel is not only suitable for applications in the field of fruit preservation but is also expected to be widely used in public health, medical and various other domains. [ABSTRACT FROM AUTHOR]

The charge neutrality point (CNP) is one of the essential parameters in the development of graphene field-effect transistors (GFETs). For GFET with an intrinsic graphene channel layer, the CNP is typically near-zero-volt gate voltage, implying that a well-balanced density of electrons and holes exists in the graphene channel layer. Fabricated GFET, however, typically exhibits CNP that is either positively or negatively shifted from the near-zero-volt gate voltage, implying that the graphene channel layer is unintentionally doped, leading to a unipolar GFET transfer characteristic. Furthermore, the CNP is also modulated in time, indicating that charges are dynamically induced in the graphene channel layer. In this work, understanding and mitigating the CNP shift were attempted by introducing passivation layers made of polyvinyl alcohol and polydimethylsiloxane onto the graphene channel layer. The CNP was found to be negatively shifted, recovered back to near-zero-volt gate voltage, and then positively shifted in time. By analyzing the charge density, carrier mobility, and correlation between the CNP and the charge density, it can be concluded that positive CNP shifts can be attributed to the charge trapping at the graphene/SiO2 interface. The negative CNP shift, on the other hand, is caused by dipole coupling between dipoles in the polymer layer and carriers on the surface of the graphene layer. By gaining a deeper understanding of the intricate mechanisms governing the CNP shifts, an ambiently stable GFET suitable for next-generation electronics could be realized. [ABSTRACT FROM AUTHOR]

Compared to other types of dressings, hydrogels are widely recognized as an optimal choice for wound care due to their superior biocompatibility and high water content. As a novel class of antibacterial materials, hydrogel wound dressings can effectively extend the duration of antibacterial activity and demonstrate promising potential in facilitating tissue regeneration and wound healing. A composite hydrogel (PCE) consisting of polyvinyl alcohol (PVA) and chitosan (CS), loaded with different mass fractions of ε-polylysine (ε-PL), was prepared using a cyclic freeze-thaw method. Subsequently, the surface morphology, thermal stability, swelling property, antibacterial property and cytotoxicity of PCE composite hydrogels were comprehensively discussed. The results showed that there was a hydrogen bond interaction among ε-PL, CS and PVA. The pore size of the composite hydrogel initially decreased and then increased with the increasing of ε-PL mass fraction. The addition of ε-PL improves the thermal stability of the PCE composite hydrogel. As the mass fraction of ε-PL increased, the swelling rate of the composite hydrogel showed a trend of first decreasing and then increasing, which correlated with the changes in pore size. It is worth noting that when the mass fraction of ε-PL reached 0.6%, the swelling rate of the hydrogel reached 651.7% after 24 h, indicating that the hydrogel had excellent swelling performance. This performance facilitates gas exchange, effectively absorbs wound exudate, maintains appropriate humidity conditions for wound healing, and promotes wound healing, and promotes overall recovery. Furthermore, the PCE hydrogel showed complete antibacterial activity against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Additionally, the PCE composite hydrogel exhibits good cell compatibility. The prepared PCE composite hydrogel has potential value in wound dressing applications. [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol/lithium chloride hydrogel (PVA/LiCl) is one of the most used electrolyte in supercapacitors. Increasing the ionic conductivity and operating temperature range of PVA/LiCl would greatly boost the electrochemical performance of supercapacitors and enhance the devices’ environmental adaptability. This is of great significance yet rarely concerned about in energy communities. In this work, SiO2 functionalized PVA/LiCl (PVA‐SiO2/LiCl) is experimentally realized with high ionic conductivity and wide operating temperature range. The spectroscopic and theoretical experiments prove that SiO2 significantly regulates cation solvation structure to promote cation‐anion pair dissociation and diminish coagulation of PVA chains, increasing ionic conductivity from 19.01 mS cm−1 of PVA/LiCl to 56.17 mS cm−1 of the new electrolyte. SiO2 can also prevent cation‐anion association as temperature decreases, and the abundant hydroxyl groups on the SiO2 and the stretched PVA chains tune hydrogen bonds among dipolar water molecules. They effectively expand the operating temperature range of PVA‐SiO2/LiCl. PVA‐SiO2/LiCl greatly boosts the electrochemical performance of MnO2‐based supercapacitor. The design concept developed here opens up a way toward high‐performance hydrogel electrolyte development. [ABSTRACT FROM AUTHOR]

Wound healing is often impaired in patients with diabetes. Mesenchymal stem cells (MSCs) and MSCs-derived nanovesicles (MNVs) hold promise as therapeutic agents for managing diabetic wounds. However, efficient delivery and controlled release of MNVs within these wounds are essential for maximizing therapeutic effectiveness. In this study, we developed a dual-responsive hydrogel designed to respond to elevated levels of glucose and reactive oxygen species. This hydrogel combines polyvinyl alcohol with phenylboronic acid-grafted chitosan, referred to as PBA-CP, while MNVs were produced by shearing MSCs through membranes with varying pore sizes. The composite PBA-CP/MNVs hydrogel significantly accelerated wound healing in a diabetic wound model by promoting epithelialization, dermal reconstruction, hair follicle formation, and angiogenesis. MNVs were readily taken up by keratinocytes, fibroblasts, and endothelial cells, stimulating their proliferation and migration. Altogether, the chitosan-based PBA-CP/MNVs composite hydrogel presents a promising therapeutic strategy for diabetic wound treatment. [Display omitted] • The dual repsonsive PBA-CP hydrogel enables effective delivery and controlled release of MNVs at diabetic wound sites • MNVs are efficiently endocytosed by skin cells in vitro and in vivo • PBA-CP/MNVs significantly promote diabetic wound healing [ABSTRACT FROM AUTHOR]

In this study, three polycarboxylic acids with varying numbers of carboxyl groups were employed to crosslink polyvinyl alcohol (PVA): malonic acid as a diacid (MA), citric acid as a triacid (CA), and 1,2,3,4-butane tetracarboxylic acid as a tetraacid (BTCA). The crosslinking abilities of these acids were compared using physical, chemical, mechanical, morphological, thermal, and swelling measurements to assess their impact on the physicochemical properties of the resulting films. Based on the degree of crosslinking, mechanical strength, and thermal stability, tetra acid demonstrated superior crosslinking performance compared to di and tri acids. The highest strength was observed in the tetra acid crosslinked film, which exhibited a 127% increase over neat PVA. Regarding thermal stability, the decomposition temperature followed the order of tetraacid (450 °C) > triacid (378 °C) > diacid (350 °C). However, in terms of swelling behavior, triacid-crosslinked film, i.e., P-CA, exhibited the highest swelling. Further, the tetra acid-crosslinked film exhibited the lowest crystallinity and a higher contact angle (104.9°) than diacid and triacid crosslinked films. Additionally, the crosslinked films displayed enhanced elasticity compared to pure PVA, with the elasticity order being diacid > triacid > tetraacid, possibly due to differences in available crosslinking sites among the crosslinkers. [ABSTRACT FROM AUTHOR]

Summary: This study aims to develop a novel active food packaging material from hybrid micro‐nanofibrous mats fabricated from gelatin (G)–chitosan (Ch)–polyvinyl alcohol (PVA)–Origanum elongatum essential oil (EO), (G‐Ch‐PVA‐EO) through electro‐blowing. The fibrous mats were characterised to assess their morphologies, shelf life efficiency, antimicrobial and antioxidant properties, surface‐wetting, and thermal, chemical, and physical interactions, among other factors. Results showed that the antioxidant activity was improved with the addition of EO, this enhancement is potentially linked to its rich content of phenolic components; carvacrol and P‐cymene. In addition, G‐Ch‐PVA‐EO showed higher firmness measurements compared to the control samples. Herein, low microbial counts were noted for both mesophilic aerobic bacteria (3.76 log CFU g−1) and yeast/mould (3.91 log CFU g−1) even at day 20. To conclude, the G‐Ch‐PVA‐EO microfibrous mat exhibits great promise in preserving the freshness of tomatoes. [ABSTRACT FROM AUTHOR]

Summary: The white button mushroom is a significant vegan food with a limited shelf‐life. To prolong the shelf‐life of mushrooms, certain treatment must be implemented. The current investigation is involved in the development of biocomposite film (BCF) by employing cellulose nano crystal (CNC), dispersed in a polyvinyl alcohol (PVA) matrix. The CNC extracted from aloe vera rind exhibited a sharp crystalline peak and rod‐shaped structures with a particle size of ~322.7 nm. Among the various concentrations of the CNC, incorporated in the BCF, the 8% CNC (BCF‐8%)‐loaded film showed the highest mechanical strength of ~166.73 MPa and a best crystallinity pattern. The study examined the synergistic impact of BCF along with neroli and palmarosa essential oil vapours, which effectively preserved the overall physiochemical properties and sensory characteristics of white button mushrooms for up to 8 days of storage. Hence, these innovative packaging systems are suitable substitute for the commercial food grade packaging to maintain the quality of mushrooms during postharvest storage. [ABSTRACT FROM AUTHOR]

In this study modified cellulose based adsorbent was prepared from Populus nigra plant, and used for elimination of metaldehyde (herbicide) from model waste water. The adsorbent was characterized through analytical technique such as FTIR, SEM, EDX and XRD for structural adsorption related parameters. The results of SEM showed the suitability of the material to be used as adsorbent and FTIR showed successful crosslinking of polyvinyl alcohol into cellulose structure. In order to get maximum reclamation benefits from adsorbent it was subjected to a number of tests evaluating the effect of metaldehyde concentration, sorbent dose, contact time, initial pH of solution and temperature. The maximum removal of 70 % was achieved under conditions of 80 mg/L metaldehyde concentration, 60 min contact time, pH of 8, 0.08 g sorbent dosage, and room temperature (25 °C). The Langmuir isotherm model with correlation coefficients of 0.9855 and maximum adsorption capacity recorded was 8.32 mg/g, while excellent agreement was shown by kinetic data with pseudo second order kinetic model with R2 = 0.9876. Thermodynamic study indicated enthalpy change (ΔH° = −129 kJ/mol) to be negative, entropy change (ΔS° = 161.7 j/mol) positive, and the Gibbs free energy (ΔG) as negative showing that the process to be exothermic and feasible/spontaneous with an increase of randomness at solid liquid interface. The finding indicated that modified cellulose could be used as an efficient adsorbent for removal of metaldehyde from model waste water. However, further validation with other pollutants will be helpful in checking reproducibility of the present findings. [ABSTRACT FROM AUTHOR]

The effects of steel, polyvinyl alcohol, polypropylene and glass fibre reinforcements on alkali-activated concrete (AAC) were investigated by conducting various mechanical strength tests. The fibre dosage was 0.1–0.3% by volume of AAC. Furthermore, the effects of acidic exposure on the strength of fibre-reinforced alkali-activated concretes (FRAACs) were examined by immersing samples in 10% v/v solutions of hydrogen chloride, sulfuric acid or nitric acid for 28 days. It was found that fibre additions improved the compressive and flexural strength by up to 13% and 27%, respectively, while the modulus of elasticity was significantly improved by up to 52%. Acid attack tests on AAC specimens demonstrated sulfuric acid to be highly detrimental to the mechanical and chemical properties of AACs. The strength loss in FRAAC after acidic exposure was up to 50% less than that of the plain AAC. The glass-fibre-reinforced AACs were found to be highly resistant to acid attack, whereas the steel-fibre-reinforced AACs had less resistance. These findings were further validated by scanning electron microscopy, X-ray diffraction and Fourier-transform infrared spectroscopy, which showed the changes in the microstructure of the specimens subjected to acidic environments. Overall, the fibre reinforcements improved the mechanical and durability properties of AACs. [ABSTRACT FROM AUTHOR]

• Ice particles were generated in aqueous solution with various solute concentration. • Effects of AFP and PVA on the prevention of the ice particle growth were evaluated. • AFP was more effective to prevent the ice particle growth than PVA. • Effects of AFP and PVA became weak in thick solute concentration solution. Ice slurry is a promising functional fluid with high thermal energy density and high heat transfer rate. However, large ice particles in the ice slurry can cause blocking of tubes during ice slurry flow. Therefore, it is preferable to use fine ice particles to prepare ice slurry in many fields. In this study, ice slurries were generated from supercooled solutions containing additives, such as anti-freeze protein and polyvinyl alcohol, to prevent the increase in the ice particle size in the formation process of the ice slurry. The concentration of the solute and amount of the additive were varied as experimental parameters, and the size of the ice particles was evaluated. The average area of the ice particles decreased with the addition of the additives. In particular, anti-freeze protein was effective for generating fine ice particles in the ice slurry. However, the effects of the additives became weaker for higher concentration of the solute, and the size of the ice particles was almost the same regardless of the concentration of the solute and the amount of the additive. Moreover, it was found that particular properties, such as the freezing-point depression, kinematic viscosity of the solution, and effective latent heat of fusion, did not affect the size of the ice particles in the ice slurry generation process. [ABSTRACT FROM AUTHOR]

This study presents a novel approach for environmentally friendly paint removal, focusing on the efficient removal of methylene blue from aqueous environments using iron nanoparticles embedded in polyvinyl alcohol nanofibers. Iron nanoparticles were synthesized via a green method employing green tea extract under optimized conditions and characterized by FESEM, DLS, TGA, DTG, EDS, FTIR, and XRD. The average size of synthesized iron nanoparticles was 22 nm. Two fabrication techniques were employed to embed the nanoparticles into polyvinyl alcohol nanofibers: electrospinning of a solution containing iron nanoparticles, and in situ synthesis of nanoparticles on the PVA nanofibers. Comparative analyses revealed superior methylene blue adsorption rates when nanoparticles were synthesized in situ on the nanofibers. Characterization techniques, including FESEM, XRD, and FTIR, confirmed the successful formation of nanoparticles on the nanofibers. Response surface method using central composite design (CCD) was performed to find the optimal removal conditions. Optimal removal (85%) occurred under adsorption conditions of pH 8.6, an initial methylene blue concentration of 30 mg/L, a nanofiber dose of 1.6 g/L, and a contact time of 100 min. Kinetic studies demonstrated a pseudo-second-order adsorption model, while Langmuir isotherm analysis indicated a maximum adsorption capacity of 24.509 mg/g. Thermodynamic analysis suggested the spontaneous and exothermic nature of the adsorption process. This composite membrane is an efficient and economical method for removal dye from wastewaters. [ABSTRACT FROM AUTHOR]

Maleated cassava starch (MCS)/poly (vinyl alcohol) (PVA)/kaolin clay (KC) nanocomposite films with high mechanical and barrier properties were prepared by a simple casting film. Based on the MCS/PVA matrix, the effects of KC content on the MCS/PVA/KC nanocomposite films were investigated. SEM results demonstrated that the MCS/PVA/KC nanocomposite films exhibited KC good dispersion in the polymer matrix. FTIR spectra showed that the molecular interactions in the MCS/PVA/KC films with higher PVA content enhanced. The maximum tensile strength and elongation at break for the MCS/PVA/KC at 6 and 5% KC composite films were 16 MPa and 530%, respectively. The MCS/PVA/KC composite was applied to extend the shelf life of the banana, and results showed that the good shelf life of the banana was accepted. The MCS/PVA/KC composite film is a promising material for high-barrier food packaging. [ABSTRACT FROM AUTHOR]

The flourishing environmental concerns have grabbed the attention of researchers developing environmentally supportive materials in various fields. A green approach was used to create biopolymer blend composites based on polyvinyl alcohol (PVA) and chitosan (CS) doped with various concentrations of grape seed (GS). Various analytical techniques, such as Fourier-transform infrared spectroscopy (FTIR), UV–visible (UV) spectra, field emission scanning electron microscope (FE-SEM) and differential scanning calorimetry (DSC) were used to evaluate the optical, structural and thermal properties of the prepared blend composites. The optical properties of blend composites were determined by UV spectroscopy and the findings revealed that absorption intensity increased with increasing GS, while bandgap energy decreased from 4.18 eV for pure blend to 2.91 eV for blend/15 wt% GS. The homogeneous distribution of GS particles in the biopolymer blend was identified with FE-SEM images. DSC results showed that increasing the GS content increased the glass transition temperature of the blend composites. The AC conductivity and dielectric constant were measured using the LCR meter. The conductivity rises with increasing frequency and dosage of GS, with the greatest conductivity obtained at 15 wt% loading. In comparison to a pure blend, it was discovered that the inclusion of 15 wt% GS enhanced the tensile strength by 50%, hardness by 17% and the reduction in elongation at break by 19 %. As a consequence, environmentally friendly PVA/CS/GS biopolymer blend composites with excellent mechanical, thermal, electrical, and dielectric parameters might be a viable green option for flexible electronic, electrochemical and energy storage devices. [ABSTRACT FROM AUTHOR]

This study developed a novel paper-based sensor for the simultaneous analysis of ascorbic acid (AA) and hydroquinone (HQ). The sensor utilized polyvinyl alcohol (PVA)-stabilized silver nanoparticles (AgNPs-PVA) as the reagent probe and PVA media acted as the filter for separation of the analytes. Polydimethylsiloxane (PDMS) and ethanol serve as the stationary phase and eluent, respectively, exploiting the differences in analyte reactions and solubility to achieve their separation on the filter paper. The circular sensor's central zone was AA's detection area, while HQ was detected in the outer ring region. AA induced an immediate color change in the test kit, whereas HQ required a 20-minute elution with ethanol followed by colorimetric analysis. All analytes exhibited relative standard deviations of repeatability and reproducibility below 2.7% and 9.5%, respectively. Under optimal conditions, the linear detection range for HQ was 0.2-2.0 mg⋅L− 1, while AA was 0.1-2.0 mg⋅L− 1. The detection limit was determined to be 0.05 mg⋅L− 1 for AA and 0.1 mg⋅L− 1 for HQ. The recoveries of AA and HQ in cosmetic cream samples ranged from 80 to 110%. The accuracy of the sensor's measurements was further validated by comparison with the HPLC-DAD method. [ABSTRACT FROM AUTHOR]

A series of biodegradable colorimetric films were prepared by using chitosan and polyvinyl alcohol as matrix, in which, the weight ratio of chitosan: Polyvinyl alcohol was 100: 0, 80: 20, 50: 50, 20: 80, or 0: 100, with addition of 10% (w/w, relative to chitosan) anthocyanins extracted from purple tomatoes (purple tomatoes anthocyanin) as pigment. The aim of this study was to observe the effect of weight ratio (chitosan: Polyvinyl alcohol) on the mechanical properties, contact angle, swelling rate, pH sensitivity, antioxidant properties of chitosan-polyvinyl alcohol/purple tomatoes anthocyanins films, and the antibacterial activity of films produced for pork packaging. In addition, the films as a smart colorimetric indicator for monitoring the freshness of pork was investigated. The results showed that as the ratio of chitosan to polyvinyl alcohol decreases, the elongation at break, hydrophilicity, and swelling rate of the films increased especially from 16.5% to 174.2% for elongation at break and 93.0° to 53.8° for water contact angle, however, the tensile strength decreased from 67.3 to 24.7 MPa. With decreasing of chitosan: Polyvinyl alcohol, the antibacterial activity on pork was decreased, and the antioxidant properties of films increased first then decreased. Fourier transform infrared spectroscopy indicated there were interactions among chitosan, polyvinyl alcohol, and purple tomatoes anthocyanins. The color response of films was depended on pH, as well as the immersion time. The longer immersion resulted in a more pronounced color change. The color changed from purplish red (pH 2–4) to green (pH 5–10) to yellow (pH 10–12). In monitoring the freshness of pork, the film showed a nice visual color change, indicating a potential application in smart packaging. These bio-based materials may be useful alternatives to synthetic plastics for food applications such as active and smart packaging, thereby improving the environmental friendliness and sustainability of the food supply. [ABSTRACT FROM AUTHOR]

In our research described here, a strong acid oxidizing agent was selected to modify the surface of carbon black (CB) to obtain oxidized carbon black (OCB) particles. These OCB particles were then subjected to an ionic bonding reaction with alkaline amine groups present on the surface of octadecylamine polyoxyethylene ether (AC1830) in the form of a paste, resulting in the production of polyether amine-modified oxidized carbon black particles (A-CB). FTIR confirmed the successful production of the A-CB particles. The PVA composite films were prepared using the casting method with varying amounts of A-CB as filler and PVA as the matrix. The films were then analyzed using tensile, scanning electron microscopy, dynamic thermo-mechanical analysis, DSC, and water absorption testing. The results showed that the tensile strength was highest at 3% A-CB, reaching 154.85 MPa. A-CB was well dispersed in PVA at low contents (1% and 3%). The loss modulus, energy storage modulus, crystallinity, and crystallization rate of the A-CB/PVA films improved compared to PVA films. Additionally, the issue of excessive water absorption in A-CB/PVA has been improved. [ABSTRACT FROM AUTHOR]

Hydrogel‐based flexible strain sensors have an enormous potential for applications in wearable electronics, but currently, realizing excellent mechanical properties and electrical conductivity of sensors is difficult. In this work, polyvinyl alcohol (PVA) hydrogels were augmented with positively charged silk nanofibers (PCSNF) and PEDOT:PSS, and the resultant PVA‐PEDOT:PSS‐PCSNF hydrogel fabric showed remarkable mechanical properties (4.38 MPa) and elevated electrical conductivity. The presence of ethylene glycol (EG) in the hydrogel fabric imparts antifreezing properties and sustains electrical conductivity even at frigid temperatures (−18°C). In addition, EG contributes to the improvement of the electrical conductivity of PEDOT:PSS. This PVA‐PEDOT:PSS‐PCSNF hydrogel fabric can be used as a precise and reliable strain sensor for detecting diverse human motions and facial expressions. Significantly, the PVA‐PEDOT:PSS‐PCSNF hydrogel fabric strain sensor exhibits a gauge factor of 1.02 and exceptional durability, withstanding 400 elbow bends. This study introduces an innovative method for creating high‐performance and resilient hydrogel‐based flexible sensors. [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol (PVA) and potato starch‐based porous hydrogels have been fabricated and studied for their wettability. The starting material was crosslinked by glutaraldehyde performed via co‐polymerization reaction at room temperature and low temperature (freeze–thaw). The gels were characterized by Fourier transform infrared (FT‐IR), field emission scanning electron microscope (FE‐SEM), thermogravimetric (TG), and powder X‐ray diffraction (PXRD) analysis. The wetting studies of the gels were evaluated at ambient and submerged conditions by considering both oil and water drops as probe liquids. The gels tend to absorb oil and water in air, however, water‐wet gels demonstrated a very high oil contact angle (>150°). The gels demonstrated superoleophobicity, and the underwater oil CA >172° as the concentration (wt%) of PVA was increased in the gels. Overall, the freeze–thaw gels demonstrated higher underwater oil CA, however, both (room temperature and freeze–thaw fabricated) gels demonstrated similar affinity for under‐oil–water absorption and separation. The hydrogel can retain water easily and thus remove water (even dye dissolved in water) with high separation efficiency and recyclability. [ABSTRACT FROM AUTHOR]

In this study, the crosslinking agent citric acid (CA) is added to liquid glucose (LG)-polyvinyl alcohol (PVA) blend-based wood adhesives to improve their mechanical and thermal properties. The effect of crosslinking has been investigated using various analytical techniques, including viscosity, water contact angle, differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). Several variables were investigated for their effects on performance characteristics, including glass transition temperature, pencil hardness, and tensile strength. Increasing the amount of CA and the content of LG were among these factors. The crosslinked blend-based films increased in pencil hardness value and showed less hydrophilic behavior in the water contact angle test. It is expected that nucleophilic hydroxyl groups in LG and PVA will react with free carboxylic groups to form crosslinks. By analysing FTIR spectra, it has been demonstrated that CA and the LG-PVA mixture interact. After 24 h of bonding for two distinct ratios of PVA to LG (i.e., 25:5 and 20:10), the lap shear bond strength for the wood substrates bonded with the modified blend increased by 250% and 263% for 0.3 wt% CA, respectively. Blends with 0.5 and 0.7 weight% CA showed a predominately plasticizing tendency because CA that has not been reacted acts as an external plasticizer. The glass transition temperature (Tg) and increase in viscosity were indicators of the reaction's consequences due to the acidic pH. The newly developed crosslinked LG-PVA blend-based wood adhesive showed better mechanical and water resistance properties when compared to conventional LG-PVA blend-based wood adhesives. [ABSTRACT FROM AUTHOR]

The rise of flexible and wearable electronics has spurred advancements in printed, flexible micro-supercapacitors for energy storage. This study presents the fabrication of flexible micro-supercapacitors using a novel nanocomposite of tin dioxide grown on layered reduced graphene oxide through one-pot in situ synthesis. The conductive functional ink, formulated by mixing the nanocomposite, is effectively utilized in screen-printing technology. The resulting micro-supercapacitors, particularly the SG-1 variant, demonstrate impressive electrochemical performance. The nanocomposites show exceptional versatility across various electrolytes, including alkaline, acidic, and quasi-gel electrolytes with a polyvinyl alcohol matrix infused with potassium hydroxide. An in-depth comparison of their efficacy in these electrolytes highlights the most suitable configurations for optimal performance. At a scan rate of 5 mV s−1, SG-1 achieves areal capacitances of 148.7 mF cm−2 and 87.7 mF cm−2 in the 1 M KOH and polyvinyl alcohol infused with 1 M KOH quasi-gel electrolyte. Additionally, SG-1 in the gel electrolyte demonstrates remarkable energy density of 11.7 mWh cm−2 at power density of 490 mW cm−2. Notably, the fabricated micro-supercapacitors exhibit excellent capacitive retention of 89.5% even after undergoing 5000 cycles of charge–discharge, underscoring their robustness and long-term stability for practical applications in flexible and wearable electronics. [ABSTRACT FROM AUTHOR]

Copyright of Baghdad Science Journal is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The work aims to probe the chances of utilizing the waste of pomegranate peel powder as a filler material alongside the polymer matrix. PVA is used as a polymer matrix in this study and the improvisation of its properties are the main objective by utilizing the pomegranate peel powder. By solution casting method, PVA/PP biocomposite films were prepared with varying weight % (0%, 5%, 10%, 15%, and 20%) of pomegranate peel powder and are examined with FTIR, XRD, morphological studies, thermal analysis, tensile property, antibacterial test, and degradation test. The biodegradable films' tensile strength was discovered to be 18.5 MPa, a 35% increase over films devoid of essential oil. The use of essential oil improved the thermal stability as well; the beginning degradation temperature increased by 40% to 210°C. Additionally, antimicrobial tests showed a 92% decrease in bacterial growth, demonstrating the essential oil's effectiveness as an antibacterial agent. In order to evaluate the barrier qualities of the films, water vapor permeability was tested. It was discovered that the water vapor transfer rate was 2.3 g/m2/day, demonstrating remarkable resistance to moisture permeability. The aforementioned tests indicate that the use of pomegranate peel powder and PVA in biocomposite films results in improved biodegradation, as well as antibacterial activity, and that can be utilized in various eco-friendly applications. In the same way, they show improved tensile as well as thermal properties which suggest the utilization as packaging materials. [ABSTRACT FROM AUTHOR]

In this study, a film was prepared from polyvinyl alcohol (PVA) and zinc oxide (ZnO) nanoparticles (nano-ZnO) via the casting method. Nanoparticles were added to PVA biopolymer to create reinforced biocomposite films with different loading contents (2, 4, and 6 wt.%), and they were tested by performing the following assays: the FTIR test, the antibacterial, soil burial test, DSC, AFM, and SEM. The results showed an improvement of the membranes in the antibacterial properties for both Escherichia coli (E. coli, Gram-negative) and Staphylococcus aureus (S. aureus, Gram-positive) when nano-ZnO was added. The biodegradation through weight loss was observed for all samples, and the results showed that the weight loss increased with the increase in ZnO nanoparticle content from 2% to 6% wt. The DSC results showed that the addition of ZnO led to an increase in Tg, and increasing the degree of glass transition led to an increase in the degradation rate. In the FTIR results, only physical interference was observed; no chemical interference was evident. The AFM results showed some agglomerations of nano-ZnO in the PVA matrix led to an increase in the surface roughness of the PVA/nano-ZnO film. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Donghua University (Natural Science Edition) is the property of Journal of Donghua University (Natural Science) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hydrogels exhibit promising applications, particularly due to their high water content and excellent biocompatibility. Despite notable progress in hydrogel technology, the concurrent enhancement of water content, mechanical strength, and low friction poses substantial challenges to practical utilization. In this study, employing molecular and network design guided based on multiple synergistic enhancement mechanisms, we have developed a robust polyvinyl alcohol (PVA)–polyacrylic acid (PAA)–polyacrylamide (PAAm) three-network (TN) hydrogel exhibiting high water content, enhanced strength, low friction, and fatigue resistance. The hydrogel manifests a water content of 63.7%, compression strength of 6.3 MPa, compression modulus of 2.68 MPa, tensile strength reaching 7.3 MPa, and a tensile modulus of 10.27 MPa. Remarkably, even after one million cycles of dynamic loading, the hydrogel exhibits no signs of fatigue failure, with a minimal strain difference of only 1.15%. Furthermore, it boasts a low sliding coefficient of friction (COF) of 0.043 and excellent biocompatibility. This advancement extends the applications of hydrogels in emerging fields within biomedicine and soft bio-devices, including load-bearing artificial tissues, artificial blood vessels, tissue scaffolds, robust hydrogel coatings for medical devices, and joint parts of soft robots. [ABSTRACT FROM AUTHOR]

In this paper, the Optimization Design and properties of polyvinyl alcohol (PVA)/gelatin (GEL) nanofibers were studied. Different mass fractions of PVA (4, 5, 6 and 7 wt%), GEL (1, 2, 3 and 4 wt%), different spinning distances (8, 15, 22 and 29 cm), different voltages (10, 17, 24 and 31 kV), and different spinning speeds (0.1, 0.2, 0.3 and 0.4 mL) were designed into five factors and four levels by orthogonal experiments. The conductivity and viscosity of the mixed solution was tested. The PVA/GEL nanofibers were prepared by electrospinning and the morphology of composite nanofibers was observed under electron microscope. Finally, the PVA/GEL nanofiber film was tested by infrared spectroscopy and X-ray diffraction. The results showed that the infrared spectral groups and X-ray diffraction angles of nanofibers with different PVA/GEL ratios have little change. PVA/GEL nanofiber materials have great application potential in the field of biomedicine. [ABSTRACT FROM AUTHOR]

Due to the atomic thickness of 2D MoS2 film, the electronic structure is easily tunable by electric field and exhibits abundant property. However, due to the limit capacitance of inorganic dielectric, the tunability is still not well exhibited. Herein, a MoS2 phototransistor with large tunability driven by ion‐gel film is fabricated. To improve the interface and reduce the dark current, the passivation layer is used to hinder the leakage current. With the passivation layer, there will be a specific barrier height on the interface of metal electrodes and ion‐gel membrane. Under effect of the PVA (polyvinyl alcohol) passivation layer, the current on/off radio can reach 107 and the mobility can reach 6.54 cm2/(Vs) superior to the one without passivation layer. There is an abnormal behavior in the transistor including positive and negative photoresponse due to the coupling of the photogating effect and the adsorption of negative ion. The photoresponsivity can increase by 29 times which can reach 603.48 A W−1 at 400 nm illumination. Furthermore, the flexible transistor based on ion‐gel can be demonstrated and it found that the transistor still has a considerable photoresponse with strain of 0.49%. This work provides a new solution for flexible wearable electronic and photoelectronic detection field. [ABSTRACT FROM AUTHOR]

Multi‐component doping has become an effective way to achieve efficient room‐temperature phosphorescence. In this paper, green phosphorescence emission from coumarin derivatives, i.e., coumarin‐3‐carboxylic acid (CCA) and coumarin‐3‐carboxylic ester (CEt) are activated by doping them into polyvinyl alcohol (PVA) matrix (two component doping). Then, a series of metal salts (Ca2+, Al3+, Mn2+, and Zn2+) are added as the third component to construct three‐component doping system, with the aim to further improve the phosphorescence properties of the polymer films. Among them, CaCl2 can significantly increase the emission intensity (9.2 times), prolong the phosphorescence lifetime (up to 361 ms), and increase the phosphorescence quantum yield (from 1.02% to 9.19%). The results indicated that RTP emission can be activated by inhibiting the non‐radiative transition of coumarin derivatives embedded in the rigid PVA matrix. RTP performance can be further enhanced relying on the coordination effect between the coumarin guests and the metal salts. This study provides a simple and effective three‐component doping method for boosting polymer film‐based phosphorescence performance. [ABSTRACT FROM AUTHOR]

A series of polyaniline (PANI) nanofibers were prepared as conductive fillers. A polyvinyl alcohol (PVA)/agarose (AG) double network hydrogel was used as a flexible substrate. A PANI/PVA/AG conductive hydrogel was prepared via in situ polymerization of polyaniline nanofibers in a PVA/AG double network hydrogel. The electrochemical performance of the PANI/PVA/AG hydrogel electrode material was linked to the fiber morphology of polyaniline. The doping of polyaniline with 0.020 mol L−1 citric acid demonstrated superior fiber morphology compared to doping with other citric acid concentrations, achieving fiber ratios of 80%. The specific capacitance of the PANI/PVA/AG hydrogel electrode materials doped with 0.020 mol L−1 citric acid was 285 mF cm−2, while the conductivity was 7.1 S m−1. The doping of polyaniline with 0.5 mol L−1 hydrochloric acid demonstrated superior fiber morphology compared to doping with other hydrochloric acid concentrations, achieving fiber ratios of 65%. The specific capacitance of PANI/PVA/AG hydrogel electrode materials doped with 0.5 mol L−1 hydrochloric acid was 249 mF cm−2, while their conductivity was 7.6 S m−1. After 500 cycles of charge–discharge, the specific capacitance retention of the material was 73%. Photosensitivity tests indicated that the hydrogel exhibited high sensitivity to shorter wavelengths of blue light (460 nm) and ultraviolet light (380 nm). The hydrogel sensor possessed high sensitivity to strain in the range of 0–120%. Gauge factors (GF) of the hydrogel strain sensor were 1.280, 2.141, 1.907, and 1.261 for strain ranges of 0–30%, 30–60%, 60–90%, and 90–120%, respectively. Cyclic strain tensile tests indicated that the relative resistance change rate (ΔR/R0) of the hydrogel sensor demonstrated a certain degree of repeatability and stability within the range of 0–100%. Thus, the hydrogel sensor is reliable and stable in the signal transmission process of detecting human movements as a flexible strain sensor. These results suggest that the PANI/PVA/AG conductive hydrogel is a multifunctional composite with good electrochemical storage performance, photosensitivity, and strain sensitivity that can be used in applications such as supercapacitors, flexible sensors and electronic wearable devices. [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol (PVA) and zinc oxide (ZnO) nanocomposite films were synthesized and characterized in this study through a spray method with varying concentration of ZnO nanoparticles incorporated within the polymer. The XRD patterns exhibit significant peak broadening, indicative of a high‐purity wurtzite hexagonal structure in the nanoparticles, and exhibit notably higher intensity peaks after argon (Ar) plasma treatment which may be due to increase in crystallinity of the ZnO nanoparticles. The AFM analysis of PVA samples with varying ZnO nanoparticle concentrations reveals a clear increase in surface roughness as the ZnO content rises. The mean roughness (Sa) increases from 0.90598 nm at 0 wt % ZnO to 1.18807 nm, 1.46771 nm, 1.84988 nm, and 2.60792 nm at 1 wt %, 3 wt %, 5 wt %, and 10 wt % ZnO, respectively. FESEM images show the change in morphology with the addition of ZnO nanoparticles where the round and clustered particles noted indicate a clustered distribution on the surface, and after plasma treatment, the surface gets etched or eroded. These films were then subjected to DC glow discharge plasma with Ar gases for functioning minutes starting from 15 min to 25 min. In order to study the change in the surface chemistry of PVA and PVA–ZnO nanocomposite films, the FTIR spectroscopy test was conducted. In the FTIR spectra, typical absorption bands of monoclinic phase of nano‐ZnO were present and thus it can be said that Ar plasma treatment could slightly affect the chemical functional groups present on the surface. For plasma‐treated materials, UV‐Vis absorption spectra indicated that optical absorption increased with ZnO concentration and shifted to longer wavelengths. The calculated refractive index values for the samples, which fall within the visible range of the spectrum, ranged from 1.356 to 1.891. The extinction coefficient was found to increase for both untreated and Ar plasma–treated samples with longer treatment times. This work focuses on application of plasma technology, namely, DC glow discharge plasma, for surface treatment that can be a promising technology to improve properties of material. [ABSTRACT FROM AUTHOR]

Binders used in binder jetting often pose health and environmental risks during processing and post processing operations. The print-heads which are used to deposit binder selectively on the feedstock are prone to clogging, despite the trend of print-heads being highly customised to suit different kinds of binders. These factors often hide the advantages of binder jetting as an additive manufacturing process, especially its scalability and its faster printing rates in comparison to powder bed fusion methods. The work presented here takes a step back and focuses on the development of an aqueous, polyvinyl alcohol (PVA)-based liquid binder that is easy to manufacture and store, safe to handle, and can be reliably jetted to print parts. The feedstock considered was Inconel 718, a nickel-based super alloy which can be effectively processed by binder jetting without niobium segregation. PVA was added to the Inconel 718 powder in dry, granular form to manufacture a modified feedstock. The study also investigated the role of molecular weight of the PVA used, sintering environments and post-processing methods like hot isostatic pressing (HIP) on process responses like part densification, tensile strength, and hardness. Three different types of PVA were chosen which had molecular weights 10,000 g/mol (low molecular weight or LMW), 26,000 g/mol (medium molecular weight or MMW), and 84,000 g/mol (high molecular weight or HMW). The compatibility of the liquid, aqueous PVA-based binders with virgin Inconel 718 was examined by measuring the contact angle. The liquid, aqueous binder having MMW PVA reported better wetting with the Inconel 718 powder with a wetting angle of 26.6 which was lower than the wetting angle of 42.4°, seen in case of a commercial resin-based binder. The green strength reported by the MMW PVA liquid binder was 220 kPa which was higher than the other two PVA-based liquid binders. Green parts, upon successful printing, were sintered at 1260 °C. It was observed that a part printed using MMW PVA had a densification of 96.16% when sintered in 99.98% by volume argon gas, which increased to 98.96% after undergoing HIP. The same part reported a densification of 88.69% when sintered in a 95% by volume N2 and 5% by volume H2 gaseous environment, which was later attributed to the uptake of nitrogen by the chromium present in Inconel 718, which prevented necking between particles. Tensile specimens printed using MMW PVA, sintered in a 99.98% argon environment, showed the highest ultimate tensile strength of 220 MPa, which increased to 1010 MPa after the HIP process, which can be compared to commercially available Inconel 718. [ABSTRACT FROM AUTHOR]

Amorphous polymer‐based materials combining high optical transparency, mechanical flexibility, and the potential for low‐cost scalability and processing, are attractive in the vibrant field of ultralong organic phosphorescence (UOP). However, developing amorphous polymer‐based UOP materials with high quantum efficiency (ФP) remains a formidable challenge because the inherently loose polymer networks lead to the violent non‐radiative transition and quenching processes of triplet excitons. Herein, a series of amorphous polymer‐based UOP materials are fabricated by doping organic phosphors (SA, DA, and TA) composed of triphenylamine units modified with different numbers of carboxyl groups into polyvinyl alcohol (PVA) matrix. These experimental and computational results indicate that the resulting polymer films (SA/PVA, DA/PVA, and TA/PVA) exhibit the gradually enhanced UOP, which is attributed to the increased intermolecular hydrogen‐bonded interactions, enabling incremental repulsive interactions between the isolated chromophores and PVA matrix, resulting in the reduced dissipation of triplet excitons through a non‐radiative transition. Remarkably, TA/PVA has an optimal ФP of up to 77.5%, which is a record ФP among the reported heavy‐atom‐free amorphous polymer‐based UOP materials. Given the bright afterglow emission and solution‐processable properties, the promise of transparent, flexible, and large‐area paints for display and illumination are demonstrated. This study will provide a design strategy to enhance the quantum efficiency of amorphous phosphorescent materials, showing great promise in flexible electronics. [ABSTRACT FROM AUTHOR]

In this study, nano‐magnesium oxide (MgO) was modified with surfactants sodium polyacrylate, polyvinyl alcohol (PVA) and polyethylene glycol (PEG) based on the agglomeration problem of nano‐MgO in cement. The surfactant PEG with the best modification effect was selected to modify nano‐MgO and synergize with the dispersing effect and early‐strengthening effect of triethanolamine (TEA) to prepare a new type of composite cementitious sealing material with high early compressive strength and good fluidity. The optimal ratio of the mass fraction of the composite early‐strengthening agent was determined by the response surface method: 0.02% PEG + 2% nano‐MgO + 0.04% TEA. The effects of the composite early‐strengthening agent on the cementitious sealing material were investigated by the compressive strength, fluidity, setting time, X‐ray diffraction experiments (XRD), thermogravimetric (TG‐DSC), scanning electron microscopy (SEM), etc. The effect of the composite early‐strengthening agent on the cementitious sealing material was also investigated by the response surface method. The compressive strength of the composite cement specimens at 1d, 3d, and 7d was increased by 92.59%, 35.50%, and 47.73% respectively compared to the blank group. In comparison to the control group, the flowability increased by 31.96%, and the initial and final setting time was shortened to 377 min and 394 min, respectively. [ABSTRACT FROM AUTHOR]

Highlights Ultra‐high molecular weight polyethylene (UHMWPE) is commonly used with many layers to realize protection and this can greatly benefit from advancements in fabric mechanical properties. This research introduces an innovative approach to crafting a composite felt, leveraging UHMWPE fabric, carbon nanotubes (CNTs), shear thickening fluid (STF), and polyvinyl alcohol (PVA) binder through a spray technique. The method results in a fabric with exceptional tensile strength and anti‐impact characteristics. Observations during the fabrication process reveal profound surface morphology alterations, showcasing an intricate layering of PVA binder, CNTs, and STF that seamlessly encapsulates each component of the STF/CNTs/UHMWPE system. The tensile strength and anti‐impact properties including punch residual velocity and energy absorbed are 564.0 ± 12.4 MPa, 1.537 ± 0.032 m/s and 22.952 ± 1.158 J in 12 ms, increased by 143.3%, 24.3% and 193.3%, respectively, compared to neat UHMWPE. This substantial performance uplift is attributed to multiple factors: the reinforcing friction between fibers/yarns fostered by the PVA binder and the full or partial embedding of CNTs, the additional reinforcing strength imparted by the CNTs matrix, and the dynamic viscosity enhancement of STF under impact forces. Anti‐impact felt was prepared by spraying PVA, CNTs, and STF onto UHMWPE. The tensile strength of anti‐impact felt was improved by 143.3%. The energy absorbed and impact depth was raised by 193.3%. The enhanced friction between fibers is caused by PVA and CNTs. The strength of CNTs and increased viscosity of STF under impact are notable. [ABSTRACT FROM AUTHOR]

Ionic conductive hydrogels are widely used in many applications such as electrochemical energy storage, flexible electronic devices, and catalyst transistors due to their excellent ionic conductivity as well as chemical stability. However, the fragile mechanical properties and the lack of shaping methods severely limit their further applications. Herein, an ionic conductive composite hydrogel with reinforced mechanical properties is demonstrated that can be rapidly 3D printed using digital light processing technology. By using both γ‐methacryloxypropyltrimethoxysilane moderately modified attapulgite rigid particle and polyvinyl alcohol (PVA) semicrystal dual‐network reinforcement, the mechanically robust and highly conductive N,N,N‐trimethylethanaminium‐chloride‐based hydrogels are obtained, demonstrating a 5 times higher tensile strength than the initial one due to the turning and orienting of the attapulgite as well as the robust PVA secondary network. Furthermore, encapsulation strategy is used to avoid the dehydration of hydrogel, and strain sensors that exceed the strain limit of the hydrogel are fabricated through structural design. This work provides a reference for attapulgite‐reinforced hydrogel in biosensing. [ABSTRACT FROM AUTHOR]

As family members of polycyclic aromatic hydrocarbons, compound anthracene (Ant) and phenanthrene (Phe) as isomers are widely used in organic optical materials and electronic materials. But their photochemical and physical properties are very different. In this work, the room temperature phosphorescence (RTP) properties of PVA−B‐Ant and PVA−B‐Phe are discussed carefully which are prepared by B−O click reaction through polyvinyl alcohol (PVA) with 9‐anthraceneboronic acid (B‐Ant) and 9‐phenanthrenylboronic acid (B‐Phe), respectively. PVA−B‐Phe 1 % film exhibits excellent fluorescence (FL) emission at 374 nm and RTP emission at 523 nm with green afterglow and around 1.9 s phosphorescence lifetime. However, PVA−B‐Ant 1 % film only shows strong blue FL emission at 414 nm, and the emission intensity decreases seriously with the extension of irradiation time. Experimental and theoretical calculations results suggest that the photodimer of Ant which is formed in PVA matrix under the UV light irradiation would be competitive with the process of RTP emission. This work demonstrates that the RTP properties of organic molecules might be probably affected by the photostability of the organic phosphor under UV irradiation. [ABSTRACT FROM AUTHOR]

In this work, an inter-crosslinked network membrane of polyvinyl alcohol (PVA) and chitosan (CS) and SnO2 nanocparticle-incorporated nanocomposite membranes of PVA and CS (PVA/CS/SnO2) having enhanced proton conductivity have been fabricated by the solvent-casting method. SnO2 nanoparticles are synthesized using a sol–gel method, and their crystalline nature, morphology and particle size are examined using X-ray diffraction analysis, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM), and the characteristics of the membranes such as proton conductivity (PC), swelling ratio (SR), porosity, water uptake (WU), oxidative stability (OS), ion exchange capacity (IEC), and other common physiochemical characteristics were also assessed for both the bare and SnO2 nanoparticles loaded PVA/CS films. At room temperature (RT), the highest IEC rate of 0.94 mmol g−1 and proton conductivity value of 6.3 × 10−3 S cm−1 for PVA/CS/SnO2 were observed when 3 weight percent SnO2 nanoparticles were added to PVA/CS. Additionally, the PVA/CS/SnO2 compsoite membrane loaded with 3 wt% SnO2 NPs, at 80°C for 10 hours, showed outstanding OS with 12.3% degradation towards the Fenton reagent under anhydrous conditions. As this work combines the upgrading of commodity polymers, like PVA, to be employed in fuel cell devices, the nanocomposite membranes created in this work showed notable properties that may find a large place in the future fuel cell industry. [ABSTRACT FROM AUTHOR]

Janus particles are a class of materials that exhibit both surface morphology and chemical properties with asymmetry. However, at present, precise control over the structure and composition of Janus particles still faces numerous challenges. Conventional seed emulsion polymerization methods require heating to induce phase separation after seed swelling, leading to extended reaction periods. In light of this, we propose a novel photo-induced seed swelling polymerization approach. This method employs non-crosslinked polyglycerol methacrylate (poly(GMA)) as seed particles, utilizing 4-vinylpyridine (4-VP) as the functional monomer and divinylbenzene (DVB) as the cross-linker. The aqueous phase consists of polyvinyl alcohol (PVA) and sodium dodecyl sulfate (SDS), with 2,2-dimethoxy-2-phenylacetophenone (DMPA) as the photo-initiator. By adjusting parameters such as seed quantity, type of porogen, and porogen volume ratio, diverse morphologies including octopus-like, jellyfish-like, snowman-like, and half raspberry-like Janus particles are successfully synthesized. Subsequently, Janus carbon particles are obtained through calcination and employed as anode materials in lithium-ion batteries. The electrochemical performance of Janus carbon particles is assessed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), rate capability tests, constant current charge–discharge measurements, and cycling performance evaluation. These tests indicate the excellent electrochemical properties of the material. Our research provides a valuable strategy for creating Janus carbon particles with controlled morphologies. [ABSTRACT FROM AUTHOR]

Mn4+-activated luminescent materials exhibit high color purity red light emission, but their limited water resistance hinders practical applications. In this study, citric and oxalic acids are innovatively employed for surface modification, resulting in luminescent materials with enhanced water resistance while preserving their luminescent intensity. This enhancement provides a prerequisite for their application in anti-counterfeiting films and aqueous fluorescent inks. Furthermore, the potential for optical information storage is successfully demonstrated by utilizing the photochromic fluorescent properties of polyvinyl alcohol films deposited on oxalic acid-modified K 2 SiF 6 :Mn4+. Exploiting the 3 ms day time difference between equivalently and non-equivalently doped Mn4+ fluoride, a millisecond information encryption mode is proposed by combining oxalic acid-modified K 2 SiF 6 :Mn4+ (long decay time, τ = 8.99 ms) and K 3 AlF 6 :Mn4+ (short decay time, τ = 5.31 ms). This mode can be effectively decoded using digital cameras and editing software, achieving high-level anti-counterfeiting capabilities. This work advances the application of highly efficient Mn4+-activated red phosphors in the realm of information security. [ABSTRACT FROM AUTHOR]

Tooth enamel, and especially the outer tooth enamel, is a load-resistant shell that benefits mastication but is easily damaged, driving the need for enamel-restorative materials with comparable properties to restore the mastication function and protect the teeth. Synthesizing an enamel analog that mimics the components and hierarchical structure of natural tooth enamel is a promising way to achieve these comparable mechanical properties, but it is still challenging to realize. Herein, we fabricate a hierarchical enamel analog with comparable stiffness, hardness, and viscoelasticity as natural enamel by incorporating three hierarchies of outer tooth enamel based on hierarchical assembly of enamel-like hydroxyapatite hybrid nanowires with polyvinyl alcohol as a matrix. This enamel analog possesses enamel-similar inorganic components and a nanowire-microbundle-macroarray hierarchical structure. It exhibits toughness of 19.80 MPa m1/2, which is 3.4 times higher than natural tooth enamel, giving it long-term fatigue durability. This hierarchical design is promising for scalable production of enamel-restorative materials and for optimizing the mechanical performance of engineering composites. Mechanical compatibility is highly desirable for enamel restorative materials. Here, the authors engineer a hierarchical enamel analog with comparable mechanical properties as outer enamel, showing great potential for enamel restoration. [ABSTRACT FROM AUTHOR]

Daytime radiative cooling material provides a low‐energy way of cooling because it can reflect sunlight and radiate heat without consuming any energy. However, there are still great difficulties in manufacturing low‐cost, high‐efficiency, sustainable, and biodegradable daytime radiative cooling materials. In this paper, poly (vinyl alcohol)/boron nitride (PVA/BN) composite aerogels were prepared by freeze‐drying technology. By adjusting the PVA concentration and BN content, the aerogel can achieve high sunlight reflectivity (96%), high mid‐infrared emissivity (96%) and good thermal insulation performance. Therefore, the temperature of the aerogel can be reduced to 12.5°C lower than the ambient temperature at night, and 5.5°C lower than the ambient temperature under the direct sunlight of 900 W/m2. This aerogel opens an environmentally sustainable pathway for radiative cooling applications. [ABSTRACT FROM AUTHOR]