- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Multifunctional Flax Fibres Based on the Combined Effect of Silver and Zinc Oxide (Ag/ZnO) Nanostructures
摘要： Cellulosic fibre-based smart materials exhibiting multiple capabilities are getting tremendous attention due to their wide application areas. In this work, multifunctional flax fabrics with piezoresistive response were developed through the combined functionalization with silver (Ag) and zinc oxide (ZnO) nanoparticles (NPs). Biodegradable polyethylene glycol (PEG) was used to produce AgNPs, whereas ZnONPs were synthetized via a simple and low-cost method. Flax fabrics with and without NPs were characterized by Ground State Diffuse Reflectance (GSDR), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), and Thermogravimetric analysis (TGA). After creating a conductive surface by flax functionalization with AgNPs, ZnONPs were synthetized onto these fabrics. The developed fibrous systems exhibited piezoresistive response and the sensor sensitivity increased with the use of higher ZnO precursor concentrations (0.4 M). Functionalized fabrics exhibited excellent antibacterial activity against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria, higher hydrophobicity (WCA changed from 00 to >1000), UV radiation resistance, and wash durability. Overall, this work provides new insights regarding the bifunctionalization of flax fabrics with Ag/ZnO nanostructures and brings new findings about the combined effect of both NPs for the development of piezoresistive textile sensors with multifunctional properties.
关键词： piezoresistive response,smart and multifunctional materials,cellulosic fibres,silver and zinc oxide nanoparticles,antibacterial effect,hydrophobicity
更新于2025-09-04 15:30:14
-
Preparation of ZnO Nanoparticles Under Ultrasonic Irradiation and Photocatalytic Performance of ZnO Nanoparticles Multilayer Films
摘要： Zinc oxide nanoparticles were synthesized by the reaction of an aqueous-alcoholic solution containing zinc nitrate hexahydrate and sodium hydroxide under ultrasonic irradiation at room temperature. The crystallinity, morphology and optical property of ZnO nanoparticles were examined by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and UV-visible spectrophotometer. Zinc oxide nanoparticles multilayer films were prepared dipping glass slide, which had been cleaned with a piranha solution, into a ZnO solution by ultrasonic irradiation. The ZnO nanoparticles multilayer films were evaluated as a photocatalyst in the photocatalytic degradation of organic dyes, such as methylene blue, methyl orange and rhodamine B, under ultraviolet light at 254 nm.
关键词： Multilayer films,Photocatalytic activity,Zinc oxide nanoparticles,Organic dyes,UV-visible spectrophotometer
更新于2025-09-04 15:30:14
-
Metastable crystalline phase in two-dimensional metallic oxide nanoplates
摘要： Structural phase transition in crystals induced by high-pressure or high-temperature conditions may result in the development of unusual physical and chemical properties; these properties are often difficult to stabilize under ambient conditions. Here we adopted a simple method in which ultrathin cerium oxide nanoplates (< 1.4 nm) were synthesized to increase the surface atomic content, allowing transformation from a face-centered cubic (fcc) phase to a body-centered tetragonal (bct) phase. Three types of cerium oxide nanoparticles of different thicknesses, i.e., 1.2-nm ultrathin nanoplates, 2.2-nm nanoplates, and 5.4-nm nanocubes, were examined using transmission electron microscopy and X-ray diffraction. The metastable bct phase was observed only in ultrathin nanoplates. Thermodynamic energy analysis confirmed that the surface energy of the ultrathin nanoplates is the cause of the remarkable stabilization of the metastable bct phase. The mechanism of surface energy regulation can be expanded to other metallic oxides, thus providing a new means for manipulating and stabilizing novel materials under ambient conditions that otherwise would not be recovered.
关键词： metastable phase,thickness,surface unsaturated coordination ratio,Ultrathin nanoplates,metallic oxide nanoparticles
更新于2025-09-04 15:30:14
-
Surfactant Free Hydrothermal Synthesis of Zn <sub/>2</sub> SnO <sub/>4</sub> Nanoparticles and Their Functional Properties
摘要： A simple, low temperature, cost effective, surfactant free and scalable synthesis of technologically important Zn2SnO4 (ZTO) nanoparticles with controllable size and shape has been developed. X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) of the synthesized ZTO nanoparticles revealed the formation of highly pure crystalline ZTO phase with the spinel-like structure. The Raman spectrum of the sample was dominated by the A1g vibration mode of pure ZTO phase. From UV–Vis absorption measurements, a band gap (Eg) of 3.78 eV was determined. The photocatalytic activity of the ZTO nanoparticles was evaluated for the photodegradation of methylene blue (MB) under UV-Vis light irradiation. The ZTO-assisted photocatalytic degradation of MB is complete in 25 minutes indicating good photocatalytic activity of ZTO. Mass spectrometric (MS) analysis of degradation intermediates isolated at regular time intervals reveals the presence of azure A, azure B and thionin which are demethylated products of the MB, indicating that the degradation is initiated by demethylation of the molecule.
关键词： Nanoparticles,Photocatalysis,Zn2SnO4,Transmission electron microscopy,Hydrothermal Synthesis
更新于2025-09-04 15:30:14
-
Synthesis of silver nanoparticles from bottom up approach on borophosphate glass and their applications as SERS, antibacterial and glass-based catalyst
摘要： In this paper, we report a facile, low cost synthesis and characterization of silver nanoparticles (AgNPs) on borophosphate glass by a two-step process involving a melting quenching technique and a post-annealing method. The structural, optical properties and several applications of silver-doped borophosphate glasses as a function of Al2O3 concentration are reported here. Micro Raman and infrared spectroscopies revealed that the addition of aluminium ions leads to depolymerization and the formation of phosphate-aluminium structures. Moreover, the addition of Al2O3 increases the glass transition temperature, improve the chemical stability, and the AgNPs remain ?rmly grafted (i.e., not released) when the glass surface is exposed to water. The presence of silver ions and metallic silver on glass surface was con?rmed by the X-ray photoelectron spectroscopy (XPS) and X-ray powder di?raction (XRD), respectively. The fabricated AgNPs have many advantages, such as low growth temperature and good uniform nanoparticle clusters over large areas, size-controlled, and easy to fabricate. Finally, the silver-doped glasses have proved to be an ideal substrate for highly e?cient SERS applications, antibacterial materials and great potential in catalysts.
关键词： Antimicrobial glass,Glass catalyst,Borophosphate glasses,SERS substrates,Silver nanoparticles
更新于2025-09-04 15:30:14
-
Integrating an ex-vivo skin biointerface with electrochemical DNA biosensor for direct measurement of the protective effect of UV blocking agents
摘要： Skin cancer is the most frequent kind of cancer in white people in many parts of the world. UV-induced DNA damage and genetic mutation can subsequently lead to skin cancer. Therefore development of new biosensing strategies for detection of UV-induced DNA damage is of great importance. Here we demonstrate a novel combination of an ex-vivo skin biointerface and an electrochemical DNA sensor for the direct detection of UV induced DNA damage and investigation the protective effect of various UV blockers (Zinc-oxide (ZnO), titanium-dioxide (TiO2) nanoparticles (NPs) and sunscreens) against DNA damage. A diazonium modified screen-printed carbon electrode immobilized with a DNA sequence related to the p53 tumour suppressor gene, the most commonly affected gene in human UV-induced skin cancer, was applied as an electrochemical DNA sensor. Electrochemical impedance spectroscopy (EIS) was employed for the detection of DNA damage induced by UV-A radiation by following the changes in charge transfer resistance (Rct). The protective effects of UV blockers applied onto a pig skin surface (a suitable model representing human skin) were successfully detected by the DNA sensor. We observed that the naked skin has little UV protection showing an 18.2% decreases in ?R/R values compared to the control, while applying both NPs and NP-formulated sunscreens could significantly reduce DNA damage, resulting in a decrease in ?R/R values of 67.1% (ZnO NPs), 77.2% (TiO2 NPs), 77.1% (sunscreen 1) and 92.4% (sunscreen 2), respectively. Moreover, doping moisturising cream with NPs could provide a similar DNA protective effect. This new method is a biologically relevant alternative to animal testing and offers advantages such as fast, easy and inexpensive processing, in addition to its miniaturised dimension, and could be used for a range of applications in other sources of DNA damage and the protective effect of different UV blocking agents and other topical formulations.
关键词： sunscreens,electrochemical DNA biosensor,skin biointerface,DNA damage,nanoparticles
更新于2025-09-04 15:30:14
-
Controllable synthesis of transparent dispersions of monodisperse anatase-TiO2 nanoparticles and nanorods
摘要： Controllable synthesis of monodisperse nanocrystals is still a great challenge. In this study, the control strategy of alcohol medium was developed to conveniently synthesize monodisperse anatase-TiO2 nanocrystals with controllable size and shape by sol-gel method combined with solvothermal treatment. The effects of the amount of stearic acid and water, and molecular structure of alcohol on the size, the shape and the dispersity of TiO2 nanocrystals were explored. The optimum synthesis conditions were achieved. Monodisperse TiO2 nanoparticles and nanorods were obtained by using linear and branched alcohols, respectively. The size of nanoparticles decreased from 12 to 5 nm with increasing carbon number of linear alcohol. The aspect ratio of nanorods was adjusted from 1 to 5 by selecting alcohols with different locations of branched methyl group. The as-prepared monodisperse TiO2 nanocrystals could be readily dispersed in some commonly-used solvents to form transparent nanodispersions. Furthermore, a possible formation mechanism was also investigated.
关键词： Monodisperse TiO2 nanocrystals,transparent dispersion,nanoparticles,nanorods,tunable preparation
更新于2025-09-04 15:30:14
-
Oxygen and cerium defects mediated changes in structural, optical and photoluminescence properties of Ni substituted CeO2
摘要： Local and long-range structural properties, of sol-gel synthesized, Ce1-xNixO2 (0 ≤ x ≤ 0.1) nanopowders have been investigated. Substitution of Ce4+ by comparably smaller Ni2+/Ni3+ ions leads to decrement in lattice parameters. UV-visible spectra reveal decrease of bandgap with increase of disorder upon increasing Ni substitution. The photoluminescence (PL) spectra reveal five major peaks attributed to various defect states. Ni substitution results in the creation of oxygen vacancies (VO) which further leads to conversion of considerable amount of Ce4+ ions to larger size Ce3+. These changes notably, modify the structure of the host lattice. The defects created along with the structural modifications bring, changes in the PL emission. The disorder in the lattice results in increase of non-radiative decay which reduces the PL emission. An increasing VO and Ce3+ concentration at the surface acts as emission quenching centers. Lattice disorder and VO quantities were estimated using X-ray absorption (XAS), UV-vis and Raman spectroscopy.
关键词： Nanoparticles,Urbach energy,Cerium oxide,Strain,Bandgap
更新于2025-09-04 15:30:14
-
Generic Assay of Sulfur-Containing Compounds Based on Kinetics Inhibition of Gold Nanoparticle Photochemical Growth
摘要： This work describes a new, equipment-free, generic method for the determination of sulfur-containing compounds that is based on their ability to slow down the photoreduction kinetics of gold ions to gold nanoparticles. The method involves tracking the time required for a red coloration to appear in the tested sample, indicative of the formation of gold nanoparticles, and compare the measured time relative to a control sample in the absence of the target analyte. The method is applicable with minimal and simple steps requiring only two solutions (i.e., a bu?er and a gold solution), a source of light (UV or visible), and a timer. The method responds to a large variety of sulfur-containing compounds including thiols, thioesters, disul?des, thiophosphates, metal?sulfur bonds, and inorganic sulfur and was therefore such as applied to the determination of a variety of compounds dithiocarbamate and organophosphorous pesticides, biothiols, pharmaceutically active compounds, and sul?des in di?erent samples such as natural waters and wastewater, biological ?uids, and prescription drugs. The analytical ?gures of merit of the method include satisfactory sensitivity (quantitation limits at the low μM levels), good recoveries (from 93 to 109%), and satisfactory reproducibility (from 4.8 to 9.8%). The method is easily adoptable to both laboratory settings and nonlaboratory conditions for quantitative and semiquantitative analysis, respectively, is user-friendly even for the minimally trained user, and can be performed with limited resources at low cost.
关键词： equipment-free method,sulfur-containing compounds,time-based assay,gold nanoparticles,photochemical reduction
更新于2025-09-04 15:30:14
-
Luminescent silica based nanostructures from <i>in vivo</i> Iridium-doped diatoms microalgae.
摘要： A novel biotechnological approach to the preparation of Ir-doped luminescent silica based nanostructures is proposed availing of diatoms microalgae which generate highly nanostructured biosilica shells (frustules) by in vivo biomineralization of orthosilicic acid. After the in vivo incorporation of a phosphorescent organometallic complex (Ir-1) in Thalassiosira weissflogii diatom frustules (DFs), bulk functionalized phosphorescent silica based nanostructures are obtained by isolation and proper ultrafine processing of Ir-1 doped DFs. High-resolution characterization reveals the presence of phosphorescent hybrid organic/inorganic clusters (HCs) composed of biogenic silica NPs intimately trapped within the diatom organic residual matter. The bio-factory strategy investigated herein can be a sustainable, cost-effective and scalable route to transition metal doped silica nanomaterials, and can pave the way to a great variety of heavy-metal and rare-earth metal doped silica nanostructures, whose applications range from photonics to imaging, sensing and biomedicine.
关键词： micro-bioreactors,diatoms microalgae,iridium,extraction method,nanoparticles,nanostructures,Biosilica,phosphorescence
更新于2025-09-04 15:30:14