Polyvinyl Alcohol Research Articles

Ease-of-manufacture highly transparent thin polyvinyl alcohol aerogel

The earliest silicon-based aerogels attracted attention due to their nanoscale porous structure and high transparency. Still, they need to be more balanced with the poor mechanical properties. Their brittle structure limits the development of this promising new material. Therefore, the goal of this work is to optimize the mechanical properties of aerogels while maintaining transparency. The good mechanical properties of polymers have made them the material of choice for this work. Polyvinyl alcohol (PVA), which can undergo self-crosslinking through side-chain hydroxyl groups forming hydrogen bonds, was chosen as the raw material to simplify and expedite the production process. The production process was experimented with, analyzed, and refined. Considering the time efficiency of the experimental process, a one-step gelling method was invented to facilitate the sol-gel transition. The one-step gelling method maintained the high transparency of PVA aerogels and reduced the time required for the gelation process compared to the freeze-thawing method. This work employs carbon dioxide supercritical drying to ensure minimal structural collapse and maximize the porous structure’s retention. The transmittance of PVA aerogels can reach up to 93.67% at a wavelength of 1333 nm. The internal structure of aerogels with different PVA concentrations was observed using a Scanning electron microscope. Applying Beer-Lambert’s Law eliminated the effect of sample thickness on transparency. The relationship between the transparency of PVA aerogels, their microstructure, and macroscopic concentration was studied and analyzed for the first time. While ensuring light transmittance, the modulus of the PVA aerogel reached as high as 6.18 ± 0.56 MPa at 13 wt%.

Fluorescence Enhancement of Nonemissive Monodeprotonated Luteolin in a Poly(vinyl alcohol) Film.

Solid polymer matrixes can modulate the electronic states of embedded chromophores and have been widely used in flexible optoelectronic and optical materials. Luteolin is one of the most common natural flavonoids, and its neutral and monodeprotonated forms are nonemissive in aqueous solution induced by ultrafast excited-state proton transfer (ESPT) followed by nonradiative relaxation. In this study, we have incorporated luteolin into poly(vinyl alcohol) (PVA) films and studied their fluorescence behaviors. Neutral and one monodeprotonated luteolin coexist in the PVA film. Weak steady-state fluorescence of neutral luteolin peaking at about 440 nm is observed for the first time. In addition, the monodeprotonated luteolin in PVA film exhibits obvious fluorescence peaking at 500 nm, with a fluorescence quantum yield of as high as 0.4 and a fluorescence lifetime of as long as 2.4 ns. Time-dependent density functional theory calculations have determined that the ESPT of neutral luteolin is barrierless but that of monodeprotonated luteolin needs to surmount a barrier, explaining their distinct emission properties. These results indicate the modulation ability of the PVA film in both ground-state deprotonation and ESPT, broadening the application areas of the solid polymer matrix.

Construction and characterization of sodium alginate/polyvinyl alcohol double-network hydrogel beads with surfactant-tailored adsorption capabilities for efficient tetracycline hydrochloride removal

The extensive use of tetracycline (TC) for disease control and the residuals in wastewater has resulted in the spread and accumulation of antibiotic resistance genes, posing a severe threat to the human health and environmental safety. To solve this problem, a series of double-network hydrogel beads based on sodium alginate and polyvinyl alcohol were constructed with the introduction of various surfactants to modulate the morphology. The results showed that the introduction of surfactants can modulate the surface morphology and internal structure, which can also regulate the adsorption ability of the hydrogel beads. The SDS-B beads with SDS as surfactant exhibited highest adsorption efficiency for removal of TC with a maximum adsorption capacity up to 121.6 mg/g, which possessed a resistance to various cations and humic acid. The adsorption mechanism revealed that the superior adsorption performance of the hydrogel beads was primarily attributed to hydrogen bonding, electrostatic attraction, and π-π EDA interactions. Adsorption kinetics demonstrated that the pseudo-second-order model fitted the adsorption process well and adsorption isotherm showed the adsorption of TC occurred through both chemical and physical interactions. Moreover, the adsorption efficiency remained approximately 87.5 % after three adsorption-desorption cycles, which may have potential application and practical value in TC adsorption.

Enhanced photocatalytic performance of (Mg, Cu) Dual-Doped ZnS nanosheets for Solar-Driven water treatment and embedded with PVA polymer membrane for reusability

Photocatalysis uses semiconductor materials to solar energy effectively purify to water by eliminating pollutants. Organic Dye degradation serves as a standard to assess the photocatalytic effects of the materials. In this study Mg, Cu dual-doped ZnS nanosheets were synthesized using the coprecipitation method. The impact of the concentration on the structural, morphology, optical, and degradation efficiency was investigated with XRD, XPS, TEM with EDAX, and UV spectroscopy. The pure ZnS and Zn0.98-xCu0.02MgxS (x = 0, 0.01, 0.02) (ZCM1, ZCM2, ZCM3, and ZCM4) nanosheets, exhibited cubic structure with high phase purity. The average crystalline size was calculated as 1.66, 1.60, 1.45, and 1.47 nm for the ZCM1, ZCM2, ZCM3, and ZCM4 nanosheets, respectively. TEM analysis revealed the presence of crumpled nanosheets. The bandgap of the ZCM1, ZCM2, ZCM3, and ZCM4 nanosheets were 3.99, 3.78, 4.03, and 4.09 eV respectively. This study investigated the photocatalytic activity of crystal violet dye when exposed to natural sunlight irradiation. Notably, ZCM3 nanosheets exhibited a high degradation rate of 99 % over 120 min under sunlight. Furthermore, the proposed dye degradation mechanism, effect of dosage, effect of dye variation, reusability, scavenging activity, and hemolytic activity were comprehensively discussed. The nanosheets embedded with the Polyvinyl alcohol (PVA) polymer membrane for reusability.

A ratiometric indicator pad utilizing Alz/BRI-PVA for visual assessment of fish freshness

In this study, a novel intelligent water-absorbent cellulose pad with a specified area was developed for the visual and non-destructive monitoring of fish freshness. The pad’s substrate was composed of wood pulp cellulose (WPC), and the specified area contained a ratiometric mixture of brilliant blue (BRI) and alizarin (Alz)., fixed with Polyvinyl alcohol (PVA). During the freshness monitoring process, the Alz/BRI-PVA WPC pad exhibited a color transition from green to brown, followed by a shift to purple-red, corresponding to the increasing levels of total volatile base nitrogen (TVB-N) and total viable count (TVC). After testing, a BRI/Alz ratio of 1:8 was selected as the optimal ratio. Compared to the volatile gas-based sensing tags, the pad developed in this study demonstrated a high sensitivity of 53.4% by interacting with the sample exudate to produce signal changes. This study demonstrates the feasibility of using the developed dual-functional pad for water absorption and freshness indications.

Biocompatible Pickering emulsions and films: Unlocking the chitosan-polyvinyl alcohol synergy for multifaceted capabilities

The exciting potential of harnessing the synergy between polysaccharides and bioactive components is attracting significant scientific interest. This research paves the way for the development of novel materials that can improve human health. Therefore, current research is conducted to explore the innovative use of chitosan, polyvinyl alcohol (PVA) complex (CHN-PVA), olive oil-stabilized Pickering emulsions (PEs), and films with multifaceted applications. The sonication stabilized Pickering emulsions (PEs at different pH values 3, 5, 7, 9, and 11) exhibited decrease in particle size compared to control PEs. The pH significantly impacted the zeta potential of PEs. Fourier-transform infrared spectroscopy (FTIR) confirmed the non-covalent linkages. The antibacterial activity of the PEs revealed greater efficacy against gram-positive bacteria than gram-negative bacteria. The CHN-PVA synergy greatly impacted the mechanical properties of films, resulting in tremendous increase of tensile strength and elongation at break compared to CHN film. The PEs efficiently delivered quercetin at neutral pH. The electro spraying of PEs significantly extended strawberry shelf life. Finally, the films exhibited promising properties of adsorbent and the results depicted that pH had a significant impact on methylene blue removal. Conclusively, this investigation underscores the potential of CHN-PVA films in food, health, and environmental fields.

Structural, optical, and shielding investigation of PVA/Te composite for technological applications

Using the casting process, polymeric films made of polyvinyl alcohol (PVA) including varying percentages of Te were created to form PVA/Te composite at doping concentrations of Te (0, 4.76, 13.04, 20 wt %), which denoted as PT1, PT2, PT3 and PT4 respectively. XRD results show semicrystalline nature in PT1 and PT2 however with further increasing of Te contents, a nano-crystallite Te appeared in PT3 and PT4. The absorption spectrum confirms that PT3 film is a good option to be used in UV-shielding. PT4 film shows an abrupt rise in absorption coefficient at 0.5 eV, 1.5 eV and UV regions, hence this qualifies this sample for various optical applications. The optical energy gap of the films varies between 4.94 eV and 3.32 eV for the indirect transitions and between 5.3 eV and 4.5 eV for the direct transitions, the PT4 film has the lowest values of both direct and indirect energy gaps. Several methods were used to measure the average refractive index nav value. Furthermore, the nonlinear refractive index (n2) was estimated. PT4 possesses the highest value of both nav and n2. Furthermore, the radiation shielding coefficients have been estimated according to the Phy-X/PSD online software. The sample with the highest Te concentration, PT4, has the best radiation shielding between the films under investigation. The investigated polymer with high Te weight percentage is an optical system that can be used for solar cells, optoelectronics, electronics, nonlinear optics, optical filters and for radiation shielding.

A dynamic word conversion indicator based on water resistance poly (vinyl alcohol)/basic lead acetate nanofibers for monitoring shrimp freshness

A dynamic word conversion indicator based on water resistance poly (vinyl alcohol)/basic lead acetate nanofibers for monitoring shrimp freshness

Electrospun Sulfonated Poly(ether ether ketone) and Chitosan/Poly(vinyl alcohol) Bifunctional Nanofibers to Accelerate Proton Conduction at Subzero Temperature.

Multilayered microstructures can accelerate the proton conduction process in proton exchange membranes (PEMs). Herein, we design and construct PEMs with microstructures based on bifunctional nanofibers and sulfonated poly(ether ether ketone) (SPEEK) nanofibers. Specifically, the bifunctional nanofibers composed of poly(vinyl alcohol) and chitosan are prepared and then combined with the electrospun SPEEK nanofibers. The stable microstructure is derived from the compatible interfacial property of nanofibers and the formed hydrogen bonds. The multilayered microstructure consisting of nanofibers accelerates the proton conduction even at subzero temperature because of regulating the proton conduction pathways. Specifically, the (SKNF/CPNF/SKNF)/PA membrane exhibits the proton conductivities of (0.951 ± 0.138) × 10-2 S/cm at -30 °C and (7.32 ± 0.37) × 10-2 S/cm at 160 °C. Additionally, the fine proton conductivity stability is demonstrated by the proton conductivity in the long-term test and the cooling/heating cycle test, such as 1.67 × 10-2 S/cm at -30 °C (after 1000 h), 4.52 × 10-2 S/cm at 30 °C (after 810 h), 1.12 × 10-2 S/cm at -30 °C, and 1.01 × 10-1 S/cm at 30 °C in the cooling/heating process (5 cycles). The single fuel cell possesses an open-circuit voltage of 0.886 V and a peak power density of 0.508 W/cm2 at 130 °C.

Functional composite films incorporating triphala-derived carbon dots for extending chicken preservation

Triphala-based carbon dots (T-CDs) were successfully prepared using a simple one-step hydrothermal method. T-CDs were characterized by absorbance, fluorescence, Fourier-transform infrared, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. T-CDs showed bright blue fluorescence at 434 nm upon excitation at 360 nm. Functional composite films were prepared using poly(vinyl alcohol) and gelatin mixture by incorporating T-CDs and applied as a packaging film to extend the shelf life of chicken. The antibacterial activity of T-CDs against Listeria monocytogenes and Staphylococcus aureus was evaluated using well diffusion and colony count methods. T-CDs were evenly dispersed throughout the PVA/Gel solution to form a dense and uninterrupted film. They also formed strong bonds with polymer chains, which improved the tensile strength of the film from 32.44 to 42.70 MPa. Furthermore, the presence of T-CDs significantly enhanced the UV-blocking ability of the PVA/Gel films, achieving 99.7 % for UV-B and 97.2 % for UV-A. In addition, the PVA/Gel/T-CDs composite films showed excellent antioxidant, antimicrobial and UV-barrier properties, extending the shelf life of chicken. Therefore, the PVA/Gel/T-CDs composite films showed great potential as an active food packaging material to extend the shelf life and preserve the visual quality of packaged meat.

Efficacy of a saline wash plus vancomycin/tobramycin-doped PVA composite (PVA-VAN/TOB-P) in a mouse pouch infection model implanted with 3D-printed porous titanium cylinders.

The efficacy of saline irrigation for treatment of implant-associated infections is limited in the presence of porous metallic implants. This study evaluated the therapeutic efficacy of antibiotic doped bioceramic (vancomycin/tobramycin-doped polyvinyl alcohol composite (PVA-VAN/TOB-P)) after saline wash in a mouse infection model implanted with titanium cylinders. Air pouches created in female BalBc mice by subcutaneous injection of air. In the first of two independent studies, pouches were implanted with titanium cylinders (400, 700, and 100 µm pore sizes) and inoculated with Staphylococcus aureus (1 × 103 or 1 × 106 colony-forming units (CFU)/pouch) to establish infection and biofilm formation. Mice were killed after one week for microbiological analysis. In the second study, pouches were implanted with 400 µm titanium cylinders and inoculated with S. aureus (1 × 103 or 1 × 106 CFU/pouch). Four groups were tested: 1) no bacteria; 2) bacteria without saline wash; 3) saline wash only; and 4) saline wash plus PVA-VAN/TOB-P. After seven days, the pouches were opened and washed with saline alone, or had an additional injection of PVA-VAN/TOB-P. Mice were killed 14 days after pouch wash. The first part of the study showed that low-grade infection was more significant in 400 µm cylinders than cylinders with larger pore sizes (p < 0.05). The second part of the study showed that saline wash alone was ineffective in eradicating both low- and high-grade infections. Saline plus PVA-VAN/TOB-P eradicated the titanium cylinder-associated infections, as manifested by negative cultures of the washouts and supported by scanning electron microscopy and histology. Porous titanium cylinders were vulnerable to bacterial infection and biofilm formation that could not be treated by saline irrigation alone. Application of PVA-VAN/TOB-P directly into the surgical site alone or after saline wash represents a feasible approach for prevention and/or treatment of porous implant-related infections.

Photothermal modulated hotspot for accurate and sensitive SERS detection of pesticides in complicated media

Designing smart surface-enhanced Raman scattering (SERS) nanosensors with superior sensibility, stabilities and repeatability is a challenging and intriguing goal in chemical measurement. Herein, we develop a photothermal modulated SERS platform (PM-SERS) for sensitive and stable analysis of targets by exploiting a stimuli-responsive gold nanoparticles (GNPs) decorated polyvinyl alcohol hydrogel (GPH). Importantly, the proposed GPH facilitates exactly controlling 3D hot-spot regions by modulating surrounding temperature and humidity. The adjustable GPH could not only act as a stable matrix for installing of high-density GNPs, but also as a sorption domain for preconcentration of targeted analyte in hot-spots sites, thus permitting simultaneously modulating 3D nanostructures and seizing targeted analytes in plasmonic regions. Crucially, because of the reversible nanostructures and nanoplasmonic features, GPH can eradicate adsorbates after being exposed to bromide solutions, thereby allowing renewable and reliable on-site SERS detection of complex media. The GPH-based PM-SERS platform exhibits excellent sensitivities and reproducibility for on-demand detection of multiplexed pesticide over a wide linear concentration range (2 × 10-6 to 103 μM), with detection limits as low as hundreds of fM. The GPH-based analytical platform provides tremendous potentials for credible quantification of complicated matrices and on-line process screening.

Surface patterned polyvinyl alcohol/CNT hydrogels for sustained solar powered high concentration brine desalination and salt harvesting

Solar-driven interfacial evaporation is an attractive way to achieve water purification. However, high water evaporation rates often result in the precipitation of salt crystals on the surface of the evaporator leading to decay of the evaporation efficiency over time, which makes it difficult to balance high water evaporation rates with salt resistance. Herein, an anisotropic polyvinyl alcohol/CNT hydrogel is constructed by directional freezing and surface patterning. The polymer backbone formed by the polyvinyl alcohol chains interacts with the water clusters to reduce the evaporation enthalpy of water and the absorbed water can be released by squeezing the hydrogels due to the micron-sized vertically aligned pores. More importantly, by designing the structure of the hydrogels surface, the gas–liquid interface of the evaporators can be increased while the growth direction of the salt crystals can be controlled. As a result, the water evaporation rate can be increased from 3.26 kg m-2h−1 to 3.69 kg m-2h−1 under one sun irradiation through surface patterning. After 50 h of continuous operation in 10 wt% NaCl solution under one sun irradiation, the water evaporation rate gradually increases and a large amount of salt collection is collected, which proves its satisfactory salt resistance.

Application of Box-Behnken design in the optimization and development of albendazole-loaded zein nanoparticles as a drug repurposing approach for colorectal cancer management

Colorectal cancer (CRC) is the second cancer worldwide representing a major global health challenge. Numerous effective anticancer drugs have been developed in the last decade, yet the problem remains due to their low therapeutic index and nonspecificity. A new anticancer therapeutic paradigm is based on repurposing and nanoformulating drugs. Albendazole (ALB), a popular anthelmintic agent, was recently repurposed against CRC cells. In this study zein, an amphiphilic protein, was used to formulate nanoparticles (NPs) loaded with ALB. Box-Behnken design was selected to optimize the loaded NPs, the concentrations of polyvinyl alcohol, acetic acid, and the weight of zein were the independent variables. The dependent variables were the particle size, polydispersity index, and zeta potential. The optimized formula displayed a size of 84.3 ± 0.41 nm, PDI 0.13 ± 0.012, and a zeta potential of 42.5 ± 2.35 mV. ALB was successfully encapsulated into zein NPs and the release study revealed a desirable pH-responsive drug release behavior, that was negligible discharge during the first 2 h at pH 1.2 and progressive in the simulated colon environment reaching 71.1 ± 0.34 % at 6 h and 92.4 ± 1.11 % at 24 h. The anticancer effect of the loaded NPs on the human HCT116 cells showed favorable effects at 1 μM concentrations with a significant decrease in the IC50 at days 2 and 3 upon loading albendazole into zein NPs. ZNPs proved to be prospective nanocarriers that could be used for the delivery of repurposed drugs in CRC treatment.

A Fluorescent Polyvinyl Alcohol Film with Efficient Photodynamic Antimicrobial Performance Enabled by Berberine/Phytic Acid Salt for Food Preservation

AbstractFood packaging that impedes microbial growth and can be safely used is critical to attenuate food spoilage. Herein, a green berberine/phytate salt (BPA) is successfully synthesized and aggregated in polyvinyl alcohol (PVA) film to impart fluorescent and photodynamic antimicrobial properties. Compared to berberine hydrochloride (BHL), BPA exhibited stronger fluorescence because intramolecular motions and intermolecular π–π accumulation of BHL are restricted by phytic acid (PA). Molecular dynamics simulation indicate that aggregation of BHL and PA formed through electrostatic interactions in the PVA matrix due to the change of the binding energy during the drying process. With increasing BPA content, the films exhibited increased ultraviolet, water vapor, and oxygen barriers and fluorescent properties, but reduced tensile strength and elongation at break. After radiated, PVA‐BPA9 film showed the highest antimicrobial rates against Staphylococcus aureus, Escherichia coli, P. citrinum, and Aspergillus niger reached 100%, 100%, 86.14%, and 66.24%, respectively, due to the increased reactive oxygen species production. The total number of microbial colonies in cooked chicken and oranges packaged by PVA‐BPA9 film with irradiation ARE 87.54% and 29.21% of those by PVA film. The findings indicate a new and feasible strategy to obtain a green photodynamic‐mediated film for safe and effective food packaging.

Experimental study on mechanical and durability properties of concrete incorporating various polyvinyl alcohol fiber lengths and dosages

To inquire about the properties of concrete reinforced with polyvinyl alcohol (PVA) fiber (various fiber lengths and dosages), different experimental tests including mechanical property, cracking resistance, and chloride resistance were investigated. The overall performance of PVA fiber-reinforced concrete (FRC) was innovatively analyzed integrating mechanical indicators and crack resistance parameters. Furthermore, nuclear magnetic resonance (NMR) and scanning electron microscope (SEM) were selected to analyze the causes and mechanisms underlying the alterations in the performance of PVA-FRC. The experimental results demonstrate that the flexural strength, the crack resistance characteristic and chloride ion penetration resistance of PVA-FRC are significantly improved compared to ordinary concrete. Increasing fiber length plays a key role in flexural strength, compared with fiber dosage. Considering both mechanical properties and durability, PVA-FRC containing 0.25% volume fraction of 12 mm PVA fibers (F12-0.25) demonstrated optimal performance.

Transparent and Flexible Hierarchical Porous Structure of Polyvinyl Alcohol Aerogel: A Microstructure Study

Aerogels have gained increasing attention due to their unique properties since their introduction in 1932. Silica aerogel, one of the earliest and most advanced types, is known for its high transparency and excellent thermal insulation. However, its internal pearl-like structure makes it extremely brittle, which limits its practical applications. To address this, through multiple refinements in formulation and production techniques, we developed a novel Polyvinyl Alcohol (PVA) aerogel using an innovative one-step standing method. This method significantly reduces the gelling time compared to the freeze–thaw method and eliminates the need for refrigeration, making it a more environmentally friendly and sustainable process. The resulting one-step standing PVA aerogel features a hierarchical porous structure, remarkable transparency, improved strength, and enhanced thermal insulation. Mechanical tests demonstrated that the PVA aerogel produced by the one-step standing method exhibited a significantly higher Young’s modulus of 4.2596 MPa, surpassing that of silica, copper nanowire (Cu NM), and graphene aerogels. Additional tests, including transmittance and thermal analysis, further confirmed that the one-step standing PVA aerogel excels in both transparency and thermal insulation. This combination of improved mechanical performance and light transmission opens novel potential applications, such as drug delivery systems, where the aerogel’s pore structure can store drugs while maintaining strength and transparency.

Cyclic Performance of Reinforced Concrete Columns Strengthened with Basalt-Fibre-Reinforced Cementitious Matrix (BFRCM)

The purpose of this experimental investigation was to confirm whether the Basalt-Fibre-Reinforced Cement Matrix (BFRCM) effectively enhances the cyclic performance of columns made of reinforced concrete (RC). The BFRCM system, which comprises basalt fabric mesh reinforced with a cementitious matrix containing polyvinyl alcohol (PVA) fibre, has significant practical implications. In the testing phase, concrete and steel reinforcement were used to create RC column specimens, which were then strengthened with three, four, and five layers of BFRCM. The horizontal cyclic and constant axial loads were applied and tested to evaluate the performance of RC columns with and without strengthening. By improving the energy dissipation by approximately 9 to 32% and increasing stiffness by roughly 24 to 44%, the column specimen with three, four, and five layers of BFRCM performed better than the control specimen. Furthermore, incorporating short fibre into the matrix effectively improved the tensile properties of the FRCM systems and decreased the shrinkage-induced cracks. The increased stiffness indicates that the column with BFRCM has better structural strength because it can sustain higher loads with less deflection. The thorough comparative analyses examined the RC column specimens’ failure modes, hysteretic responses, stiffness degradation, and energy dissipation, providing a reliable basis for the conclusions. The test results confirmed that the BFRCM effectively enhanced the seismic capabilities and has been promised a way to strengthen RC elements, providing valuable insights for civil engineering and materials science.

In-situ Forming Multipolymeric Glucose-Responsive Hydrogels.

Stimuli-responsive hydrogels (HGs) have shown promise for smart drug delivery applications. Specifically, glucose-responsive HGs having phenylboronic acid (PBA) functional groups are extensively pursued for insulin delivery in hyperglycemia. Current polymeric glucose-responsive HGs are cumbersome to fabricate and show a limited insulin release profile. Herein, we develop a straightforward fabrication of glucose-responsive multipolymer HGs (MPHGs) using a three-component in situ mixing. Molecular cargo, such as insulin, was loaded during the gelation. Heterobifunctional formylphenylboronic acid (FPBA) crosslinkers were used to interconnect polyvinyl alcohol (PVA) and branched polyethyleneimine (PEI) via boronate ester and imine bonds, respectively. Three positional isomers of FPBA (2FPBA, 3FPBA, and 4FPBA) resulted in HGs with distinct viscoelastic behaviors under the same conditions. HGs derived from 4FPBA exhibited more solid-like properties compared to 2FPBA and 3FPBA due to a higher crosslinking density. All the HGs exhibited glucose-responsive dissolution and release of embedded insulin cargo without disrupting the native structure. Insulin release profiles show a higher glucose-responsive release from 4FPBA-derived MPHGs. All the HGs were injectable, self-healing, and noncytotoxic below 10 μg/ml concentrations. The MPHGs developed in this study uncover new directions in creating glucose-responsive matrices for self-regulating drug delivery applications. In the future, detailed in vivo studies will be performed for clinical applications.

Development of Polymer Composite Membrane Electrolytes in Alkaline Zn/MnO2, Al/MnO2, Zinc/Air, and Al/Air Electrochemical Cells

This paper reports on the novel composite membrane electrolytes used in Zn/MnO2, Al/MnO2, Al/air, and zinc/air electrochemical devices. The composite membranes were made using poly(vinyl alcohol), poly(acrylic acid), and a sulfonated polypropylene/polyethylene separator to enhance the electrochemical characteristics and dimensional stability of the solid electrolyte membranes. The ionic conductivity was improved significantly by the amount of acrylic acid incorporated into the polymer systems. In general, the ionic conductivity was also enhanced gradually as the testing temperature increased from 20 to 80 °C. Porous zinc gel electrodes and pure aluminum plates were used as the anodes, while porous carbon air electrodes or porous MnO2 electrodes were used as the cathodes. The cyclic voltammetry properties and electrochemical impedance characteristics were investigated to evaluate the cell behavior and electrochemical properties of these prototype cells. The results showed that these prototype cells had a low bulk resistance, a high cell power density, and a unique device stability. The Al/MnO2 cell achieved a density of 110 mW cm−2 at the designated current density for the discharge tests, while the other cells also exhibited good values in the range of 70–100 mW cm−2. Furthermore, the Zn/air cell consisting of the PVA/PAA = 10:5 composite membrane revealed an excellent discharge capacity of 1507 mAh. This represented a very high anode utilization of 95.7% at the C/10 rate.