scholarly journals RE-Based Inorganic-Crystal Nanofibers Produced by Electrospinning for Photonic Applications

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2679
Author(s):  
Alessandra Toncelli
Keyword(s):  
Rare Earth ◽  
Near Infrared ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Rare Earth Ions ◽  
Polymer Materials ◽  
Electrospinning Technique ◽  
Rare Earth Doped

Electrospinning is an effective and inexpensive technique to grow polymer materials in nanofiber shape with exceptionally high surface-area-to-volume ratio. Although it has been known for about a century, it has gained much interest in the new millennium thanks to its low cost and versatility, which has permitted to obtain a large variety of multifunctional compositions with a rich collection of new possible applications. Rare-earth doped materials possess many remarkable features that have been exploited, for example, for diode pumped bulk solid-state lasers in the visible and near infrared regions, or for biomedical applications when grown in nanometric form. In the last few decades, electrospinning preparation of rare-earth-doped crystal nanofibers has been developed and many different materials have been successfully grown. Crystal host, crystal quality and nanosized shape can deeply influence the optical properties of embedded rare earth ions; therefore, a large number of papers has recently been devoted to the growth and characterization of rare earth doped nanofibers with the electrospinning technique and an up-to-date review of this rapidly developing topic is missing; This review paper is devoted to the presentation of the main results obtained in this field up to now with particular insight into the optical characterization of the various materials grown with this technique.

scholarly journals Dipsticks with Reflectometric Readout of an NIR Dye for Determination of Biogenic Amines

Chemosensors ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 99
Author(s):  
Sarah N. Mobarez ◽  
Nongnoot Wongkaew ◽  
Marcel Simsek ◽  
Antje J. Baeumner ◽  
Axel Duerkop
Keyword(s):  
Biogenic Amines ◽  
Indium Tin Oxide ◽  
Near Infrared ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Sample Pretreatment ◽  
Primary Amines ◽  
Nir Dye

Electrospun nanofibers (ENFs) are remarkable analytical tools for quantitative analysis since they are inexpensive, easily produced in uniform homogenous mats, and provide a high surface area-to-volume ratio. Taking advantage of these characteristics, a near-infrared (NIR)-dye was doped as chemosensor into ENFs of about 500 nm in diameter electrospun into 50 µm thick mats on indium tin oxide (ITO) supports. The mats were made of cellulose acetate (CA) and used as a sensor layer on optical dipsticks for the determination of biogenic amines (BAs) in food. The ENFs contained the chromogenic amine-reactive chameleon dye S0378 which is green and turns blue upon formation of a dye-BA conjugate. This SN1-reaction of the S0378 dye with various BAs was monitored by reflectance measurements at 635 nm where the intrinsic absorption of biological material is low. The difference of the reflectance before and after the reaction is proportional to BA levels from 0.04–1 mM. The LODs are in the range from 0.03–0.09 mM, concentrations that can induce food poisoning but are not recognized by the human nose. The calibration plots of histamine, putrescine, spermidine, and tyramine are very similar and suggesting the use of the dipsticks to monitor the total sample BA content. Furthermore, the dipsticks are selective to primary amines (both mono- and diamines) and show low interference towards most nucleophiles. A minute interference of proteins in real samples can be overcome by appropriate sample pretreatment. Hence, the ageing of seafood samples could be monitored via their total BA content which rose up to 21.7 ± 3.2 µmol/g over six days of storage. This demonstrates that optically doped NFs represent viable sensor and transducer materials for food analysis with dipsticks.

Fabrication Process Development and Characterization of Polymethylhydrosiloxane (PMHS) for Surface-Modified Microfluidic Chips

2007 ◽  
Author(s):  
Mukund Vijay ◽  
Ehson Ghandehari ◽  
Michel Goedert ◽  
Sang-Joon J. Lee
Keyword(s):  
Laser Ablation ◽  
Soft Lithography ◽  
Process Development ◽  
High Surface ◽  
Volume Ratio ◽  
Fused Silica ◽  
Polymer Materials ◽  
Microfluidic Chips ◽  
Separation Processes

Microfluidic chips made of polymer materials such as polydimethylsiloxane (PDMS), polyimide, and cyclic olefin co-polymer have cost and manufacturing advantages over materials such as fused silica and borosilicate glass. While these materials have been extensively investigated, polymethylhydrosiloxane (PMHS) is an alternative that has a unique combination of properties in terms of UV transparency and potential for chemical surface modification. The present study investigates process development and characterization of PMHS as a new candidate material for microfluidic chip applications, in particular separation processes that would benefit from the ability to custom-engineer its surface conditions. This paper compares different approaches for fabricating microchannel features as well as options for enhancing the surface area of the channel walls. The fabrication methods include replication by casting over patterned molds, soft lithography casting, and material removal by laser ablation. Casting into solid form is achieved in 48-hours at 110 °C. Laser ablation is studied with energy dose varying from 2 mJ to 160 mJ per millimeter scanned, with channels approximately 100 microns wide occurring at 0.2 mJ/mm. Mechanical characterization is applied to quantify the hardness of cast PMHS, because fine-resolution features are limited by mold removal. PMHS samples have been measured to have a Shore A hardness of 46.2, similar to PDMS that is well-established in polymer microfluidic devices. Surface enhancement techniques including laser and plasma treatment are investigated for the prospective benefit of separation processes that require high surface-to-volume ratio. Spectrophotometry shows that PMHS exhibits transmittance even below 250 nm, which is favorable for sample analysis by UV absorption methods.

scholarly journals Morphological evolution of Pt-modified nanoporous gold after thermal coarsening in reductive and oxidative environments

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
A. A. El-Zoka ◽  
B. Langelier ◽  
G. A. Botton ◽  
R. C. Newman
Keyword(s):  
Surface Area ◽  
Morphological Evolution ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Atom Probe ◽  
Nanoporous Gold ◽  
Atomic Scale ◽  
Thermal Coarsening

AbstractNanoporous gold made by dealloying AgAuPt (NPG-Pt) has been shown to exhibit several interesting catalytic properties, tied to its exceptionally high surface area; however, structural degradation may occur owing to thermal coarsening. To understand the effect of atmosphere chemistry on thermal coarsening and degradation, and means of limiting it, this study focuses on the high-resolution characterization of NPG-Pt layers coarsened in reductive Ar-H2 atmosphere, and in oxidative air. Atom probe tomography (APT) analysis is performed on NPG-Pt, coarsened separately in either Ar-H2 or air, to characterize the atomic-scale chemical changes in the nanoligaments and to develop a mechanistic view of the inherent processes. A tendency of Ag to segregate to the surface during coarsening is found to lead to complete elimination of the nanoligament core-shell structures in both cases. Large Pt segregates form during coarsening in Ar-H2, but under the surface of the ligaments, having relatively little effect on the coarsening rate. The oxygen-induced segregation of Pt was observed to cause the inhibition of thermal coarsening after minor loss in surface area-to-volume ratio. Findings in this paper help in understanding further the thermal coarsening of heterogeneous nanomaterials made by dealloying, and the pertinent factors that come into play in different chemical environments.

Graphene Based Nafion® Nanocomposite Membranes for Proton Exchange Membrane Fuel Cells

2011 ◽  
Author(s):  
Vinay K. Adigoppula ◽  
Waseem Khan ◽  
Rajib Anwar ◽  
Avni A. Argun ◽  
R. Asmatulu
Keyword(s):  
Proton Exchange Membrane ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Thermal Characterization ◽  
Proton Exchange Membranes ◽  
Proton Exchange ◽  
Nanocomposite Membranes ◽  
Exchange Membrane

Nanocomposite proton-exchange membranes are fabricated by loading graphene nanoflakes into perfluoro sulfonic acid polymer (Nafion) solutions at controlled amounts (1–4 wt%) followed by electrical and thermal characterization of the resulting membranes. Electronic and ionic conductivity values of the nanocomposites, as well as their dielectric and thermal properties improve at increased graphene loadings. Owing to graphene’s exceptionally high surface area to volume ratio and excellent physical properties, these nanocomposite are promising candidates for proton-exchange membrane fuel cell applications.

DEVELOPMENT OF ELECTROSPUN POLY(VINYLPYRROLIDONE) (PVP) NANOFIBER MATS LOADED BY CALENDULA OFFICINALIS EXTRACT AND COENZYME Q10

2021 ◽  
Author(s):  
Sanja Rackov ◽  
◽  
Aleksandra Nešić ◽  
Milan Vraneš ◽  
Branka Pilić
Keyword(s):  
Coenzyme Q10 ◽  
High Surface ◽  
High Surface Area ◽  
Three Dimensional ◽  
Volume Ratio ◽  
Calendula Officinalis ◽  
Sem Images ◽  
Electrospinning Technique ◽  
Polymer Carrier ◽  
Anti Inflammatory

Electrospun systems can be applied to various areas, particularly in biomedicine for skin treatment. The fabricated nanofibers represent an interconnected three-dimensional network with a high surface area to volume ratio providing structural and morphological similarities with the extracellular matrix. Hence, facilitate the removal of exudates, promote gaseous exchange, conform to the contour of the treated area and in the case of drug-loaded nanofibers resulting in improved bioavailability. Polyvinylpyrrolidone was selected as a polymer carrier due to its biocompatible, hydrophilic nature with good chemical and mechanical properties, approved by the U.S. FDA (Food and Drug Administration) as a safe polymer for biomedical and food applications. Calendula officinalis or Marigold extract is one of the oldest medical plants with numerous proven pharmacological effects including anti-inflammatory, antibacterial/antifungal and wound healing activity related to the components of the flowers such as sesquiterpenes, saponins, triterpenes, flavonoids. Coenzyme Q10 (CoQ10, Ubiquinone) is a naturally occurring oil-soluble antioxidant and anti-inflammatory agent that supports collagen production, mostly popularized as an anti-aging ingredient in skincare products for topical use. Novel Marigold extract and CoQ10–loaded polyvinylpyrrolidone nanofibers intended for skin treatment and wound therapy were developed using the electrospinning technique. The presence of functional groups on the nanofibrous surfaces was confirmed by FTIR analysis, the SEM images show the average size of the obtained nanomats and the thermal properties were investigated via DSC analysis.

Effect of Process Parameters on Continuous Nanofiber Yarn Using Two Oppositely Charged Spinnerets

2013 ◽  
Vol 821-822 ◽  
pp. 32-35
Author(s):  
Xiao E Wang ◽  
Wei Jie Gao ◽  
Kun Wang ◽  
Yong Liu ◽  
Jie Fan
Keyword(s):  
Process Parameters ◽  
Applied Voltage ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Electrospinning Technique ◽  
Nanofiber Yarn ◽  
Potential Applications ◽  
Good Potential ◽  
Oppositely Charged

Nanofiber nonwoven has been used in many fields due to the high surface area to volume ratio of the nanofibers and other extremely excellent properties. Nanofiber yarn, which is composed of long nanofiber with some twists for expanding nanofibers application, has been a challenging. A continuous nanofiber yarn was fabricated by a electrospinning technique with two oppositely charged spinnerets system in this work. The effect of process parameters such as applied voltage, the distance and the angle between the two spinnerets were examined in detail. The optimum parameters obtained included that the applied voltage was ±16kV, the distance and the angle between the two spinnerets were 8cm and 120o respectively. The nanofiber yarn has good potential applications in textile, medical, and biology.

scholarly journals NANOFIBRAS ELETROFIADAS E SUAS APLICAÇÕES: AVANÇOS NA ÚLTIMA DÉCADA

Química Nova ◽  
2021 ◽  
Author(s):  
Luiza Mercante ◽  
Rafaela Andre ◽  
Juliana Macedo ◽  
Adriana Pavinatto ◽  
Daniel Correa
Keyword(s):  
Mechanical Performance ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Electrospun Nanofibers ◽  
Electrospinning Technique ◽  
Structures And Properties ◽  
Wide Range ◽  
Simple Processing

ELECTROSPUN NANOFIBERS AND THEIR APPLICATIONS: ADVANCES IN THE LAST DECADE. In recent years there has been an increasing interest in the development of nanomaterials with improved properties compared to their counterparts at the micro- and macroscopic scale. In this context, nanofibers obtained by electrospinning technique are highly attractive due to the unique combination of high surface area/volume ratio, porosity, flexibility, mechanical performance, simple processing and relatively low cost. In addition, the possibility to buildup nanofibers with different compositions, structures and properties allows the design of nanostructures for a wide range of applications. In this review, we will discuss the advances of the last decade in the use of the electrospinning to obtain nanofibers with different compositions and morphologies for varied applications. Specifically, we are interested in providing an overview of the state of the art in relation to the application of nanofibers in different areas, including healthcare, environment, sensing and energy. Finally, we will discuss the real perspective in terms of industrial application and future trends that have been pursued to improve the performance of electrospun nanofibers. This review will help researchers to understand the evolution and challenges of the area and will also stimulate even more interest in the development of new devices based on electrospun nanofibers

scholarly journals Synthesis and Characterization of Doped and Undoped ZnO Nanostructures

2006 ◽  
Vol 12 (4) ◽  
pp. 327-330 ◽  
Author(s):  
Katie E. McBean ◽  
Matthew R. Phillips ◽  
Ewa M. Goldys
Keyword(s):  
Rare Earth ◽  
Earth Metal ◽  
Rare Earth Ions ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Ethanolic Solution ◽  
Edge Emission ◽  
Rare Earth Doped ◽  
The Rare Earth

Zinc oxide (ZnO) nanoparticles have been produced using precipitation methods from ethanolic solution. Rare-earth metal doping was performed, and the effect of lithium codoping on the luminescence properties of the rare-earth doped products was assessed. The resulting particles were characterized using cathodoluminescence and scanning electron microscopy. It was found that lithium significantly enhanced the cathodoluminescence signal from the rare-earth ions, which has been attributed to the increased integration of the rare-earth ions into the ZnO structure. The nanophase ZnO products were also annealed in argon, hydrogen, and oxygen, with hydrogen being the most successful for removing the broad defect emission present in as-grown samples and enhancing the ZnO near band edge emission.

scholarly journals Electrospun Nanofibers for Sensing and Biosensing Applications—A Review

2021 ◽  
Vol 22 (12) ◽  
pp. 6357
Author(s):  
Kinga Halicka ◽  
Joanna Cabaj
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Toxic Metal ◽  
Volume Ratio ◽  
Electrospun Nanofibers ◽  
Clinical Diagnostics ◽  
Loading Capacity ◽  
Electrospun Nanofiber ◽  
Sensing Platforms ◽  
Different Types

Sensors and biosensors have found applications in many areas, e.g., in medicine and clinical diagnostics, or in environmental monitoring. To expand this field, nanotechnology has been employed in the construction of sensing platforms. Because of their properties, such as high surface area to volume ratio, nanofibers (NFs) have been studied and used to develop sensors with higher loading capacity, better sensitivity, and faster response time. They also allow to miniaturize designed platforms. One of the most commonly used techniques of the fabrication of NFs is electrospinning. Electrospun NFs can be used in different types of sensors and biosensors. This review presents recent studies concerning electrospun nanofiber-based electrochemical and optical sensing platforms for the detection of various medically and environmentally relevant compounds, including glucose, drugs, microorganisms, and toxic metal ions.

scholarly journals NIR-responsive MXene nanobelts for wound healing

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Lin Jin ◽  
Xiaoqing Guo ◽  
Di Gao ◽  
Cui Wu ◽  
Bin Hu ◽  
...  
Keyword(s):  
Wound Healing ◽  
Vitamin E ◽  
Surface Area ◽  
Near Infrared ◽  
Coating Layer ◽  
High Surface ◽  
High Surface Area ◽  
High Mass ◽  
Polymeric Coating ◽  
Mass Loading

AbstractEffectively achieving wound healing is a great challenge. Herein, we facilely prepared temperature-responsive MXene nanobelt fibers (T-RMFs) carrying vitamin E with a controllable release ability for wound healing. These T-RMFs were composed of MXene nanosheets spread along polyacrylonitrile and polyvinylpyrrolidone composite nanobelts together with a thermosensitive PAAV- coating layer. The high mass loading and high surface area of the MXene nanosheets endow the T-RMFs with excellent photothermal properties. The temperature could be easily controlled by near-infrared (NIR) irradiation exposure, and then the thermoresponsive polymeric coating layer relaxed the interface to dissolve vitamin E and promote vitamin E release. The T-RMFs demonstrated excellent biocompatibility and wound-healing functions in cellular and animal tests. The facile method, high mass loading, high surface area, excellent wound-healing functions, interesting nanosheet/nanobelt structure, mass production potential, and NIR responsive properties of these T-RMFs indicate the great potential of our nanobelts for wound healing, tissue engineering, and much broader application areas. This facile nanosheet/nanobelt preparation strategy paves a new way for nanomaterial fabrication and applications.

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