Formation Of Silver Nanoparticles Research Articles

Analysis of Newtonian heating in fractional hybrid nanofluid with the influence of transverse magnetic field

This article deals with the effects of Newtonian heating in second grade Hybrid nanofluid. For memory effects the problem is modeled with the help of generalized Fourier law along with generalized boundary conditions. A hybrid nanofluid model is used with nano particles of the form Magnetic Iron Oxide (Fe3O4) and Silver (Ag) nano particles with engine oil (EO) as based fluid. A uniform magnetic field perpendicular to the plate is also taken. General solutions of the problems are obtained with the help of Laplace Transform Technique. Influence of related physical parameters on the fluid flow are discussed with the help of graphical display of the solutions. It is also observed that generalized boundary conditions provides more effective and new solutions for the oscillating flow of hybrid nanofluid which produces a better way of understanding of hybrid nanofluid.

Antimicrobial activity of silver nanoparticles synthesized from Wrightia tinctoria fruit extracts

Nanoparticles are synthesized by using various chemical methods in higher yields but they are not very environmentally friendly and have hazardous effects on living cells. This can be attributed to the overuse of hazardous chemicals involved in the process. The green approach of nanoparticle synthesis is widely gaining attention worldwide as it is considered as nontoxic, harmless and ecofriendly. Apart from this they also have multiple applications in various fields of science and technology. Nanoparticles synthesized by using various phytochemicals are also effective against a variety of microbial populations. The objective of this study is to synthesize silver nanoparticles (AgNPs) from the fruit extracts of Wrightia tinctoria and evaluating its antimicrobial capacities against gram-positive and negative bacterial strains. Silver nanoparticles were synthesized using different solvent extracts of Wrightia tinctoria pods. The formation of silver nanoparticles was noted by detecting the change in color of the solution. The presence of nanoparticles was detected by performing UV visible spectroscopy and monitoring the spectrum from 400 nm to 800 nm. A small peak at 425 nm suggested the presence of silver nanoparticles. In a later part of the study, the inhibitory effect of green synthesized silver nanoparticles on the growth of E. coli and S. aureus was monitored. The appearance of a zone of inhibition further confirmed the antimicrobial effect of the synthesized nanoparticles.

The impact of various forms of silver nanoparticles on the rhizosphere of wheat (Triticum aestivum L.) – Shifts in microbiome structure and predicted microbial metabolic functions

The study investigated the effects of different silver nanoparticles (AgNPs) on the soil microbiome and wheat growth. For comparison purposes, a commercial fungicide and silver nitrate (AgNO3) were used. The results revealed three distinct groups of nanoparticles based on their impacts. Small-size AgNPs (10 nm) with a negative charge, as well as fungicide had limited effects on the microbiome, similar to the no-treatment control. Bigger in size (30–60 nm) and a negative charge AgNPs showed the most beneficial effects on soil microbiota shifts. These AgNPs increased the abundance of bacteria with beneficial traits such as nitrogen-fixing, urease, protease, and lignin degradation bacteria. The third type of AgNPs had a positive charge of nanostructure and influenced specific microbial populations, increasing the abundance of anaerobic and autotrophic groups of microorganisms, which could be assessed as a harmful shift for plants growth promotions and was similar to the AgNO3 treatment. Overall, the study emphasized the potential of AgNPs in agriculture not only as biocidal. The conducted study proved that AgNPs with bigger size/negative charge, used in low concentration can have a surprisingly stimulating effect on the positive characteristics of the rhizosphere microbiome. Moreover, the surface charge of AgNPs is a significant factor affecting microbial activity of wheat rhizosphere soil, which in this treatment is significantly similar to the AgNO3 treatment.

Modulation of Staphylococcus aureus Biofilm Formation through Subinhibitory Concentrations of Biogenic Silver Nanoparticles and Simvastatin

Staphylococcus aureus is a causative agent of nosocomial infections and its antibiotic-resistant strains give cause for concern. Solutions are being explored to improve treatment for these infections, including repositioning drugs such as statins and using nanoparticles with antimicrobial properties. This study evaluated the antimicrobial effects of simvastatin (SIM) and biologically synthesized silver nanoparticles (bio-AgNPs) in isolate form and in combination using assays of minimum inhibitory concentration (MIC), an in vitro biofilm model, and the association of antimicrobials against clinical strains of S. aureus. Bio-AgNPs showed a 53.8 ± 1.23 nm mean diameter and standard deviation, a 0.23 polydispersity index, and a −25.66 ± 2.19 mV mean potential and standard deviation. Transmission electron microscopy confirmed the formation of nanoparticles, and the presence of Ag0 and AgCl. S. aureus strains were sensitive to bio-AgNPs and SIM, showing 31.88–187.5 and 74.66–149.32 μM concentrations, respectively. The association assay showed 2.0 fractional inhibitory concentration indices (i.e., indifferent for clinical strains) and 0.32 values for the standard ATCC 29213 strain (synergy). Biofilm inhibition assays with isolated SIM and bio-AgNPs showed decreased biofilm formation 4× to ⅛ MICs concentrations, showing no synergism in association. These findings evince that simvastatin and bio-AgNPs at subinhibitory concentrations can serve as antimicrobial agents against S. aureus biofilm.

Phytochemical Profiling, Green Synthesis, and Bioactivity Evaluation of Silver Nanoparticles (AgNPs) Synthesized from Ipomoea laxiflora Extract

This study focuses on the eco-friendly production of silver nanoparticles using leaf extract from Ipomoea laxiflora and assesses their antioxidant and hemolytic effects. To our knowledge, this is the first report on the synthesis of silver nanoparticles using this species. Green synthesis offers immense potential in both medical and environmental fields, aiming to utilize less hazardous chemicals. Plant-based synthesis, in particular, is considered safe and effective due to the presence of reducing and capping agents within plant extracts. Ipomoea laxiflora H.J. Chowdhery & Debta, belonging to the Convolvulaceae family, is an annual climber native to Tropical Africa and India. It has been traditionally used to treat fever, headaches, and stomach aches. Phytochemical screening revealed the presence of alkaloids, flavonoids, saponins, phenols, tannins, terpenoids, steroids, glycosides, and cardio glycosides. Quantification of phytochemical contents, including total phenolic, flavonoid, and proanthocyanin content, was also performed. FT-IR spectroscopic analysis indicated characteristic peak values of major functional groups such as alkene, alkane, and carbonyl. Silver nanoparticles were synthesized by adding 10 mL of methanolic leaf extract to 90 mL of 1 mM aqueous silver nitrate solution, followed by heating at 80 degrees Celsius for three hours with continuous stirring. The change in color from yellow to dark brown confirmed the formation of silver nanoparticles. The antioxidant activity, determined by DPPH radical scavenging assay, showed 94% scavenging activity for methanolic extract compared to 98% for ascorbic acid. Higher concentrations exhibited increased scavenging activity. Total antioxidant activity ranged from 60% to 89% in hexane and methanol extracts, with methanol showing the highest concentration. Hemolytic activity was observed between concentrations of 10 to 100 µg/ml, with a hemolysis rate of 2.751% at a concentration of 100 µg/mL. The development of green nanoparticles using natural sources like Ipomoea laxiflora holds significant importance for environmental sustainability, health benefits, diverse biomedical applications, resource efficiency, and cost-effectiveness. Embracing such green approaches not only advances nanotechnology but also aligns with broader goals of promoting sustainable development.

Silver nanoparticles (NPAg) using padina australis seaweed

The synthesis of silver nanoparticles (NPAg) using Padina australis seaweed as a bioreductor and AgNO₃ as a precursor through the green synthesis method was successfully achieved. This environmentally friendly approach utilized various concentrations of the seaweed extract and silver nitrate precursor, resulting in the formation of silver nanoparticles at each concentration variation. The stability of these nanoparticles was confirmed by the observable changes in solution color, maximum wavelength, absorbance, and peak length shift. The process exhibited consistent results, with minimal wavelength variation occurring within 1 to 6 hours, particularly at a concentration ratio of 3 mM and 5:10 mL extract to precursor. These findings demonstrate the potential of Padina australis seaweed in the sustainable production of silver nanoparticles, offering a green alternative for nanoparticle synthesis.

Synergistic antibacterial and mosquitocidal effect of Passiflora foetida synthesized silver nanoparticles.

Silver nanoparticles are opted to have various applications in different fields ranging from traditional medicines to culinary items. It is toxic and most effective against bacteria, fungi viruses, parasites, parasite carrying vectors such as mosquitoes and their larvae and other eukaryotic microorganisms at low concentration without any side effects and toxicity to humans. In view of these data, the present research has been investigated by synthesizing silver nanoparticles using 1mM silver nitrate and aqueous extract of Passiflora foetida. The variation of nanoparticles in size and shape concerning the concentration of extract prepared were analysed. The formation of silver nanoparticles was confirmed by colour changing from yellowish green to reddish-brown implicating the surface plasmon resonance. Further, it was concluded by obtaining an absorbance peak at 420 nm using UV-Visible spectrophotometer analysis. FTIR analysis was used to identify the capping ligands, which included alkanes, aromatic groups and nitro compounds. The average grain size of ~12 nm to 14 nm with crystalline phase was revealed by X-ray Diffraction studies. The SEM images depicted the surface morphology with agglomeration; TEM studies showed the shape of nanoparticles as spherical and hexagonal with sizes ranging from 40 nm to 100 nm and EDAX analysis confirmed the presence of elemental silver as the principal constituent. The characterized silver nanoparticles were then tested for synergistic antibacterial effects with tetracycline, and the results show that they are more active against E. coli and S. aureus, but moderately effective against B. cereus and K. pneumoniae . It also had a strong larval and pupal toxic effects on the dengue vector, Aedes aegypti with the highest mortality. As a result, silver nanoparticles could be a viable alternative for a variety of applications.

Biogenic synthesis of silver nanoparticles using Rubus fruticosus extract and their antibacterial efficacy against Erwinia caratovora and Ralstonia solanacearum phytopathogens.

In the current research, we produced green, cost-effective, eco-friendly silver nanoparticles using a single-step approach. Plants are considered highly desirable systems for nanoparticle synthesis because they possess a variety of secondary metabolites with significant reduction potential. In the current research, the dried leaf extract of Rubus fruticosus was utilized as a capping and reducing agent for the fabrication of silver nanoparticles, to prepare reliable biogenic silver nanoparticles and subsequently to investigate their potential against some common phytopathogens. The prepared silver nanoparticles were exploited to quantify the total flavonoid content (TFC), total phenolic content (TPC) and DPPH-based antioxidant activity. Different concentrations of aqueous extracts of plant leaves and silver nitrate (AgNO3) were reacted, and the color change of the reactant mixture confirmed the formation of Rubus fruticosus leaf-mediated silver nanoparticles (RFL-AgNPs). A series of characterization techniques such as UV-vis spectroscopy, transmission electron microscopy, energy dispersive X-ray analysis and X-ray diffraction revealed the successful synthesis of silver nanoparticles. The surface plasmon resonance peak appeared at 449 nm. XRD analysis demonstrated the crystalline nature, EDX confirmed the purity, and TEM demonstrated that the nanoparticles are mostly spherical in form. Furthermore, the biosynthesized nanoparticles were screened for in vitro antibacterial activity, antioxidant activity, and total phenolic and flavonoid content. The nanoparticles were used in different concentrations alone and in combination with plant extracts to inhibit Erwinia caratovora and Ralstonia solanacearum. In high-throughput assays used to inhibit these plant pathogens, the nanoparticles were highly toxic against bacterial pathogens. This study can be exploited for planta assays against phytopathogens utilizing the same formulations for nanoparticle synthesis and to develop potent antibacterial agents to combat plant diseases.

The role of pH-induced tautomerism of polyvinylpyrrolidone on the size, stability, and antioxidant and antibacterial activities of silver nanoparticles synthesized using microwave radiation.

Tautomerism alters the structure and properties of materials, which can be exploited to control their chemical and biological activities. The role of pH-induced tautomerism of polyvinylpyrrolidone (PVP) was determined by measuring the size, stability, and antioxidant and antibacterial properties of microwave synthesized-silver nanoparticles (AgNPs). TEM and XRD analyses confirmed the formation of face-centered cubic silver nanoparticles. PVP stabilized the AgNPs by interaction with the carbonyl or hydroxyl groups depending on the tautomerization under different pH conditions. At pH 4, PVP was stable in the keto tautomer, stabilizing Ag through electron donation of oxygen atoms in the carbonyl group, producing smaller AgNPs with a higher zeta potential. At pH 7 and 9, the enol tautomer PVP stabilized the AgNPs via oxygen atoms in the hydroxyl group, forming large nanoparticles. The keto form of PVP improved the stability and antioxidant and antibacterial properties of AgNPs compared with the enol form. This study also excluded the antioxidant contribution of PVP via hydrogen donation to free radicals. A facile method for controlling the size of AgNPs by adapting the pH-induced tautomerism of PVP that affects their stability and antioxidant and antibacterial activities is thus reported.

Concentration and pH Influence on the Reducing Property of Silk Fibroin from Silk Fibrous Waste in the Green Synthesis of Silver Nanoparticles

The development of methods of green synthesis of metal nanoparticles from the use of biological agents, and microbial or plant extracts, allows the obtainment of biocompatible nanostructures by reducing or eliminating the use of toxic substances. On that basis, this research focused on evaluating the influence of silk fibroin from silk fibrous waste (SFw) on the synthesis of silver nanoparticles (AgNPs), by varying the concentrations of the precursor and reducing agent, as well as the change in the pH value of the reaction. The nanostructures were characterized by UV‐visible spectrophotometry, scanning transmission electron microscopy (STEM) and transmission electron microscopy (TEM), zeta potential, and Fourier transform infrared spectroscopy (FTIR) with an ATR module. The results showed that SFw behaves as a reducing matrix and micellar structure, which favored the formation and obtainment of silver nanoparticles with colloidal stability, particle diameters, and defined morphologies. These aspects were evidenced through the identification of the characteristic surface plasmon resonance of the silver ion, the determination of the particle diameter, the electrokinetic potential, and the identification of the functional groups because of the oxidation of the reducing agent.

Effect of silver nanoparticles in treating and healing of burn wound

The paper investigates the effect of silver nanoparticles preparations on the rate of burn healing and scar quality. Three preparations for burn treatment were considered: one with silver sulfadiazine and two with silver nanoparticles woven into two types of dressing: one, of polyethylene and second, carboxymethyl cellulose. The experiment was performed on pigs, due to anatomical and pathophysiological similarities with human skin. All three silver preparations have antimicrobial properties with a beneficial effect on the healing of burns. Preparations with silver nanoparticles proved to be the most effective, since they encourage very fast burn epithelialization, affect reduction of the level of matrix metalloproteinase-9 in the environment of the burn wound, lead to faster expression of vascular endothetial growth factor ? VEGF, cause less thickening of the epidermis and contractility, and improve tension characteristics of the scar compared to the preparation with silver sulfadiazine. By comparing results of healing parameters and evaluation of the scar achieved with preparations with silver nanoparticles, it was evident that the best overall results of local treatment were achieved with silver nanoparticles in crystalline form. Due to quantum-mechanics, surface and chemical oxidation?reduction (reactive oxygen species) phenomenological characteristics Ag nanoparticles in crystalline form have unique ability to catalyze rate of healing.

Preparation of Allium Cepa Peel Extract-mediated Silver Nanoparticles: A Hair Dye Formulation.

The burgeoning field of nanotechnology has ushered in innovative Novel drug delivery systems (NDDS) that enhance the efficacy, safety, and patient compliance of pharmaceutical treatments. This study explores the synthesis and application of silver nanoparticles (AgNPs) using green chemistry approaches, specifically leveraging plant extracts as reducing agents. AgNPs, known for their unique physical and chemical properties, including antimicrobial capabilities, offer significant potential in modern drug delivery. This study investigates the potential of using Allium cepa peel waste for the green synthesis of silver nanoparticles. This study also revealed the resultant formation of silver nanoparticles through microscopy and UV spectroscopy, which were further analyzed by Scanning Electron Microscopy. This green synthesis method not only aligns with environmentally friendly practices but also provides a cost-effective and scalable approach to nanoparticle production. We formulated a hair dye incorporating these AgNPs and evaluated its physicochemical parameters, demonstrating enhanced performance compared to control formulations without nanoparticles. This work underscores the promise of green-synthesized nanoparticles in developing advanced drug delivery systems, offering insights into future applications in anticancer and antimicrobial treatments. Our findings advocate for the broader adoption of sustainable nanotechnology in pharmaceutical sciences, potentially revolutionizing the treatment landscape with safer and more effective therapeutic options.

Room temperature cured silver nanoparticle embedded hybrid nanocomposite coatings: processing and property evaluation

In situ formation of silver nanoparticles in an inorganic–organic hybrid matrix cured at room temperature (30 ± 5 °C).

Solid polymer electrolyte and antimicrobial performance of Polyvinyl alcohol/Silver nanoparticles composite film

A nanocomposite based on polyvinyl alcohol (PVA) is developed using silver nanoparticles (Ag NPs) prepared by the chemical reduction method. The nanocomposite is analyzed by X-ray diffraction method (XRD) and Fourier transform infrared (FTIR) analyses. XRD analysis confirms the purity of the synthesized silver nanoparticles with the average crystallite size of 15 nm. It also shows the presence of nanoparticles in the nanocomposite films. The interaction of silver nanoparticles with the polymer matrix is demonstrated by the FTIR spectrum. Scanning electron microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDAX) and UV–Visible spectroscopy confirm the formation of silver nanoparticles with spherical morphology and surface Plasmon resonance at 424 nm. Further, nanocomposite as solid polymer electrolyte and antimicrobial properties of the nanocomposite are illustrated. The addition of nanoparticles increases the electrical conductivity (1.7866 × 10-6 Scm−1) of the PVA silver nanocomposite film that is measured from electrochemical impedance spectroscopy through Cole-Cole plots. The PVA/Silver nanoparticles composite films show a high zone of inhibition for both Gram-negative and Gram-positive bacteria than pure PVA films. The electrochemical performance shows the ability to use as a solid polymer electrolyte in electrochemical devices. Polyvinyl alcohol (PVA)/Silver nanoparticles composite films with high anti-bacterial activity can be used for wound dressings and active food packaging.

The Antibacterial Activity of Angelica glauca in form of Silver Nanoparticles

Angelica glauca have been used traditionally as an over the counter herbal preparation, nowadays nanotechnology formulate metal nanoparticles from Angelica glauca in green synthesis method which increase Angelica glauca pharmacology and pharmaceutical application. The aims of present work were to synthesis Angelica glauca silver nanoparticles from its methanolic extract, phytochemicals detection, investigation the morphology and chemical compound characteristic present in Angelica glauca AgNPs by spectroscopic method of FT-IR, and scan electron microscope, and finally in vitro evaluation the antibacterial activity of Angelica glauca in forms of methanolic extract and silver nanoparticles. Extraction by soxhlet was the method used in preparation Angelica glauca methanolic extract, to be use in preparation Angelica glauca silver nanoparticles, 5 phytochemicals were detected, in addition to detection Angelica glauca AgNPs characteristic of active chemical compound and nanoparticles morphology by FT-IR and SEM, in vitro assessment antibacterial activity against Four types of control bacteria. Methanolic extract weight yielded from 250 g of Angelica glauca was 13.3g, in addition to phytochemical detection test was positive for alkaloids, flavonoids, tannins, steroids and coumarins. However, detection of terpenoids, carbohydrate, saponine, quinine, and proteins showed negative result, FT-IR spectroscopy, which showed a sharp band with different wave length, indicating the presence of multi- functional group as aliphatic –CH3, olefinic –C=C-, and carbonyl C=O, particle size detected by SEM )mean ±SD) was 70.9nm±13.60. The antibacterial activity of Angelica glauca AgNPs was higher than methanolic extract. The two formula of Angelica glauca exhibit a varying degree of antibacterial activity, Angelica glauca contain many bioactive phytochemical compounds when reduced to nanoparticles which can be used in curing health related problems and in many pharmaceutical application across the globe.

Phytochemical Screening and Green Synthesis of Antibacterial Silver Nanoparticles of Sapindus mukorossi Fruit Extracts

Background: Plants, herbs, and ethnobotanicals have been utilized for health promotion and disease treatment since the dawn of time and are still widely employed today. The immense demand and potential health advantages of herbal medicines balance out the enormous research demands. There is a need for research on the quality, safety, molecular effects, and therapeutic efficacy of the many common herbs. Aim and Objective: The aim of the study is to prepare Silver Nanoparticles using fruit extract of Sapindus Mukorossi by green synthesis technique, and to develop new derivatives of antibiotic due to high resistance from conventional antibiotics. Method: The Sapindus mukorossi fruit extract AgNPs was prepared by green synthesis technique. Formulation of silver nanoparticles using water/methanol reetha fruit extract was carried out by addition of fruit extract to a reaction mixture containing 1M AgNO3 and 0.625% ammonia solution and left for 48hrs in dark place with regular interval exposing to light. The prepared silver nanoparticles were characterized using SEM, FTIR and XRD studies. Result: The synthesized nanoparticles found to be spherical and crystalline in nature. The FTIR measurements identifies the functional groups attributed for silver ions reduction and AgNPs stabilization. The synthesized yield was 58.34%, 77.46%, 49.67% and 69.32% respectively. The methanol extract shows greater activity than Aqueous extract against E.coli and Streptococcus aureus. Conclusion: The Phyto-based drugs exhibit good medicinal properties with less side-effects as compare to synthetic based drugs. The reetha is known for its many properties such as foaming agent, antibacterial activity etc. The idea was to develop the new antibacterial drugs as the humans getting resistant to the antibacterial drugs. The antibacterial results show that the prepared AgNPs were effective in inhibiting growth of both S. aureus and E. coli bacteria, and hence they could be potential applications in bio-related field.

Formation of antimicrobial silver nanoparticles on silica

Синтезирован новый антимикробный материал на основе кремнезема с иммобилизованными на поверхности наночастицами серебра SiO2/Ag0 различного размера. Нанесение катионов Ag+ из раствора на поверхность носителя SiO2 и встраивание восстановленных наночастиц серебра Ag0 в структуру кремнезема Силохром С-80 приводит к равномерному распределению наночастиц вокруг мезопор, а также способствует появлению антибактериальных свойств. Морфология, структура и кислотно-основные свойства поверхности нанокомпозита определяют активность сорбционно-антимикробных материалов. Положительный заряд Ag+ в составе полученного нанокомпозита способствует взаимодействию с отрицательно заряженной оболочкой бактерий, что является дополнительным эффектом повышения активности наноструктур. Установлена преобладающая роль кислотно-основных центров SiO2 в антибактериальной активности наноструктур SiO2/Ag0 и определены условия ее путем изменения размера и локализации наночастиц Ag0 в результате термической обработки при 500 °Ϲ, которая приводит к снижению минимальной ингибирующей концентрации в 6-7 раз. Полученные результаты позволяют оценить характер влияния как наночастиц серебра, так и поверхности кремнезема на антибактериальную способность наноструктур. Величина антибактериальной активности по отношению к E.coli и S.aureus зависит от размера наночастиц, которая определяется термической обработкой после нанесения на поверхности

The Effect of Silver Nanoparticles/Titanium Dioxide in Poly(acrylic acid-co-acrylamide)-Modified, Deproteinized, Natural Rubber Composites on Dye Removal.

This work aims to enhance the dye-removal performance of prepared poly(acrylic acid-co-acrylamide)-modified, deproteinized, natural rubber ((PAA-co-PAM)-DPNR) through incorporation with silver nanoparticles/titanium dioxide. The (PAA-co-PAM)-DPNR was prepared by emulsion-graft copolymerization with a grafting efficiency of 10.20 ± 2.33 to 54.26 ± 1.55%. The composites based on (PAA-co-PAM)-DPNR comprising silver nanoparticles and titanium dioxide ((PAA-co-PAM)-DPNR/Ag-TiO2) were then prepared by latex compounding using the fixed concentration of AgNO3 (0.5 phr) and varying concentrations of TiO2 at 1.0, 2.5, and 5.0 phr. The formation of silver nanoparticles was obtained by heat and applied pressure. The composites had a porous morphology as they allowed water to diffuse in their structure, allowing the high specific area to interact with dye molecules. The incorporation of silver nanoparticles/titanium dioxide improved the compressive modulus from 1.015 ± 0.062 to 2.283 ± 0.043 KPa. The (PAA-co-PAM)-DPNR/Ag-TiO2 composite with 5.0 phr of TiO2 had a maximum adsorption capacity of 206.42 mg/g, which increased by 2.02-fold compared to (PAA-co-PAM)-DPNR. The behavior of dye removal was assessed with the pseudo-second-order kinetic model and Langmuir isotherm adsorption model. These composites can maintain their removal efficiency above 90% for up to five cycles. Thus, these composites could have the potential for dye-removal applications.

Ag Nps@PEDOT Nanocomposite Electrosynthesis at a Polarised Liquid|Liquid Interface

One of Material Science's main challenges is constantly searching for new versatile materials. In this sense, nanocomposites have emerged as an alternative to new substrates due to their unique properties. These hybrid systems are made up of organic polymers with inorganic components. This ideal "tandem" is made up of organic polymers (for example, poly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole (PPy) and polyaniline (PANI)) with conductive characteristics because of their highly p-conjugated polymeric chains, unique properties, reversible doping/de-doping processes, and controllable chemical/electrochemical properties. Inorganic compounds, such as metallic nanoparticles (NPs), in the organic matrix provide a high surface area and conductivity, acting as protuberances and highly conductive fillers to form a class of material with multidisciplinary applications [1].There are several methods to generate organic polymers; the electrochemical process is one of the most used due to its versatility and simplicity. This method implies the electrodeposition of the organic polymer on an electrode surface, eliminating the possibility of obtaining a polymeric material separated from the electrode surface and limiting the areas of applicability (polymer firmly attached to the electrode surface). In this sense, the use of a polarised immiscible liquid|liquid (L|L) interfaces is demonstrated as a novel approach for the electrosynthesis of surfactant-free organic thin films, allowing complete control over the thin film morphology [2].In this work, we present the electrosynthesis of silver nanoparticles@PEDOT nanocomposites based on EDOT polymerization (PEDOT) and the formation of silver nanoparticles by electrochemical polymerisation at a polarised L|L interface. In thermodynamic terms, the oxidant potential of silver ions is insufficient to oxidise 3,4-ethylenedioxythiophene and generate PEDOT. However, under specific conditions (detailed in this presentation), silver ions are reduced while EDOT monomers are oxidised to PEDOT. A deep knowledge of biphasic electropolymerisation coupled with silver nanoparticle formation will help advance the search for new materials for a broad spectrum of applications (antibacterial, electrocatalysis, SERS substrates, biocompatibility substrates, etc.).

FILM MATERIALS BASED ON POLYVINYL ALCOHOL, FILLED WITH SILVER NANOPARTICLES

In the present work polymeric composite films materials based on polyvinyl alcohol (PVA), glycerol and silver nitrate the conducted composites with high mechanical characteristics were created. In the process of composites drying, glycerol acts as a reducing agent and the formation of silver nanoparticles occurs, moreover the reducing take places at room temperature. The AgNO3 content is varied from 0.01 to 30 wt.%. Taking into account the physical-mechanical and conducting properties of composites, it is established that the optimum content of glycerol in the final material is equal to 30 wt%. The formation of metallic silver was confirmed by an appearance of a surface plasmon resonance band at 420-430 nm in UV spectra and the appearance of two diffraction peaks at 38.17° and 44.15° in X-ray diffraction pattern as well, corresponding to the crystallographic planes (111) and (200) of a face centered cubic lattice of Ag0. Dielectric spectroscopy data show that the increasing of glycerol content up to 30-40 wt.% leads to enhance the conductivity by three orders in comparison with the initial PVA. An increase in the silver content resulted in further rise of the conductivity, reaching value of 5.72 10-6 S/cm at 15 wt.% of silver concentration, at room temperature (20 °C). At 100-120 °С, the conductivity was the highest for the composite with 25 wt.% of AgNO3 - 3.67-3.84 10-4 S/cm. The resulting samples had high physical and mechanical properties: relative elongation of about 400%, tensile strength of 32–36 MPa. Studies of the dynamic light scattering of films solution with Ag NPs showed that the smallest size was for the sample with 0.5 wt.% - 6.3 nm.