Polyvinyl Alcohol Concentration Research Articles

Design and optimization of acetazolamide nanoparticle-laden contact lens using statistical experimental design for controlled ocular drug delivery

This study aims to formulate and evaluate Eudragit nanoparticles-laden hydrogel contact lenses for controlled delivery of acetazolamide (ACZ) using experimental design. Eudragit S-100 was selected for the preparation of nanoparticles. The optimization of Eudragit S100 concentration (X1), polyvinyl alcohol concentration (X2), and the sonication time (X3) was attempted by applying a central composite experimental design. Mean size of nanoparticles (nm), percent in vitro drug release and drug leaching from the ACZ-ENs laden contact lens were considered as dependent variables. Nanoparticles-laden contact lens was prepared through the direct loading method and characterized. Optimum check-point formulation was selected based on validated quadratic polynomial equations developed using response surface methodology. The optimized formulation of ACZ-ENs exhibited spherical shape with a size of 244.3 nm and a zeta potential of −13.2 mV. The entrapment efficiency of nanoparticles was found to be 82.7 ± 1.21%. Transparent contact lenses loaded ACZ-ENs were successfully prepared using the free radical polymerization technique. ACZ-ENs incorporated in contact lens exhibited a swelling of 83.4 ± 0.82% and transmittance of 80.1 ± 1.23%. ACZ-ENs showed a significantly lower burst release of the drug when incorporated in the contact lens and release was sustained over a period of 24 h. The sterilized formulation of ACZ-ENs laden contact lens did not show any sign of toxicity in rabbit eyes. ACZ-ENs incorporated in contact lens could be considered as a potential alternative in glaucoma patients due to their ability to provide sustained drug release and thus enhance patient compliance.

Sustained release microneedle patch for pronounced systemic delivery of doxazosin mesylate

Introduction: Microneedle patch is one of the fascinating drug delivery approaches that offers low invasiveness and a painless physical application to enhance the delivery of micro and macro-molecules into the skin. Methods: Variable contents of chitosan and polyvinyl alcohol were used for the development of doxazosin mesylate containing sustained release microneedle patches via solvent casting technique. The prepared patches were evaluated for microscopic evaluation, mechanical strength, drug loading (%) and Fourier transform infrared spectroscopy (FTIR) etc. The skin penetration study was performed by using pig ear skin and results were captured through confocal microscopy. Ex-vivo release study and pharmacokinetic evaluation were also performed. Results: Sharp needle tips with a height of 600µm and a base of 200µm were confirmed through microscopic examination. Optimized formulation (SRF-6) exhibited loading of 92.11% doxazosin mesylate with appreciable strength up to 1.94N force. Ex-vivo release studies revealed 87.24% release within 48 hours. Moreover, the pharmacokinetic parameters in case of optimized patch formulation (SRF-6) were markedly improved i.e. MRT (19.46 h), AUC (57.12 μg.h /mL), Cmax (2.16 µg /mL), tmax (10.10 h) and t1/2 (6.32 h) as compared to commercially available tablet. Biocompatibility of the developed patches was validated from skin irritation studies. Conclusion: Results confirmed the successful fabrication of microneedle patch having sufficient strength and effective penetration ability into the skin to ensure controlled release of incorporated drug for the intended duration. It can be employed as an efficient carrier system for other therapeutics those are prone to bioavailability issues due to first pass effect after their oral administration.

Preparation and Characterization of Hydroxyapatite Based Composite Material via Cold Sintering Process

This study focuses on the synthesis of hydroxyapatite (HA) from bovine bones through calcination and subsequent combination with Polyvinyl Alcohol (PVA) using the Cold Sintering Process (CSP). The CSP, operating at lower temperatures than conventional methods, aims to preserve the bioactivity and biocompatibility of HA, crucial for biomedical applications. The research investigates the influence of HA composition, sintering temperature, and PVA content on the porosity and compressive strength of the HA-PVA composite. The Hydroxyapatite powder, obtained from calcinated bovine bones, exhibits irregular shapes and sizes with a maximum grain size of 10µm, confirmed by SEM analysis. XRD analysis validates the successful production of Hydroxyapatite, showcasing characteristic peaks. The HA/PVA composite's XRD pattern indicates the dominance of HA, with PVA present as well. The study produces 27 specimens through the CSP, varying HA composition and sintering temperature. Porosity increases with higher HA content and sintering temperature, attributed to the role of PVA in binding HA particles. Compressive strength rises with increased HA content, emphasizing HA's role in enhancing mechanical strength. The presence of porosity is mitigated by a strong bond between HA and PVA, contributing to structural integrity. This research provides insights into tailoring HA-PVA materials for biomedical applications, considering controlled porosity and mechanical strength. The CSP, with its unique advantages, emerges as a promising method for developing customized materials to meet diverse biomedical needs.

Enhancing the Biodegradability, Water Solubility, and Thermal Properties of Polyvinyl Alcohol through Natural Polymer Blending: An Approach toward Sustainable Polymer Applications.

The escalating environmental crisis posed by single-use plastics underscores the urgent need for sustainable alternatives. This study provides an approach to introduce biodegradable polymer blends by blending synthetic polyvinyl alcohol (PVA) with natural polymers-corn starch (CS) and hydroxypropyl methylcellulose (HPMC)-to address this challenge. Through a comprehensive analysis, including of the structure, mechanical strength, water solubility, biodegradability, and thermal properties, we investigated the enhanced performance of PVA-CS and PVA-HPMC blends over conventional polymers. Scanning electron microscopy (SEM) findings of pure PVA and its blends were studied, and we found a complete homogeneity between the PVA and both types of natural polymers in the case of a high concentration of PVA, whereas at lower concentration of PVA, some granules of CS and HMPC appear in the SEM. Blending corn starch (CS) with PVA significantly boosts its biodegradability in soil environments, since adding starch of 50 w/w duplicates the rate of PVA biodegradation. Incorporating hydroxypropyl methylcellulose (HPMC) with PVA not only improves water solubility but also enhances biodegradation rates, as the addition of HPMC increases the biodegradation of pure PVA from 10 to 100% and raises the water solubility from 80 to 100%, highlighting the significant acceleration of the biodegradation process and water solubility caused by HPMC addition, making these blends suitable for a wide range of applications, from packaging and agricultural films to biomedical engineering. The thermal properties of pure PVA and its blends with natural were studied using diffraction scanning calorimetry (DSC). It is found that the glass transition temperature (Tg) increases after adding natural polymers to PVA, referring to an improvement in the molecular weight and intermolecular interactions between blend molecules. Moreover, the amorphous structure of natural polymers makes the melting temperature ™ lessen after adding natural polymer, so the blends require lower temperature to remelt and be recycled again. For the mechanical properties, both types of natural polymer decrease the tensile strength and elongation at break, which overall weakens the mechanical properties of PVA. Our findings offer a promising pathway for the development of environmentally friendly polymers that do not compromise on performance, marking a significant step forward in polymer science's contribution to sustainability. This work presents detailed experimental and theoretical insights into novel polymerization methods and the utilization of biological strategies for advanced material design.

Charge-patterned nanofiltration membranes with polystyrene sulfonate particles and polyethyleneimine in cross-linked polyvinyl alcohol

Removing salinity has always been a challenge for wastewater treatment. Utilizing nanofiltration (NF) membranes is a promising approach. However, currently available NF membranes are less effective in monovalent salt removal. In this study, work toward the initial aim of fabricating charge mosaic membranes led to charge-patterned NF-selective films on polyether sulfone (PES) or polyacrylonitrile (PAN) support membranes, with similar rejection for mono- and divalent salts. The membranes were fabricated by a two-step layer assembly of first negatively charged polystyrene sulfonate (PSS) particles immobilized in a polyvinyl alcohol (PVA) layer, followed by coating a positively charged polyethyleneimine (PEI) layer. Both PVA and PEI were crosslinked using glutaraldehyde that had initially been impregnated into the support membrane. The type of support membrane, nanoparticle, PVA, and PEI concentrations during fabrication, as well as feed pH and salt concentration, play significant roles in separation performance of obtained composite membranes. Charge-patterned NF membranes fabricated using 0.5 wt.% PVA and 0.05 wt.% PSS for assembly of the first layer followed by coating 0.5 wt.% PEI solution had even somewhat higher rejection for monovalent salt (NaCl; ∼82%) compared to multivalent salts (Na2SO4, MgSO4, and MgCl2; ∼74%), at a permeance of 5.5 LMH/bar on the PES and 3.1 LMH/bar on the PAN support membrane.

Solar collector inspired by the polar bear: Fluorescent‐reinforcing photothermal conversion efficiency

AbstractThe crucial point of solar thermal utilization makes solar heat collector gathering much attention. In this study, imitating polar bears' fur structure, fluorescent materials are modified into a solar heat collector, and the photothermal conversion is evaluated to examine the influence of polyvinyl alcohol concentration, fluorescent luminescence type and fluorescence concentration. The test results indicate that fluorescent materials that has a greater Stokes shift show the greater photothermal effect. Moreover, when composed of a PVA concentration being 5.0% and a fluorescent concentration being 0.50%, the composites exhibit the maximal photothermal conversion temperature (99.4°C) that is 17.9% higher than that of the solar heat collectors without fluorescent materials. This study proposes creating solar heat collector with modified fluorescent materials, and the new perspective of which demonstrates that the composites have a great potential and application prospect in the solar photothermal field.

Revolutionizing green growth: unleashing the power of PVA and CaHPO4 in crafting a sustainable future through innovative PBS/PVA biodegradable composites for seedling cultivation

ABSTRACT This study introduces an innovative utilizing polybutylene succinate (PBS) and polyvinyl alcohol (PVA) for seedling bags, enriched with glycerol (G) and calcium hydrogen phosphate (CaHPO4) fertilizer. The investigation examined the impact of PVA (10–50 wt.%) with fixed glycerol ratio of 20 phr, and CaHPO4 content (0–7 phr) on the composite. Notably, higher PVA content led to better dispersion of PVA particles within the PBS/G blend, reducing phase separation compared to lower PVA content. However, increased PVA content resulted in decreased mechanical properties due to incompatibility and phase separation, as well as interference with PBS crystallization. Regarding CaHPO4, the addition of a low fertilizer amount (3 phr) slightly reduced crystallinity (from 40% to 19%) but increased elongation at break (from 2.7% to 3.8%). Conversely, higher CaHPO4 content (5–7 phr) significantly enhanced tensile strength and elongation at break to 5.6 MPa and 6.3%, respectively, without affecting crystallinity. Importantly, CaHPO4 incorporation improved the dispersion of PVA within the PBS matrix. In practical application, PBS/PVA/G/CaHPO4 composites proved suitable for planting seedlings, which thrived in the bags over 42 days. This study underscores the potential of these composite materials for seedling cultivation, while future research may delve into optimizing fertilizer effectiveness in this context.

Optimization of LiNiCoMnO2 Cathode Material Synthesis Using Polyvinyl Alcohol Solution Method for Improved Lithium-Ion Batteries.

The growing need for lithium-ion batteries, fueled by the widespread use of electric vehicles (EVs) and portable electronic devices, requires high energy density and safety. The cathode material Li1-x(NiyCozMn1-y-z)O2 (NCM) shows promise, but attaining high efficiency necessitates optimization of both composition and manufacturing methods. Polycrystalline LiNiCoMnO2 powders were synthesized and assessed in this investigation using a polyvinyl alcohol (PVA) solution method. The study examined different synthesis conditions, such as the PVA to metal ions ratio and the molecular weight of PVA, to assess their influence on powder characteristics. Electrochemical analysis indicated that cathode materials synthesized with a relatively high quantity of PVA with a molecular weight of 98,000 exhibited the highest discharge capacity of 170.34 mAh/g and a high lithium-ion diffusion coefficient of 1.19 × 10-9 cm2/s. Moreover, decreasing the PVA content, irrespective of its molecular weight, led to the production of powders with reduced surface areas and increased pore sizes. The adjustments of PVA during synthesis resulted in pre-sintering observed during the synthesis process, which had an impact on the long-term stability of batteries. The electrodes produced from the synthesized powders had a positive impact on the insertion and extraction of Li+ ions, thereby improving the electrochemical performance of the batteries. This study reveals that cathode materials synthesized with a high quantity of PVA with a molecular weight of 98,000 exhibited the highest discharge capacity of 170.34 mAh/g and a high lithium-ion diffusion coefficient of 1.19 × 10-9 cm2/s. The findings underscore the significance of optimizing methods for synthesizing PVA-based materials to enhance the electrochemical properties of NCM cathode materials, contributing to the advancement of lithium-ion battery technology. The findings underscore the significance of optimizing methods for synthesizing PVA-based materials and their influence on the electrochemical properties of NCM cathode materials. This contributes to the continuous progress in lithium-ion battery technology.

Preparation of starch/PVA nanoparticles and evaluation of their ability to stabilize Pickering emulsions

Biodegradable and biocompatible polymer-based nanoparticles (NPs) hold great promise for various industries. We report the first development of composite NPs consisting of starch (St) and polyvinyl alcohol (PVA) using the nanoprecipitation technique with ethanol as an antisolvent. We varied the St:PVA ratios in the precursor solutions to evaluate their impact on the structure and properties of the composite NPs. The ratios used were 4:1, 1:1, and 1:4. Characterization by X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis revealed distinct XRD and TGA patterns for the composite St/PVANPs compared to their corresponding physical blends. This indicated the presence of mixed St/PVA crystallites within their structures. Additionally, the crystallinity of St/PVANPs increased with rising St content. Dynamic light scattering and scanning electron microscopy showed that nanoparticle sizes increased with higher PVA proportions. The St/PVANPs showed superior performance as stabilizers in Pickering emulsions, forming denser continuous networks in the gel-like structure of the emulsions. Additionally, increasing the PVA content in the composition of St/PVANPs strengthened the structure of Pickering emulsions. The emulsion stabilized by St20/PVA80NPs showed exceptional stability for one month. These findings highlight the potential of St/PVANPs as innovative materials for various applications, including emulsion stabilization.

Processing physically crosslinked polyvinyl alcohol hydrogel into solid foams via freeze-drying: The role of hydrogel state

Processing hydrogels into solid foams or aerogels via freeze-drying broaden their applications. However, one challenge is its inherent processing instability, often leading to dimensional shrinkage and structural collapse of the resultant solid foams. To address this, our study investigated the role of hydrogel state in the solid foam formation. Specifically, polyvinyl alcohol (PVA) hydrogel, synthesized through repeated freeze-thaw (FT) cycles, was investigated. It was found that PVA concentration and FT cycles played a vital role; specifically, higher PVA concentration and more FT cycles negatively affected solid foam formation. These hydrogels exhibited an increase in hydrogel viscoelasticity and crystallizability of the most flexible chains, indicative of strong and denser network structure. We proposed that the final solid foam structure was determined by a balance between the volumetric expansion due to water-to-ice transition during freezing and the intense inter-polymeric chain attractions within the denser network during sublimation.

Bubble linking anterior growth strategy to prepare hydrogel tubes with different range, branch and voyager function

Hydrogel tubes (HTs) represent a significant facet of hydrogel morphology. Nevertheless, the continuous, rapid, and facile fabrication of hydrogel tubes remains a formidable challenge. In this study, we introduce a novel technique named as Anterior Growth (AG) for the continuous preparation of HTs. This innovative approach employs air bubbles as guidance to direct the growth of polyvinyl alcohol (PVA) HTs crosslinked by copper ions in alkaline solution. Various factors that affect the sizes of HTs from micrometers to millimeters have been explored, including gauge of needles, air bubble volumes, injection rates, and concentrations of NaOH, copper nitrate and PVA. Single HT with various sizes can be easily fabricated by simply adjusting injection rates. The reversibility of PVA-Cu2+ crosslinking makes it possible to produce HTs with multiple branches in a convenient way by generating an orifice out of the HT wall and then repeating the growing process. Inspired by plant thigmotropism, HTs can be guided to grow along designed shapes such as different angles and patterns by combination of air bubble and silicone rubble substrates. Remarkably, this method allows HTs to serve as voyagers navigating intricate flow channels with a projected trajectory, indicating the capabilities of patterning and traversing complex channels. To further application, AG allows other materials to prepare HTs such as sodium alginate or more, showcasing excellent practical value.

Development of inorganic anticorrosive coatings for steel bars: Corrosion resistance testing and design

A densely structured three-dimensional geopolymer network could effectively impede the migration and diffusion of chloride ion. This study developed one kind of efficient and cost-effective and multi-component geopolymer coating (MGC) for inhibiting and delaying the corrosion of steel. The influence of alkali content, metakaolin replacement ratio, polyvinyl alcohol content, and titanium dioxide content on the fluidity, setting time, and rheological properties of MGC was investigated. Accelerated corrosion tests were carried out to determine the optimal formulation of MGC. The corrosion resistance of MGC prepared by different coating method was compared to commercial organic metal coatings, for which the salt spray test, adhesion test, and electrochemical impedance spectroscopy test were conducted. The results showed that the dip-coated specimen of MGC exhibited 63.8% decrease in mass loss, 59.5% decrease in adhesive strength loss, and 38.1% increase in impedance modulus compared to commercial organic metal coatings. Furthermore, the corrosion protection mechanism of MGC was elucidated by analyzing its microstructural characteristics including the functional groups formed on the surface of coated steel bars. In terms of cost, MGC reduced the total cost by about 15 times compared to commercial organic metal coatings.

Formulation and Characterization of Triamcinolone Acetonide Acetate-Loaded Microspheres Prepared by a Static Mixing Technique

Purpose: Reproducibility and scale-up production of microspheres through spray drying present significant challenges. In this study, biodegradable microspheres of Triamcinolone Acetonide Acetate (TAA) were prepared using a novel static mixing method by employing poly( lactic-co-glycolic acid) (PLGA) as the sustained-release carrier. Methods: TAA-loaded microspheres (TAA-MSs) were prepared using a static mixing technique. The PLGA concentration, polyvinyl alcohol concentration (PVA), phase ratio of oil/water, and phase ratio of water/solidification were optimized in terms of the particle size, drug loading (DL), and encapsulation efficiency (EE) of TAA-MSs. The morphology of TAA-MSs was examined using Scanning Electron Microscopy (SEM), while the physicochemical properties were evaluated through X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC), and Fourier Transform Infrared Spectroscopy (FT-IR). The in vitro release of TAA-MSs was compared to that of the pure drug (TAA) using a water-bath vibration method in the medium of pH 7.4 at 37°C. Results: The formulation composition and preparation condition for the preparation of TAA-MSs were optimized as follows: the PLGA concentration was 1%, the phase ratio of oil(dichloromethane) /water (PVA solution) was 1:3, the phase ratio of water (PVA solution)/solidification was 1:2. The optimized TAA-MSs displayed spherical particles with a size range of 30-70 μm, and DL and EE values of 27.09% and 98.67%, respectively. Moreover, the drug-loaded microspheres exhibited a significant, sustained release, with 20% of the drug released over a period of 28 days. The XRD result indicated that the crystalline form of TAA in microspheres had been partly converted into the amorphous form. DSC and FT-IR results revealed that some interactions between TAA and PLGA occurred, indicating that the drug was effectively encapsulated into PLGA microspheres. Conclusion: TAA-loaded PLGA microspheres have been successfully prepared via the static mixing technique with enhanced EE and sustained-release manner.

Biodegradable Foam from Cassava Starch Blended with Water Hyacinth Fiber: Effects of Polyvinyl Alcohol Content

Abstract Our previous investigation revealed that the addition of water hyacinth fiber (WHF) and polyvinyl alcohol (PVA) enhanced the mechanical properties of cassava starch-based foam. However, the effect of PVA concentration on the mechanical properties of starch foam is still unclear. Therefore, this study examined the effects of various concentrations of PVA on the foam’s quality and production process. Four levels of PVA (0, 1, 2, and 3% w/w) were tested on the mixed dough of cassava starch and 15% of WHF. The foam was made by baking the dough on a thermopressing machine at a temperature of 190 °C for 3 min. The quality level of foams was determined by their physical and mechanical (compressibility, water adsorption, density, color appearance, and biodegradability) properties as well as the practicality of the dough preparation and baking processes. As a result, the addition of PVA significantly affects the mechanical properties and ease of making dough. A higher concentration of PVA contributed to a better mixture of the dough, resulting in a smoother mixing process that led to foams with stronger mechanical properties. Nevertheless, the application of 2% and 3% PVA did not make a significant difference in the mechanical and physical properties. Foam with 2% PVA showed 32 N/mm2 of compressibility, 10% water absorptivity, 12% water content, and good biodegradability, with 87% of the material lost during 30 days of burial in the soil.

Stability and release mechanism of double emulsification (W1/O/W2) for biodegradable pH-responsive polyhydroxybutyrate/cellulose acetate phthalate microbeads loaded with the water-soluble bioactive compound niacinamide

Microbeads of biodegradable polyhydroxybutyrate (PHB) offer environmental benefits and economic competitiveness. The aim of this study was to encapsulate a water-soluble bioactive compound, niacinamide (NIA), in a pH-responsive natural matrix composed of PHB and cellulose acetate phthalate (CAP) by double emulsification (W1/O/W2) to improve the encapsulation efficiency (%EE) and loading capacity (%LC). PHB was produced in-house by Escherichia coli JM109 pUC19-23119phaCABA-04 without the inducing agent isopropyl β-D-1-thiogalactopyranoside (IPTG). The influences of PHB and polyvinyl alcohol (PVA) concentrations, stirring rate, PHB/CAP ratio and initial NIA concentration on the properties of NIA-loaded pH-responsive microbeads were studied. The NIA-loaded pH-responsive PHB/CAP microbeads exhibited a spherical core-shell structure. The average size of the NIA-loaded pH-responsive microbeads was 1243.3 ± 11.5 μm. The EE and LC were 33.3 ± 0.5 % and 28.5 ± 0.4 %, respectively. The release profiles of NIA showed pH-responsive properties, as 94.2 ± 3.5 % of NIA was released at pH 5.5, whereas 99.3 ± 2.4 % of NIA was released at pH 7.0. The NIA-loaded pH-responsive PHB/CAP microbeads were stable for >90 days at 4 °C under darkness, with NIA remaining at 73.65 ± 1.86 %. A cytotoxicity assay in PSVK1 cells confirmed that the NIA-loaded pH-responsive PHB/CAP microbeads were nontoxic at concentrations lower than 31.3 μg/mL, in accordance with ISO 10993-5.

Durability and Mechanical Properties of Nano-SiO2 and Polyvinyl Alcohol Fiber-Reinforced Cementitious Composites Subjected to Saline Freeze-Thaw Cycles.

To investigate the effects of nano-SiO2 (NS) and polyvinyl alcohol (PVA) fibers on the durability and mechanical properties of cementitious composites subjected to saline freeze-thaw cycling, a series of PVA fiber-reinforced cementitious composite (PFRCC) specimens were prepared using various fiber contents, and a series of NS and PVA fiber-reinforced cementitious composite (NPFRCC) specimens were prepared using various combinations of NS and fiber contents. Durability and fracture toughness tests were subsequently conducted on the specimens after different numbers of saline freeze-thaw cycles. The results indicate that the degradation of material properties can be divided into slow and accelerated damage stages before/after 50 freeze-thaw cycles. The durability and fracture toughness of the specimen series tended to increase, then decrease with increasing NS and PVA contents, suggesting optimum levels. When the PVA fiber content was 0.5%, PFRCC specimens had the best durability after saline freeze-thaw cycles; when the NS and PVA fiber contents were 1.0% and 0.5%, respectively, NPFRCC specimens had the best durability and fracture properties, and the initiation toughness, destabilization toughness, and fracture energy after 100 saline freeze-thaw cycles were 120.69%, 160.02%, and 451.31%, respectively. The results of this study may guide future exploration of the durability and mechanical properties of concrete subjected to freeze-thaw action.

Robust construction of polyvinyl alcohol intercalated graphene oxide nanofiltration membrane for desalination via pervaporation

The construction and modification of a Graphene Oxide (GO) membrane, incorporating polyvinyl alcohol (PVA) cross-linked with maleic acid (MA) and supported by a nylon membrane, have been successfully completed. Systematic variations in PVA and MA concentrations were conducted to achieve membranes with favorable characteristics, stability, and excellent desalination performance. Optimization studies utilizing the Central Composite Design (CCD) revealed that the most optimal desalination results were obtained with 10 mL of PVA (0.1 mg mL−1) and 0.9 M of MA (GO-MA0.9-PVA10/Nylon membrane). Experimental findings demonstrated that the inclusion of PVA and MA resulted in an increased interlayer distance of GO and enhanced membrane stability. The addition of PVA increases GO membrane hydrophilicity, while the addition of MA reduces membrane hydrophilicity. The GO-MA0.9-PVA10/Nylon membrane exhibited the highest desalination performance, boasting a rejection value exceeding >99.9% and a permeance of 18.76 kg m−2.h−1 under 1% NaCl feed at a temperature of 50 °C. This membrane demonstrated consistent desalination performance stability over an extended period of up to 70 h. Moreover, it exhibited durability through 8 cycles of 24-h usage with washing treatment. In conclusion, the GO-MA0.9-PVA10/Nylon membrane is strongly recommended for practical applications, outperforming other membrane options based on the comprehensive evaluation of its stability and desalination efficiency.

Ionic thermoelectricity of salt-free PVA-hydrogel

As polyvinyl alcohol (PVA) hydrogels have shown a high potential as an ionic thermoelectric generator, this paper aims to study the thermoelectric (TE) power of salt-free PVA hydrogel. Ionic thermoelectric performance, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) are measured at different relative humidities. Findings show that salt-free PVA hydrogels can achieve a relatively high Seebeck (9.26 mV K−1) using only surrounding moisture. Hydrogels with low PVA content have a more stable TE output than hydrogels with high PVA content in high relative humidity conditions. Embedded Ni-foam-CNT electrodes stabilize performance, reduce noise, and provide superior capacitance, resistance, and thermoelectric performance over direct drop-casting of CNT on hydrogels. Recommended operating relative humidity (RH) ranges between 40 % and 60 %, while recommended PVA content ranges from 10 % to 15 % mass ratio of PVA in water. The results pave the way for using PVA hydrogels as thermoelectric devices in biocompatible applications.

The Effect of Polyvinyl Alcohol Addition on the Optical Properties and Oxygen Detection Performance of Titanium Dioxide and Methylene Blue Nanocomposite Colorimetric Indicators.

In this study, we investigated the impact of polyvinyl alcohol (PVA) incorporation on the optical properties and oxygen detection performance of a titanium dioxide/methylene blue (TiO2/MB) nanocomposite colorimetric indicator for packaging applications. The nanocomposite was synthesized via mechanical milling of TiO2 nanoparticles with MB and citric acid. PVA, at varying concentrations (0, 3, 9, and 14 wt%), was introduced during the wet milling process to produce a homogeneous composite film. Spin coating was employed to fabricate TiO2/MB nanocomposite films for oxygen detection evaluation. The influence of PVA loading on the films' chemical functionalities and surface morphologies was assessed using Fourier-transform infrared spectroscopy (FTIR) and field-emission scanning electron microscopy (FE-SEM). The indicator's activation process, involving a color change between bleached and colored states, and its recovery time were monitored via optical imaging and UV-VIS-NIR spectrophotometry. The results revealed that a PVA content of 9 wt% yielded well-defined films with enhanced stability of the TiO2/MB nanocomposite's oxygen detection performance.

Characterization of polyvinyl alcohol and vitex negundo blended bio nanofilm for wound healing scaffold

Polyvinyl alcohol blended nanofilms have shown great promise as a material for wound healing applications because of their biocompatibility, biodegradability, and antibacterial characteristics. This article has typically utilized electrospinning to create a scaffold for wound healing meanwhile investigating the characteristics of the polyvinyl alcohol (PVA) and vitex negundo (VN) blend nanofilm. The PVA concentrations were kept at 10% Weight/Volume (W/V), which was then mixed with VN solution at various volumetric ratios and electrospun into nanofilms. Field Emission Scanning Electron Microscopy (FESEM) was used to determine and analyze the nanofiber diameter. The plant extract concentration and the viscosity of the electrospinning solution influenced the fiber diameter to grow from 120.32 nanometers (nm) to 171.11 nanometers (nm). Fourier Transform Infrared Spectroscopy (FTIR) verifies the interaction between plant extract and PVA and records a new peak between 1731 and 1750 cm−1, which represents the production of the ester group. The swellability of the developed sample was studied which is negligibly reduced when the plant extract was added. In comparison to both Gram-positive and Gram-negative bacteria, the pure plant extract and composite nanofibrous web demonstrated greater antibacterial activity. PVA-blended nanofilms can promote cell migration, proliferation, and differentiation, hence promoting wound healing by creating a moist environment.