Synthesis of water-soluble perylenediimide-functionalized polymer through esterification with poly(vinyl alcohol)

Enhancing Polyvinyl Alcohol Nanocomposites with Carboxy-Functionalized Graphene: An In-Depth Analysis of Mechanical, Barrier, Electrical, Antibacterial, and Chemical Properties

To enhance the various properties of polyvinyl alcohol (PVA), varying concentrations of carboxy-functionalized graphene (CFG) were employed in the preparation of CFG/PVA nanocomposite films. FTIR and XRD analyses revealed that CFG, in contrast to graphene, not only possesses carboxylic acid group but also exhibits higher crystallinity. Mechanical testing indicated a notable superiority of CFG addition over graphene, with optimal mechanical properties such as tensile and yield strengths being achieved at a 3% CFG concentration. Relative to pure PVA, the tensile strength and yield strength of the composite increased by 2.07 and 2.01 times, respectively. XRD analysis showed distinct changes in the crystalline structure of PVA with the addition of CFG, highlighting the influence of CFG on the composite structure. FTIR and XPS analyses confirmed the formation of ester bonds between CFG and PVA, enhancing the overall performance of the material. TGA results also demonstrated that the presence of CFG enhanced the thermal stability of CFG/PVA nanocomposite films. However, analyses using scanning electron microscopy and transmission electron microscopy revealed that a 3% concentration of CFG was uniformly dispersed, whereas a 6% concentration of CFG caused aggregation of the nanofiller, leading to a decrease in performance. The incorporation of CFG significantly enhanced the water vapor and oxygen barrier properties of PVA, with the best performance observed at a 3% CFG concentration. Beyond this concentration, barrier properties were diminished owing to CFG aggregation. The study further demonstrated an increase in electrical conductivity and hydrophobicity of the nanocomposites with the addition of CFG. Antibacterial tests against E. coli showed that CFG/PVA nanocomposites exhibited excellent antibacterial properties, especially at higher CFG concentrations. These findings indicate that CFG/PVA nanocomposites, with an optimized CFG concentration, have significant potential for applications requiring enhanced mechanical strength, barrier properties, and antibacterial capabilities.

Starch-Capped Silver Nanoparticles Impregnated into Propylamine-Substituted PVA Films with Improved Antibacterial and Mechanical Properties for Wound-Bandage Applications

This research endeavor aims to develop polyvinyl alcohol (PVA) based films capable of blends with silver nanoparticles (Ag-NPs) for improved antibacterial properties and good mechanical strength to widen its scope in the field of wound dressing and bandages. This study reports synthesis of propylamine-substituted PVA (PA-PVA), Ag-NPs via chemical and green methods (starch capping) and their blended films in various proportions. Employment of starch-capped Ag-NPs as nanofillers into PVA films has substantially improved the above-mentioned properties in the ensuing nanocomposites. Synthesis of PA-PVA, starch-capped Ag-NPs and blended films were well corroborated with UV/Vis spectroscopy, FTIR, NMR, XRD and SEM analysis. Synthesized Ag-NPs were of particle shape and have an average size 20 nm and 40 nm via green and chemical synthesis, respectively. The successful blending of Ag-NPs was yielded up to five weight per weight into PA-PVA film as beyond this self-agglomeration of Ag-NPs was observed. Antibacterial assay has shown good antimicrobial activities by five weight per weight Ag-NPs(G)-encapsulated into PA-PVA blended film, i.e., 13 mm zone inhibition against Escherichia coli and 11 mm zone inhibition against Staphylococcus aureus. Physical strength was measured in the terms of young's modulus via tensile stress-strain curves of blended films. The five weight per weight Ag-NPs(G)/PA-PVA blend film showed maximum tensile strength 168.2 MPa while three weight per weight Ag-NPs(G)/PVA blend film showed highest values for ultimate strain 297.0%. Ag-NPs embedment into PA-PVA was resulted in strong and ductile film blend than pristine PA-PVA film due to an increase in hydrogen bonding. These good results of five weight per weight Ag-NPs(G)/PA-PVA product make it a potent candidate for wound dressing application in physically active body areas.

Clinical Chemistry Route for Investigation of Alzheimer's Disease: A Label-Free Electrochemiluminescent Biosensor for Glycogen Synthase Kinase-3 Beta

Herein, we report a novel label-free electrochemiluminescent (ECL) biosensor for the detection of glycogen synthase kinase-3 beta (GSK-3β). A simple and feasible sensor was prepared by a two-step process. A polymeric coordination layer of phosphorylated poly vinyl with Zr⁴⁺ was used as the sensory hosting matrix because it efficiently formed a complex. The exterior Zr⁴⁺ can further combine with another phosphate through coordination, and GSK-3β catalyzes the phosphorylation of protein molecules. Thus, the biosensor can detect GSK-3β using luminol as an ECL probe. The ECL intensity of the proposed sensor responded proportionally to the concentration of GSK-3β under direct immersion mode with a linear response in a logarithmic scale over the wide range from 0.5 to 91.5 ng L^-1 and a detection limit of 0.055 ng L^-1. Excellent selectivity, stability, and reproducibility were achieved using the prepared biosensor, which has a simple preparation, low cost, and disposable suitability. This work aims to provide a novel tool for early diagnosis and pathological mechanism exploration about AD by detecting inchoate change of GSK-3β content in body fluid, thus to precaution the risk of Alzheimer's disease. It is of great importance for clinical chemistry for the investigation of Alzheimer's disease.

Remarkable enhancement of ambient-air electrical conductivity of the perylenediimide π-stacks isolated in the flexible films of a hydrogen-bonded polymer

N,N′-di(2-(trimethylammoniumiodide)ethylene) perylenediimide (TAIPDI), forming extensive π-stacks through the strong π–π interactions of large π-planes, was isolated in the hydrogen-bonding milieu of polyvinyl alcohol (PVA) from aqueous solutions.