Preparation of PVA-GA-CS/PVA-Fe-SA bipolar membrane and its application in electro-generation of 2,2-dimethyl-3-hydroxypropionic acid

Interpenetrating Composite Hydrogel Electrolyte with Organic/Inorganic Polar Groups for Stable Zinc Metal Anode

Hydrogel electrolytes have been widely explored in flexible zinc batteries owing to their considerable mechanical strain and water-retaining properties. However, it is difficult to balance the contradiction between the ionic conductivity and the mechanical strength due to the deterioration of structural stability with the addition of electrolyte salts. To address this, we designed a coassembling organic-inorganic hydrogel (P-P/M) based on poly(vinyl alcohol)-polyacrylamide (P-P) interpenetrating matrix decorated with Zn-based montmorillonite (Zn-MMT). The Zn-MMT with overall negative potential can attract and regulate the transport of Zn2+, while the Brønsted/Lewis acid sites with positive polarizations offer anchoring sites for anions, which increases the cation transference number and reduces byproduct formation. Moreover, the formation of hydrogen bonds in the hydrogel can weaken the contact between free water molecules and the zinc cations, which effectively suppresses the corrosion of zinc foil. Consequently, the Zn//Zn cell with P-P/M electrolyte delivers a long cycle life of 2400 h at 0.5 mA cm-2. The good mechanical properties of the P-P/M hydrogel boost its application in flexible pouch cells even under bending and cutting conditions. This study provides an effective approach to designing organic-inorganic hydrogel electrolytes for long-life flexible zinc batteries.

Antibacterial wound dressing with cross-linked electrospun surface from reduced graphene oxide doped polyvinyl alcohol/sodium caseinate blends

In this study, a new biomaterial with polyvinyl alcohol (PVA)/sodium caseinate (SodCa)/reduced graphene oxide (rGO) structure was developed. Antibacterial effective nanofibers were successfully produced by electrospinning method from 1%, 3%, 5%, and 7% rGO added PVA/SodCa (60:40, w:w) solution mixtures prepared for use as modern wound dressings. To create a usage area, especially in exuding wounds, hydrophilic PVA/SodCa/rGO electrospun mats were cross-linked by dipping them in a glutaraldehyde (GLA) bath. The surface micrographs of all nanofibers were homogeneous and smooth. rGO-doped biomaterials were obtained as thin nanofibers in the range of 301-348 nm. Nanofibers, which were completely soluble in water, after cross-linking preserved their existence in the range of 87%-81% at the end of the 24th hour in distilled water. It was reported that these biomaterials that persist in an aqueous environment show swelling behavior in the range of 275%-608%. The porosity of uncross-linked pure PVA/SodCa nanofibers increased by 46.75% after cross-linking. Moreover, the tensile strength of cross-linked PVA/SodCa electrospun mats increased in the presence of rGO. Provided that wound dressing is done every 24 h with 3% rGO-doped PVA/SodCa nanofiber and provided that wound dressing is done every 48 h with 5% rGO-doped PVA/SodCa nanofiber showed antibacterial activity against S. aureus as 99.38% and 99.55%, respectively.

Poly (vinyl alcohol)-alginate as potential matrix for various applications: A focused review

Advances in polymers have made significant contribution in diverse application oriented fields. Multidisciplinary applicability of polymers generates a range of strategies, which is pertinent in a wide range of fields. Blends of natural and synthetic polymers have spawned a different class of materials with synergistic effects. Specifically, poly (vinyl alcohol) (PVA) and alginate (AG) blends (PVAG) have demonstrated some promising results in almost every segment, ranging from biomedical to industrial sector. Combination of PVAG with other materials, immobilization with specific moieties and physical and chemical crosslinking could result in amendments in the structure and properties of the PVAG matrices. Here, we provide an overview of the recent developments in designing PVAG based matrix and complexes with their structural and functional properties. The article also provides a comprehensive outline on the applicability of PVAG matrix in wastewater treatment, biomedical, photocatalysis, food packaging, and fuel cells and sheds light on the challenges that need to be addressed. Finally, the review elaborates the future prospective of PVAG matrices in other unexplored fields like aircraft industry, nuclear science and space exploration.

Rapid spray-crosslinked assembly of a stable high-performance polyelectrolyte bipolar membrane

Rapid spray assembly coupled with chemical cross linking was used to prepare a stable high-performance polyelectrolyte bipolar membrane.

Fabrication and characterization of carboxymethyl chitosan/poly(vinyl alcohol) hydrogels containing alginate microspheres for protein delivery

In this research, a novel drug delivery system consisting of alginate microspheres and carboxymethyl chitosan/poly(vinyl alcohol) hydrogel was developed for prolonged and sustained controlled drug release. The alginate microspheres and various volume ratios of carboxymethyl chitosan were incorporated physically into poly(vinyl alcohol) to form the composite system. Scanning electron microscope, rheometer, differential scanning calorimetry, and thermogravimetric analysis were used to investigate the morphological, rheological, and thermal properties. The adsorptivity and hydrogel content were evaluated by swelling ratio and gel fraction, respectively. Incorporation of alginate microspheres improved the swelling ratio and thermal stability of carboxymethyl chitosan/poly(vinyl alcohol) hydrogel. Carboxymethyl chitosan decreased gel fraction and elasticity while increased swelling and porosity of hydrogel. In vitro, the release profiles of bovine serum albumin from the composite gels were sustained for 2 weeks in phosphate buffered saline.

Magnetic biodegradable Fe3O4/CS/PVA nanofibrous membranes for bone regeneration

In recent years, interest in magnetic biomimetic scaffolds for tissue engineering has increased considerably. The aim of this study is to develop magnetic biodegradable fibrous materials with potential use in bone regeneration. Magnetic biodegradable Fe(3)O(4)/chitosan (CS)/poly vinyl alcohol (PVA) nanofibrous membranes were achieved by electrospinning with average fiber diameters ranging from 230 to 380 nm and porosity of 83.9-85.1%. The influences of polymer concentration, applied voltage and Fe(3)O(4) nanoparticles loading on the fabrication of nanofibers were investigated. The polymer concentration of 4.5 wt%, applied voltage of 20 kV and Fe(3)O(4) nanoparticles loading of lower than 5 wt% could produce homogeneous, smooth and continuous Fe(3)O(4)/CS/PVA nanofibrous membranes. X-ray diffraction (XRD) data confirmed that the crystalline structure of the Fe(3)O(4), CS and PVA were maintained during electrospinning process. Fourier transform infrared spectroscopy (FT-IR) demonstrated that the Fe(3)O(4) loading up to 5 wt% did not change the functional groups of CS/PVA greatly. Transmission electron microscopy (TEM) showed islets of Fe(3)O(4) nanoparticles evenly distributed in the fibers. Weak ferrimagnetic behaviors of membranes were revealed by vibrating sample magnetometer (VSM) test. Tensile test exhibited Young's modulus of membranes that were gradually enhanced with the increase of Fe(3)O(4) nanoparticles loading, while ultimate tensile stress and ultimate strain were slightly reduced by Fe(3)O(4) nanoparticles loading of 5%. Additionally, MG63 human osteoblast-like cells were seeded on the magnetic nanofibrous membranes to evaluate their bone biocompatibility. Cell growth dynamics according to MTT assay and scanning electron microscopy (SEM) observation exhibited good cell adhesion and proliferation, suggesting that this magnetic biodegradable Fe(3)O(4)/CS/PVA nanofibrous membranes can be one of promising biomaterials for facilitation of osteogenesis.