Hydroxyl Groups Of PVA Research Articles

Comparison of permeability of topical Cream drug through polymer synthetic membranes of different structures using Franz Cell diffusion test

In this study, in-vitro release experiments were performed using a Franz Diffusion Cell system for Terbinafine Hydrochloride, which is used in the treatment of various fungal infections in the skin caused by many susceptible dermatophytes. In order to evaluate TH transdermally, it was aimed to compare the permeability between polymeric membranes synthesized with polyvinyl alcohol and chitosan mixtures and commercial membranes. In the transdermal drug delivery system calculations, the Fick Diffusion Law was modified and the obtained data were compared. The study was evaluated according to the USP <1724> topical drug products in semisolid form - performance tests. A new high-performance liquid chromatography method was validated for the assay of TH released into the receptor medium in accordance with the ICH guideline. According to the results obtained during the validation process, the limit of detection value was calculated as 0.005 µg/mL and the limit of quantification value was 0.013 µg/mL. Since polymer-based synthetic membranes provide permeability according to molecular size, properties and the ideal environment for measuring and analyzing the diffusion rate of a compound, in experiments conducted using membranes of different structures, the permeability profiles of selected polymer synthetic membranes were statistically evaluated. It has been noted that the hydroxyl groups in PVA and the hydrophilic CS-g-PNDMAAm graft copolymer act at varying rates to enhance or reduce the permeability across the membrane by promoting its diffusion. NaY zeolite has been shown to function as an adsorbent against the medication, lessening the impact of hydrophilic PVA without supplying permeability.

Exploring the AC conductivity and dielectric properties of PVA films doped with Erythrosin B

Erythrosin B (EB) doped in PVA film was processed utilizing the casting procedure, and the structure was investigated via the Fourier Transformation infrared technique (FTIR). FTIR analysis presented a strong formation of intermolecular hydrogen bonds among PVA and EB hydroxyl groups (OH). Characteristic temperature and frequency variation of dielectric behavior and AC electrical conductivity for films of PVA doped with Erythrosin B were analyzed at (293–383 K) temperature and (102–106 Hz) frequency. The AC conductivity dependency indicates that the predominant conduction mechanism in PVA doped with Erythrosin B films follows the correlated barrier hopping (CBH) model. The charge carriers’ hopping involving localized states causes a relaxation process. Estimates were made for the AC conductivity activation energy and the conductivity relaxation energy. Frequency and temperature affect the dielectric constant (ε′) and the dielectric loss (ε″). The complex impedance spectrum (Z′ versus Z″) showed single semicircular arcs with a decreased radius with increasing temperature. The relaxation peaks in the electric modulus representation are clearly defined, and the relaxation period has been calculated.

PH-Responsive Degradable Electro-Spun Nanofibers Crosslinked via Boronic Ester Chemistry for Smart Wound Dressings.

Recent advances in the treatment of chronic wounds have focused on the development of effective strategies for cutting-edge wound dressings based on nanostructured materials, particularly biocompatible poly(vinyl alcohol) (PVA)-based electro-spun (e-spun) nanofibers. However, PVA nanofibers need to be chemically crosslinked to ensure their dimensional stability in aqueous environment and their capability to encapsulate bioactive molecules. Herein, a robust approach for the fabrication of pH-degradable e-spun PVA nanofibers crosslinked with dynamic boronic ester (BE) linkages through a coupling reaction of PVA hydroxyl groups with the boronic acid groups of a phenyl diboronic acid crosslinker is reported. This comprehensive analysis reveals the importance of the mole ratio of boronic acid to hydroxyl group for the fabrication of well-defined BE-crosslinked fibrous mats with not only dimensional stability but also the ability to retain uniform fibrous form in aqueous solutions. These nanofibers degrade in both acidic and basic conditions that mimic wound environments, leading to controlled/enhanced release of encapsulated antimicrobial drug molecules. More importantly, drug-loaded BE-crosslinked fibers show excellent antimicrobial activities against both Gram-positive and Gram-negative bacteria, suggesting that this approach of exploring dynamic BE chemistry is amenable to the development of smart wound dressings with controlled/enhanced drug release.

Cross-linked poly(vinyl alcohol)/citric acid electrospun fibers containing imidazolium ionic liquid with enhanced antiadhesive and antimicrobial properties

Patients in hospital environments are susceptible to bacterial colonization, which can lead to infections. In this study, electrospun fibers were manufactured using poly(vinyl alcohol) (PVA) crosslinked with citric acid (CA) and incorporating the ionic liquid (IL) 1-hexadecyl-3-methylimidazolium chloride (C16MImCl) to prevent microbial growth and biofilm formation. The presence of CA and IL reduced the surface tension of the PVA solution (12% w/v) from 52.07 mN/m to 35.84 mN/m. CA was introduced into PVA solutions, and the resulting fibers were thermally crosslinked through esterification between PVA hydroxyl groups and CA. X-ray photoelectron spectroscopy (XPS) confirmed the presence of IL on the fiber surfaces. The IL acted as a surfactant, imparting plasticity to the electrospun fibers and enhancing homogeneity and mechanical properties. Before crosslinking, the PVA/CA/IL fibers exhibited an elongation at break (%) of approximately 140%, a tensile strength of 5.3 MPa, and an elastic modulus of 18.2 MPa. After cross-linking, the elongation at break reduced to 86%, the tensile strength increased to 7.6 MPa, and the elastic modulus increased to 88 MPa. Mechanical measurements confirmed the thermal crosslinking of the fibers, primarily because of the increased elastic modulus. Adhesion and proliferation tests with Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) indicated reduced bacterial adhesion and growth on the PVA/CA/IL fibers. Antimicrobial assays further confirmed a 50.73% and 69.42% increase in bactericidal activity against S. aureus and P. aeruginosa, respectively. The PVA/CA/IL fibers exhibit promising potential for producing antimicrobial materials to prevent the attachment and proliferation of microbial strains on solid surfaces.

Macroporous polyvinyl alcohol-formaldehyde-silicon composite sponges with designed structure for high-efficiency water-in-oil emulsion separation

Macroporous materials with suitable pore structure and surface composition have demonstrated their advancing applications in absorption, adsorption, and separation. In this contribution, two types of macroporous polyvinyl alcohol-formaldehyde (PVFs) based composite sponges, stearoyl chlorides modified polyvinyl alcohol/PVF (PVA/PVF-CH) and octadecyltrimethoxysilane modified PVA/PVF (PVA/PVF-Si) are designed and synthesized through the secondary crosslinking reaction between the hydroxyl groups in PVA and PVF with formaldehyde, and subsequently covalently bonding the long-alkyl chains into the network of the composite sponge. Basic characterizations confirm PVA/PVF-CH and PVA/PVF-Si composite sponges exhibit the open-cell structure as original PVFs with porosity up to 80.1%, hydrophobic networks, and narrow pore size distribution (5 µm to 60 µm). Notably, the PVA/PVF-Si, possessing the smallest average pore size (14.4 µm), exhibits ignorable swelling performances in a wide range of organic solvents and excellent mechanical properties and separation properties for oil from water-in-oil emulsion with separation efficiency and flux up to 99.99% and 7.65 × 104 L m−2h−1bar−1 as compared to PVA/PVF-CH, respectively. Those features indicate that PVA/PVF-Si composite sponges can be desirable for emulsion separation.

Role of high hydrostatic pressure pretreatment on the formation of electrospun nanofibers from soy protein isolate/polyvinyl alcohol

In this research, the characteristics of the high hydrostatic pressure (HHP)-treated soy protein isolate (SPI) solutions as well as HHP-treated SPI (HSPI) electrospun fibers were comprehensively studied for the first time. For this purpose, surface tension, electrical conductivity, viscosity, zeta potential, and secondary structure of HSPI solutions at different ratios were investigated. Also, differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) of HHP-treated and non-treated SPI: PVA nanofibers were thoroughly compared. HHP denaturation reduced the size of nanofibers by 50–100 nm, diminished ordered structures and crystallinity of nanofibers, increased their melting point and induced hydrogen bonding between amino groups of denatured SPI and hydroxyl groups of PVA. These findings open a new horizon in the successful application of non-thermal energies in the electrospinning process to achieve appropriate fibers at nanoscale.

Facile preparation of biocompatible and antibacterial water-soluble films using polyvinyl alcohol/carboxymethyl chitosan blend fibers via centrifugal spinning

Water-soluble polyvinyl alcohol/carboxymethyl chitosan (PVA/CMCS) blend fiber films were successfully prepared using a plane-collection centrifugal spinning machine. The addition of CMCS significantly increased the shear viscosity of the PVA/CMCS blend solution. The effects of spinning temperature on the shear viscosity and the centrifugal spinnability of PVA/CMCS blend solution were discussed. The PVA/CMCS blend fibers were uniform, and their average diameters ranged from 1.23 μm to 29.01 μm. It was found that the CMCS was distributed evenly in the PVA matrix and increased the crystallinity of PVA/CMCS blend fiber films. The hydrogen bonds between the hydroxyl group of PVA and the carboxymethyl group of CMCS were also detected. An in vitro cell study of human skin fibroblast cells on the PVA/CMCS blend fiber films confirmed biocompatibility. The maximum tensile strength and elongation at break of PVA/CMCS blend fiber films could reach 3.28 MPa and 29.52 %, respectively. The colony-plate-count tests indicated that the PVA16-CMCS2 presented 72.05 % and 21.36 % antibacterial rates against Staphylococcus aureus (104 CFU/mL) and Escherichia coli (103 CFU/mL), respectively. These values indicated that the newly prepared PVA/CMCS blend fiber films are promising materials for cosmetic and dermatological applications.

UV-cured polyvinyl alcohol-MXene mixed matrix membranes for enhancing pervaporation performance in dehydration of ethanol

In this study, Ti3C2Tx MXene nanosheets were synthesized and loaded into UV-curable acrylate polyvinyl alcohol (APVA) to fabricate a novel APVA-MXene mixed matrix membrane (MMM) for ethanol dehydration by pervaporation (PV) process. UV-curable APVA was synthesized by substituting the hydroxyl groups of PVA with the methacryloyl groups of glycidyl methacrylate (GMA). A rapid and energy-efficient method for fabricating the active layer was achieved by UV-crosslinking of APVA over a 2-min period. The morphology, crystal structure, chemical composition, and thermo-mechanical properties of the membranes were investigated by FESEM, XRD, FTIR, TGA, and static mechanical stretching. Incorporating MXene nanosheets into the APVA matrix resulted in an increase in permeation flux and separation factor for APVA-MXene MMMs due to its laminated structure with interlayer transport channels of two dimensions, excellent compatibility with the polymer matrix, and high surface hydrophilicity. When the MXene loading reached 3 wt%, the optimal separation performance was achieved with a permeation flux of 942 g/(m2.h) (increased by 106% compared to pristine APVA membranes) and a separation factor of 294 (increased by 79% compared to pristine APVA membranes).

γ-irradiation induced effects on structural, morphological and photoluminescence properties of PEO-PVA blended polymer films

PEO/PVA blends have been prepared to investigate the effect of gamma rays on the structural, morphological and photoluminescence properties. The studies of non-irradiated and irradiated samples with radiation doses of 10 kGy were examined by using XRD, ATR-FTIR, Optical microscopy and PL. Gamma photons induced important chemical rearrangements, especially by PVA hydroxyl groups. We found that the crystallinity rate is strongly influenced by radiation. In this context, one could predict that the immiscibility of PVA with PEO and the interactions between the chains are of the electrostatic type. A structural-scale disturbance due to the radical formation leads to spherulitic texture modifications of the PEO. Due to the luminescence properties, the blend samples behave like core-shell nanoparticles. This phenomenon is due to the fact that the PVA polymer played the role of shell. Irradiation makes it possible to obtain well-ordered spherulites and to get a high pore density. The irradiated blend showed a higher quantum yield. The significant chemical and morphological changes caused by gamma radiation favored the optical recombination of hydroxyl groups.

Plasticizing effect of 1‐butyl‐3‐methylimidazolium bromide content on poly(vinyl alcohol)

AbstractPVA/IL composites were successfully prepared with an ionic liquid (IL), 1‐butyl‐3‐methylimidazolium bromide and poly(vinyl alcohol) (PVA). The plasticizing effect of IL on PVA was investigated using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), X‐ray diffraction (XRD), thermogravimetric analysis (TGA) and melt flow index (MI) measurements. FTIR analysis indicated that the anion (Br−) of IL could form hydrogen bonds with the hydroxyl groups of PVA. With an increase of IL, –OH absorption peaks of PVA/IL composites shifted to higher wavenumbers. DSC analysis showed that both melt and crystallization temperatures of the PVA/IL composites decreased as IL content increased. XRD analysis showed that the degree of crystallinity of the PVA/IL composites had a decreasing trend with an increase of IL. TGA showed that IL could effectively improve the thermal stability of PVA. The thermal stability of the PVA/IL composites decreased gradually with increasing IL content, but was higher than that of PVA. Thermal processing window (ΔT) analysis indicated that the addition of IL could significantly broaden ΔT of the PVA/IL composites, and their ΔT values first remained basically unchanged and then increased slightly with an increase of IL. In addition, MI analysis presented that the melt processability of the PVA/IL composites was not improved with the addition of IL and it was gradually improved with increasing IL content. In this work, PVA/IL composites with wide ΔT and high melt flow properties were prepared, which will lay a solid foundation for the preparation of high‐performance PVA fibers by melt spinning. © 2022 Society of Industrial Chemistry.

Performance relative study of metal oxide nanoparticles on mechanical, thermal, and optical characteristics of gamma‐irradiated poly (vinyl alcohol) nanocomposites

Nanocomposites based on poly (vinyl alcohol) (PVA) filled with different types of nanometal oxides named MgO, Al2O3, and CuO were attained from an aqueous solution of PVA. PVA/nanometal oxide films were achieved by the solution casting procedure. The prepared nanocomposites were subjected to a gamma radiation dose at 50 kGy to study the impact of ionizing radiation on the various properties of the prepared samples. In this context, this work was mainly concerned with the differences in the behavior of various metal oxides, as well as the effect of ionizing radiation on the tensile strength (TS), elongation at break (E%), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X‐ray diffraction, and optical characteristics of the fabricated specimens. Furthermore, Fourier transform infrared (FTIR), SEM, and thermodynamic factors (Ea, ΔH, ΔG, and ΔS) were considered. FTIR and the suggested reaction mechanism supported that the hydroxyl groups of PVA have a really strong affinity to form charge‐transfer complexes with different nanometal oxides done chelation. In general, the interference of 0.1% of all studied nanometal oxides improved TS, thermal stability, melting temperature, and optical properties of PVA, whereas PVA/0.1 CuO was the best. Moreover, gamma radiation exposure enhanced the different properties of native PVA and displayed anisotropic behavior toward its nanocomposites.

Fabrication of electrospun Mondia whitei/PVA nanofibres: application in the removal of acidic drugs

Novel electrospun Mondia whitei/PVA blend nanofibres were fabricated for potential water treatment applications by blending a natural polymer extracted from Mondia whitei (MW) roots with poly (vinyl alcohol) (PVA). The fabricated nanofibres were shown to have a smooth and uniform morphology with an average diameter of 99 ± 0.025 nm. The FTIR, XPS, XRD, and TGA characterisation results indicated changes in functional groups, crystallinity, and thermal stability of the Mondia whitei/PVA blend nanofibres, as compared to the original material. This finding confirmed that the polymers interacted through hydrogen bonding of MW and hydroxyl groups of PVA. The performance of the fabricated nanofibres was investigated for the removal of acidic drugs from spiked water samples. Factors (concentration of acidic drugs, dosage of the nanofibers and contact time) which affect the removal efficiency of the nanofibres were optimised using ultrapure water. Using the nanofibres, 100% removal efficiency for acidic drugs (aspirin, ketoprofen, fenoprofen, diclofenac, and ibuprofen) was achieved. The removal efficiency of the influent wastewater was 76, 89, 97, 93 and 94% for aspirin, ketoprofen, fenoprofen, diclofenac and ibuprofen, respectively, while the removal efficiency of the effluent was 86, 96, 97, 97 and 95% for aspirin, ketoprofen, fenoprofen, diclofenac and ibuprofen, respectively.

Electrospun PVA/α‐mangostin nanofibers, their anti‐bacterial ability and anti‐oxidation performances

Abstractα‐mangostin which has been extracted from mangosteen peel is known as an excellent bioactive substance with high anti‐oxidation, anti‐bacterial, anti‐inflammatory, etc. The application of α‐mangostin in the biomedicine field is potential and promising. However, the α‐mangostin has a poorly solubility in aqueous. Using polymers as carriers to improve the solubility of α‐mangostin has been attracted in research. In this work, poly(vinyl alcohol) (PVA) crosslinked with citric acid has been used as a carrier to enhance the solubility of α‐mangostin. The PVA/α‐mangostin nanofibers were prepared by electrospinning method with the ratio of PVA/α‐mangostin varied 100/0, 100/1 and 100/3 (w/w). The obtained PVA/α‐mangostin nanofibers have smooth and homogenous surface. The introduction of α‐mangostin into PVA can increase mechanical properties of PVA. The slight shift in wavenumbers characterized for stretching vibration of hydroxyl groups in the PVA/α‐mangostin nanofibers as compared to PVA nanofibers suggested that hydroxyl groups in PVA can interact with hydroxyl groups in α‐mangostin. The solubility of α‐mangostin in ethanol/pH buffer solutions was enhanced significantly in the presence of PVA. The antibacterial and anti‐oxidation ability of PVA/α‐mangostin nanofibers was increased as increasing α‐mangostin concentration. These results showed that the nanofibers are potential for application in biomedicine field as a wound dressing material or in food industry.

Investigation of Mechanical Properties in PVA Hydrogels Due to Cation Interactions Described by Reactive Forcefield Based Molecular Dynamics Simulations

Hydrogels are cross-linked networks containing water and are widely used in multiple fields due to their intrinsic softness and diffusive properties. One field of particular interest is in medical devices and tissue and organ engineering. Poly(vinyl alcohol) (PVA) is one common hydrogel where its mechanical properties can be changed by using different salt solutions, making it more appropriate for certain applications, such as artificial neuron tissue. In this study, we used the ReaxFF reactive forcefield to investigate PVA in lithium and potassium chloride. It was hypothesized that lithium might promote a proton transfer from the PVA hydroxyl groups, therefore inhibiting the PVA from forming hydrogen bonds with itself, yielding a weaker PVA hydrogel. Conversely, potassium would not promote a proton transfer, instead getting inside the PVA structure, allowing a higher density of hydrogen bonds to form, creating a stronger PVA hydrogel. We were able to show a proton transfer was favorable in the lithium case and unfavorable in the potassium case. This explains the differences in mechanical properties shown in experimental results and provides atomistic detail to motivate tunable mechanical properties in PVA hydrogels in various salt solutions.

Polymer-Induced Emission-Active Fluorine-Embedded Carbon Dots for the Preparation of Warm WLEDs with a High Color Rendering Index.

Exploration of many strategies has continuously contributed to producing aggregation-induced red-emissive carbon dots (CDs). In this work, we designed fluorine-embedded (F-embedded) CDs from 1,2,4-triaminobenzene, thiourea, and ammonium fluoride (NH4F) exhibiting polymer-induced emission (PIE). The PIE phenomenon of fluorescent CDs is obtained in poly(vinyl alcohol) (PVA), showing emissions at 611 and 617 nm in the dispersed and solid states, respectively. The CDs exhibited a red shift of 28 nm in the PVA solution because PVA hydroxyl groups formed a robust bridge-like H-bonding network between CDs. The fluorine embedded in CDs enhanced the H-bond affinity toward PVA. It showed that this H-bond restricted the coupling of CDs' surface states and inhibited the nonirradiation transfer. For the solid state, surface PVA chains eliminated the π-π interaction of the conjugated core and constructed a self-quenching resistance polymeric system around CDs. As a result, CDs showed an unexpected red shift of fluorescence emission in PVA. Furthermore, white light-emitting diodes (WLEDs) have a correlated color temperature (CCT) of 5232 K, and a high color rendering index of 95 has been fabricated by integrating the red- and green-emissive films over the UV LEDs. Interestingly, the as-synthesized CDs showed room temperature phosphorescence (RTP), which enabled us to employ the CDs in double-security protection. Simultaneously, CDs have been used in fingerprint detection.

Luminescent composite organohydrogels with Fe3+, pH, and glucose-dependent shape memory behavior accompanied with diverse fluorescence variation

It is quite urgent to develop a smart and high through-put confidential information storage, protection, and display platform based on the fluorescent hydrogels that could exhibit diverse fluorescent variation behavior during each stimulus-based shape memory and recovery process. Herein, it proposed an effective approach to develop a novel fluorescent composite gel with Fe3+, pH, and glucose-dependent diversity fluorescence variation and shape memory behavior. For this composite gel system, based on the reversible coordination interactions between Fe3+ and carboxylic acid groups of carboxymethyl cellulose (CMC), boric acid groups of carbon dots (CDs), and hydroxyl groups of PVA, it can stabilize and memorize the temporary shapes under the stimulus of Fe3+ and pH, respectively. Meanwhile, the fluorescence of the CDs within the gels can also exhibit diversity variation behaviors during each shape recovery process. Furthermore, the compositions of the composite gel were optimized to realize relatively high efficiency of shape recovery and fluorescence variation under each type of stimulus. In summary, this study presented a universal strategy for multi-shape memory hydrogels with diverse fluorescence variation properties which exhibited prominent prospective in the field of information encryption with high-level security.

Surface Functionalization of Polymer Particles for Cell Targeting by Modifying Emulsifier Chemistry.

The oil in water emulsion/solvent extraction method is used to fabricate many FDA approved, polymer particle formulations for drug delivery. However, these formulations do not benefit from surface functionalization that can be achieved through tuning particle surface chemistry. Poly(vinyl alcohol) (PVA) is the emulsifier used for many FDA approved formulations and remains associated with the particle surface after fabrication. We hypothesized that the hydroxyl groups in PVA could be conjugated with biomolecules using isothiocyanate chemistry and that these modifications would endow the particle surface with additional functionality. We demonstrate that fluorescein isothiocyanate and an isothiocyanate derivatized mannose molecule can be covalently attached to PVA in a one-step reaction. The modified PVA polymers perform as well as unmodified PVA in acting as an emulsifier for fabrication of poly(lactide-co-glycolide) particles. Particles made with the fluorescein modified PVA exhibit fluorescence confined to the particle surface, while particles made with mannose modified PVA bind concanavalin A. In addition, mannose modified PVA increases particle association with primary macrophages by three-fold. Taken together, we present a facile method for modifying the surface reactivity of polymer particles widely used for drug delivery in basic research and clinical practice. Given that methods are established for conjugating the isothiocyanate functional group to a wide range of biomolecules, our approach may enable PVA based biomaterials to engage a multitude of biological systems.

The influence of ZnO nanoparticles on the structural, optical and dielectric properties of Polyvinyl alcohol films

Polyvinyl alcohol/Zinc oxide (PVA/ZnO) nanocomposite films with various weight percentages of ZnO nanoparticles (0 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%) were prepared by solution casting method. The structural, optical and morphological properties of the synthesized samples were characterized by X-ray diffraction (XRD), UV–Visible spectroscopy, Fourier transform Infrared spectroscopy (FTIR) and Scanning electron microscope (SEM). X-ray diffraction studies confirms the formation of PVA/ZnO nanocomposites. From the UV–vis absorbance spectra, the band gap energy of the samples was calculated and its value decreases with increasing the wt% of ZnO into the PVA matrix. The transmittance of the nanocomposites in the visible region is decreased with increasing the concentration of ZnO into the PVA matrix and completely blocked in the UV region. These behaviours suggests that the nanocomposite materials could be used as UV shielding materials. The FTIR analysis indicates physical interaction between hydroxyl group of PVA and ZnO. SEM shows the dispersion of ZnO on the surface of PVA matrix. The dielectric properties and AC conductivity measurement in the frequency range 100 Hz to 1 MHz reveals the maximum dielectric constant at PVA/5 wt% ZnO nanocomposite.

Performance enhanced triboelectric nanogenerator by taking advantage of water in humid environments

Improving the performance of triboelectric nanogenerator (TENG) in environment with high humidity is critical for their applications in blue energy, humidity sensing, implantable nanodevice etc. Here, we report a kind of humidity-resisting TENG (HR-TENG) by using polyvinyl alcohol/lithium chloride (PVA/LiCl) as the triboelectric layer, the output of which is much enhanced (~5 times) with the increase of relative humidity (RH, from 20% to 99%). Abundant hydroxyl groups in PVA can fix water molecules to form more tribo-positive surface polarity, and LiCl can regulate the water absorption ability of PVA/LiCl film. The combined effect brings in numbers of wrinkle microstructure on its surface and synchronously decreases its modulus, enabling more efficient contact. Charge density of the HR-TENGs are higher than 115 μC/m2 in a wide range of RH (from 60% to 99%), especially, reaches a maximum value of 244 μC/m2 in 90% RH, which is much larger than the highest value 110 μC/m2 among reported HR-TENGs (RH>50%). Moreover, the PVA/LiCl based TENGs can be acted as power source in high RH (93%) condition and respiratory monitoring sensor for human physiological monitoring. These results provide an efficient way for TENG with high output in high humidity environments.

Obtaining of Mesoporous Aluminosilicates with High Hydrothermal Stability by Composite Organic Templates: Utility and Mechanism.

We have reported the synthesis of mesoporous aluminosilicates (MAs) with high hydrothermal stability via assembly of basic characteristic structure units of typical microporous zeolite Y. In spite of this, high consumption of organic template and H2O remains a major obstacle to its industrial application. Herein, a facile and effective strategy called "composite templates" was employed to decrease significantly the amount of P123 and H2O. In this method, composite micelles of P123/poly(vinyl alcohol) (PVA) could be more easily dispersed in the solution due to the lowering of water's surface tension caused by the free hydroxyl groups of PVA. Moreover, the improved assembly ability of composite micelles in high concentration solution leads to the synthesis of hydrothermally stable MAs with 45% decrease of organic template P123 and 81% that of water amount. It was found that by the introduction of composite templates, the textural properties such as the surface area of materials, volume of pore, size of pore, and thickness were enlarged simultaneously. Meanwhile, this article presented an understanding into the assembly of composite micelles in the process of synthesis of MAs.