Weight Of Polyvinylpyrrolidone Research Articles

Morphological Modulation of Electrospun PVDF/PVP Nanofibers

ABSTRACTIn electrohydrodynamics, the regulation of the morphology and structures of electrospun nanofibers is crucial for tuning the properties of the final product. In the electrospinning process, the uniform and smooth morphology of polyvinylidene fluoride (PVDF) nanofibers can be obtained by controlling experimental parameters, environmental parameter, and system parameters. However, there is inadequate research on the effect of polymer addition on the morphology enhancement of PVDF nanofibers and the underlying mechanisms. In this study, the effects of the polyvinylpyrrolidone (PVP) molecular weight and content on various process parameters (i.e., Taylor cone length, straight fluid jet length, and spray angle) are evaluated. The obtained electrospun PVDF/PVP nanofibers were further characterized by SEM, EDS, FTIR, and XRD. The results indicate that the solution viscosity, which was controlled by varying the molecular weight and content of PVP, was linearly correlated with the process parameters. As the PVP molecular weight and content increased, the nanofiber diameter increased and the nanofiber morphology became smoother. The EDS results revealed that the nanofibers consisted of PVDF encapsulated by PVP. The FTIR and XRD results indicated that hydrogen bonding between PVP and PVDF weakened the crystallization of PVDF, leading to the formation of smooth PVDF/PVP nanofibers.

Features of the Formation of a Reinforcing Coating on Hydrogel Membranes Based on Polyvinylpyrrolidone Copolymers

This paper presents the study results of formation features of composite hydrogel/polyamide membranes obtained by modification of hydrogel films based on 2-hydroxyethylmethacrylate (HEMA) and polyvinylpyrrolidone (PVP) copolymers. The formation process of composite two-layer membranes was carried out in two stages: obtaining hydrogel membrane substrates followed by their modification with an ultra-thin layer based on a mixture of polyamide (PA) with PVP. The main task of the work was to investigate the possibility of forming a modifying PA/PVP coating on the surface of hydrogel films and to obtain composite hydrogel membranes with the required strength and osmotic permeability based on them. For the formation of composite two-layer membranes, PVP with MM = 12 × 103 g/mol and MM = 360 × 103 g/mol were used. Additional use of PVP in the modifying solution contributes to the process of its penetration into the hydrogel substrate. Together with the formation of a reinforcing layer, this ensures the obtainment of hydrogel films of increased strength, with the possibility of directional regulation of their diffusion permeability. It was found that the main factors affecting the nature of the interaction between the layers of the obtained composite films, as well as their physico-mechanical and sorption–diffusion properties, are the HEMA:PVP ratio in the original polymer–monomer composition (PMC), the formulation of the reinforcing layer, the duration of the modification process and the molecular weight of PVP in PMC and in the modifying solution. The strength and water content of two-layer composite hydrogel/polyamide membranes, as well as their salt and water permeability coefficients, are the highest in the case of using high-molecular weight PVP (MMPVP = 360 × 103 g/mol) and low-molecular weight (MMPVP = 12 × 103 g/mol) during the synthesis of the hydrogel substrate to obtain a PA-6/PVP solution for forming a reinforcing layer.

Effect of PVP Molecular Weights on the Synthesis of Ultrasmall Cus Nanoflakes: Synthesis, Properties, and Potential Application for Phototheranostics.

Copper sulfide nanoparticles (CuS) hold tremendous potential for applications in photothermal therapy (PTT) and photoacoustic imaging (PAI). However, the conventional chemical coprecipitation method often leads to particle agglomeration issues. To overcome this challenge, we utilized polyvinylpyrrolidone (PVP) as a stabilizing agent, resulting in the synthesis of small PVP-CuS nanoparticles named PC10, PCK30, and PC40. Our study aimed to investigate how different molecular weights of PVP influence the nanoparticles' crystalline characteristics and essential properties, especially their photoacoustic and photothermal responses. While prior research on PVP-assisted CuS nanoparticles has been conducted, our study delves deeper into this area, providing insights into optical properties. Remarkably, all synthesized nanoparticles exhibited a crystalline structure, were smaller than 10 nm, and featured an absorbance peak at 1020 nm, indicating their robust photoacoustic and photothermal capabilities. Among these nanoparticles, PC10 emerged as the standout performer, displaying superior photoacoustic properties. Our photothermal experiments demonstrated significant temperature increases in all cases, with PC10 achieving an impressive efficiency of 51%. Moreover, cytotoxicity assays revealed the nanoparticles' compatibility with cells, coupled with an enhanced incidence of apoptosis compared to necrosis. These findings underscore the promising potential of PVP-stabilized CuS nanoparticles for advanced cancer theranostics.

Polyvinylpyrrolidone – KNNLST lead-free ceramic composites for dielectric applications

Piezoelectric composites offer many advantages compared to piezoelectric ceramics or polymers because of their mechanical flexibility and relatively high stress-induced voltage. In this research, high-molecular weight polyvinylpyrrolidone (PVP) and lead-free piezoelectric (K0.45Na0.51Li0.04) (Nb0.85Ta0.1Sb0.05)O3 (KNNLST) ceramics have been used to produce composites. The possible range of composites from 0 to 100 wt% has been explored. The ceramics were produced using conventional processing methods, while the composites were solution-cast after being mixed with a magnetic stirrer. The composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and dielectric and piezoelectric characterization to determine their properties. The morphology of the composites indicates the homogeneous distribution of the ceramics in the polymer. The XRD patterns show that the dissolved amorphous PVP precipitates and the addition of KNNLST ceramics contributes substantially to the crystalline phase formation. The relative permittivity and loss tangent values increase with an increase in ceramic content. Acceptable polarization and strain hysteresis curves were obtained only for the KNNLST ceramics. The composites produced will be suitable for dielectric applications.

Influence of polyvinylpyrrolidone (PVP) in the synthesis of luminescent NaYF4:Yb,Er upconversion nanoparticles

Polyvinylpyrrolidone (PVP) can be used to produce upconversion nanoparticles (UCNPs) in an advantageous manner, i.e. at modest temperatures in open-to-air conditions with simple hotplate and flask apparatus. However, the influence of PVP parameters on the formation of UCNPs has not been previously investigated. In this exploratory study, we establish that PVP molecular weight and relative amount of PVP can greatly influence the morphology and diameter of NaYF4:Yb,Er UCNPs produced via the PVP-assisted route. At nominal amounts of PVP, varying the molecular weight of PVP in synthesis between 10,000 g mol−1 (PVP10), 40,000 g mol−1 (PVP40), and 55,000 g mol−1 (PVP55), had minimal effect on UCNP morphology, whereas reducing the quantity of PVP10 and PVP40 in the reaction to 10% of the nominal amount resulted in two notable effects: (1) the generation of a greater range of UCNP diameters and (2) the production of an unexpected sub-population of rhombus-shaped UCNPs. Bulk and individual nanoparticle analysis indicates that all UCNP morphologies were cubic (α-phase) crystal structure and consisted of NaYF4:Yb,Er. Optical emission properties exhibited only modest green and red luminescence emission ratio when PVP parameters were varied. However, separately produced PVP40 NaYF4:Yb,Tm UCNPs exhibited a much more intense and dual-band blue/red emission. This exploratory work demonstrates that tailoring PVP content in synthesis of UCNPs can greatly alter morphology of UCNPs produced and should be carefully considered in experimental design. However, the underlying mechanisms of action of the role PVP plays in this synthesis remain unclear. Ultimately, significant further work is still required to fully elucidate the relevant chemistry to achieve full control of PVP-UCNP synthesis.

Effect of molecular weight and content of polyvinylpyrrolidone on cell proliferation, loading capacity and properties of electrospun green tea essential oil-incorporated polyamide-6/polyvinylpyrrolidone nanofibers

Electrospun nanofibers demonstrate a novel category of materials that display great potential in numerous biomedical applications including tissue engineering, drug delivery, regenerative medicine, and wound healing. Here, composite nanofibrous scaffolds of polyamide-6 (PA-6), polyvinylpyrrolidone (PVP), and tea tree oil (TTO) was fabricated by electrospinning method and the effect of various molecular weight of PVP on properties of produced fiber scaffolds was studied. The investigations showed that the increase in the molecular weight of PVP, as well as the decrease in its content provides the thinner fibers (220.90 ± 59.0 nm) with higher porosity (∼90%), high water vapor transmission rate (WVTR) (3945. g/m2.24 h), and low surface wettability (∼85°). The morphological investigation accomplished with scanning electron microscope (SEM) showed the uniform bead-free electrospun fibers scaffold. The structural characteristics of the produced scaffolds were investigated with Fourier Transform Infrared Spectroscopy (FTIR). The results of the mechanical test of the produced fibers confirmed their ability to protect the wound area against external forces during the healing process. Antibacterial and antioxidant tests of samples containing TTO showed excellent and strong activities. Besides, the in vitro cytotoxicity, and cell adhesion was evaluated, that the obtained results illustrated that the electrospun fibers were biocompatible and supported cell adhesion. Based on the findings, this new electrospun matrix is expected to be effective as a potential wound dressing for skin regeneration.

A Novel One-Pot Synthesis of PVP-Coated Iron Oxide Nanoparticles as Biocompatible Contrast Agents for Enhanced T2-Weighted MRI

A contrast agent with specific characteristics is essential for high-quality magnetic resonance imaging (MRI). It plays a crucial role in enhancing the visibility of certain tissues and structures, making it imperative for diagnostic procedures. Superparamagnetic iron oxide nanoparticles (SPIONs) have emerged as a promising alternative to traditional contrast agents for MRI due to their non-toxicity and superior magnetic properties. However, a suitable surface coating strategy is needed to produce polymer-coated SPIONs with controllable sizes in order to enhance their stability and biocompatibility. This study presents a novel one-pot synthesis method for the production of highly stable polyvinylpyrrolidone (PVP)-coated SPIONs. By systematically manipulating the physicochemical properties of SPIONs, the effect of different molecular weights of PVP was studied. The results showed that SPIONs coated with PVP with molecular wight 40,000 g/mol (40 K) exhibited a high magnetization (Ms = 48.4 emu/g), an average size distribution (11.61 nm), and excellent stability. The relaxivity of coated and uncoated SPIONs was investigated using MRI images. The results revealed that the (r2/r1) ratio of PVP40K-SPIONs was 72.55, compared to 55.72 for the bare SPIONs, making them a highly promising T2-contrast agent for future development of MRI applications. This study opens new avenues for the development of biocompatible and stable SPIONs for improved medical diagnostic and imaging.

Fabrication of micro/nano spherulitic hierarchical energetic materials via noncrystallographic branching induced by polymer additives: A case study of 2,2′,4,4′,6,6′-hexanitrostilbene (HNS)

In this work, the micro/nano spherulitic hierarchical 2,2′,4,4′,6,6′-hexanitrostilbene (HNS) with the excellent specific surface area was prepared for the first time, which was expected to overcome the agglomeration problems of nanoscale HNS. In detail, poly(N-isopropyl acrylamide) (PNIPAM), polysuccinimide (PSI), and polyvinylpyrrolidone (PVP) were selected as additives to induce forming spherulitic HNS. Leaflike crystals were obtained in the presence of PNIPAM, while spherulitic HNS could be fabricated in the presence of PSI or PVP. And the prepared spherulitic HNS owned nearly 6 times the specific surface area of the raw HNS, with decreased impact sensitivity and advanced melting and decomposition temperatures, demonstrating a good desensitization effect, and a favorable energy release of the hierarchical structure. Moreover, morphological changes under the effect of the molecular weight and concentration of PVP were explored. The approximated morphological evolution of spherulitic HNS was consistent with the classical spherulitic growth by noncrystallographic branching. Furthermore, it was verified that preferential adsorption of PVP and PSI on the HNS inhibits the growth steps of the (200) face and introduces stress to generate crystal defects, which triggers noncrystallographic branching and further spherulitic growth. Overall, the strategy of fabricating micro/nano spherulitic hierarchical energetic materials via polymer-additive induced noncrystallographic branching is promising to solve the problems of nanoscale energetic materials in agglomeration and microscale bulk crystals in low activity.

MODIFICATION OF PROTON PUMP MEMBRANE USING POLYVINYLPYRROLIDONE (PVP) FOR POTENTIAL TOTAL ALKALINITY SENSING

Total alkalinity is one of the important parameter in the regulation of seawater carbonate chemistry system to determine the capacity of water to neutralize acid. In this paper, a new proton pump membrane was successfully modified using polyvinylpyrrolidone (PVP) as a supporting material due to its excellent chemical properties. The surface morphology of the membrane was thoroughly studied using Scanning Electron Microscope (SEM), which showed the presence of pore structure, ascribed to the presence of low molecular weight of PVP. The absorption of membrane was studied using Ultraviolet-Visible (UV-Vis) spectrophotometer, where the peak appeared at 539 nm-1. The functional group of the modified membrane was analyzed using Fourier Transform Infrared Spectroscopy (FTIR), and the spectra showed almost similar between modified membrane with PVP and without PVP. The electrochemical behaviour of the membrane was evaluated by cyclic voltammetry (CV) using gold (Au) electrode and the resulting voltammogram showed that the modified membrane with PVP has higher current reading compared to the membrane without PVP, indicating that there is redox reaction occured during the immobilization. The condition and perfomance of modified proton pump membrane with PVP was compared and analyzed.

ВПЛИВ МОЛЕКУЛЯРНОЇ МАСИ ПОЛІВІНІЛПІРОЛІДОНУ НА СОРБЦІЙНІ ТА ФІЗИКО-МЕХАНІЧНІ ВЛАСТИВОСТІ ГІДРОГЕЛЬ/ПОЛІКАПРОАМІДНИХ ДВОШАРОВИХ МЕМБРАН

The paper presents the study results of the molecular weight effect of polyvinylpyrrolidone (PVP) on the properties of composite hydrogels/polycaproamide membranes, which were obtained by modifying hydrogel films based on copolymers of 2-hydroxyethylmethacrylate (HEMA) with PVP by applying ultra- thin layers on the basis of a polyamide (PA-6) with PVP mixture. It was found that the interaction magnitude between the layers of composite membranes, as well as their properties – water content, tensile strength, salt and water permeability coefficients, largely depend on the molecular weight of PVP as in the original polymer-monomer composition and in the modifying PA-6/PVP solution.

Polyvinylpyrrolidone-mediated Co3O4 microspheres assembled in size-tunable submicron spheres with porous core-shell structure for high-performance gases sensing

Metal-organic frameworks (MOFs) derived cobalt oxide (Co3O4) microspheres assembled in size-tunable submicron spheres with porous core-shell structure are regulated by adjusting the amount in different weight of polyvinylpyrrolidone (PVP) and successfully fabricated via a combined hydrothermal and calcination method. Gas sensing mechanism toward ethanol and acetone with 0.10 of PVP, indicates that the sensor based on complex hierarchical structure can display long-term durability and outstanding responsiveness at operating temperatures of 180 and 200 °C. The formation of the special structure labeled as C/Co-P(0.10) − 350 and the ultra-high sensing capability are attributed to the presence of surface-adsorbed oxygen molecules with chemical activity induced by the hierarchical configuration. Herein, the strategy whereby the surface-adsorbed oxygen molecules contribute toward enhancing the gas sensing performance, is a novel route for the development of high-performance sensing materials.

The structural and figure of merit photodetector of PVP-doped with lanthanum

This study describes the fabrication and characterization of PVP and PVP/La thin films from a mixture of high molecular weight polyvinylpyrrolidone (PVP) and (1, 2, and 3)% lanthanum chloride using an electrospinning process on glass and silicon. It includes an N- type (Si) (111) substrate at room temperature. Field Emission Scanning Electron Microscopy (FESEM) analysis reveals fibers with an average diameter in the range of 125-250 nm. The mean fiber diameter decreases with increasing concentration (La). The optical energy gap was determined from the analysis of the transmission spectrum in the UV-visible region. The optical gap (Eg) gradually decreases from 4 eV to 3.64 eV for undoped PVP films due to the increase in La ion content at 3%, which determines the feasibility of using these obtained fibers in the manufacturing process. PVP/La nanofibers as detectors.

Fabrication, characterization, and performance of poly (aryl ether nitrile) flat sheet ultrafiltration membranes with polyvinyl pyrrolidone as additives

Abstract Poly(aryl ether nitrile) (PEN) was used to fabricate ultrafiltration membrane via immersion precipitation phase inversion method. The effects of polyvinyl pyrrolidone (PVP) of different molecular weights and concentrations on the structure and performance of PEN membranes were investigated. The membranes were observed by scanning electron microscope, atomic force microscope, equilibrium water content (EWC), porosity (ε), and so on. The membranes were subjected to ultrafiltration characterizations such as pure water flux (PWF), compaction factor (CF), hydraulic permeability (P m), and bovine serum albumin (BSA) rejection rate. The hydrophilicity was characterized by infrared spectroscopy and contact angle tests. Results showed that molecular weight of PVP had significant effect on PEN membrane formation, which the membrane prepared by PVP-k30 exhibited excellent comprehensive performance. Meanwhile, the concentration of PVP-k30 could effectively control the select-permeability of PEN membrane. With PVP-k30 concentration increased from 7 to 13 wt%, the prepared PEN membranes got higher EWC, ε, CF, and P m. The PWF increased from 146.5 to 249.1 L m−2 h−1 bar−1, while the overall rejection of BSA remained above 90%. Further increasing the addition amount to 16 wt%, the membrane performance began to decline. Finally, the addition of PVP-k30 could effectively improve the hydrophilicity of prepared PEN membrane surface.

Investigating the Potential of Ethyl Cellulose and a Porosity-Increasing Agent as a Carrier System for the Formulation of Amorphous Solid Dispersions.

In the present work, an insoluble polymer, i.e., ethyl cellulose (EC), was combined with the water-soluble polyvinylpyrrolidone (PVP) as a carrier system for the formulation of amorphous solid dispersions. The rationale was that by conjoining these two different types of carriers a more gradual drug release could be created with less risk for precipitation. Our initial hypothesis was that upon contact with the dissolution medium, PVP would be released, creating a porous EC matrix through which the model drug indomethacin could diffuse. On the basis of observations of EC as a coating material, the effect of the molecular weight of PVP, and the ratio of EC/PVP on the miscibility of the polymer blend, the solid state of the solid dispersion and the drug release from these solid dispersions were investigated. X-ray powder diffraction, modulated differential scanning calorimetry, and solid-state nuclear magnetic resonance were used to unravel the miscibility and solid-state properties of these blends and solid dispersions. Solid-state nuclear magnetic resonance appeared to be a crucial technique for this aspect as modulated differential scanning calorimetry was not sufficient to grasp the complex phase behavior of these systems. Both EC/PVP K12 and EC/PVP K25 blends were miscible over the entire composition range, and addition of indomethacin did not alter this. Concerning the drug release, it was initially thought that more PVP would lead to faster drug release with a higher probability that all of the drug molecules would be able to diffuse out of the EC network as more pores would be created. However, this view on the release mechanism appeared to be too simplistic as an optimum was observed for both blends. On the basis of this work, it could be concluded that drug release from this complex ternary system was affected not only by the ratio of EC/PVP and the molecular weight of PVP but also by interactions between the three components, the wettability of the formulations, and the viscosity layer that was created around the particles.

Chronic Kidney Disease from Polyvinylpyrrolidone Deposition in Persons with Intravenous Drug Use.

Persons with intravenous drug use have a higher risk of developing CKD compared with the general population. In Norway, deposits of polyvinylpyrrolidone have been observed in kidney biopsies taken from persons with opioid addiction and intravenous drug use since 2009. Polyvinylpyrrolidone is an excipient commonly used in pharmaceuticals, and the polyvinylpyrrolidone deposits observed in these patients were caused by intravenous injection of a specific oral methadone syrup containing very high molecular weight polyvinylpyrrolidone. Here, we present the clinicopathologic findings from 28 patients with CKD associated with polyvinylpyrrolidone deposition in the kidney. The 28 patients and their kidney biopsies were included when polyvinylpyrrolidone deposition was recognized, either retrospectively or at the time of diagnostic evaluation. Biopsies were taken between 2009 and 2016. We collected laboratory parameters and clinical data from digital patient charts. For each kidney biopsy, the glomerular volume, extent of polyvinylpyrrolidone deposition, and tubulointerstitial area with tubular atrophy were assessed quantitatively. All patients (mean age: 37 years) had CKD (mean eGFR: 33 ml/min per 1.73 m2) and normal urine protein or non-nephrotic-range proteinuria. Biopsies showed moderate to severe tubular atrophy (mean extent: 65%) and interstitial infiltrates of vacuolated macrophages containing polyvinylpyrrolidone (mean share of biopsy area: 1.5%). Underperfused and ischemic glomeruli were common findings. In 22 samples, ultrastructural investigation revealed polyvinylpyrrolidone-containing vacuoles in the mesangial or endothelial cells of glomeruli. At the last follow-up, most patients had stable or improved eGFR. Two patients had developed kidney failure and underwent hemodialysis. Intravenous injection of a specific oral methadone syrup caused polyvinylpyrrolidone deposition in the kidney in persons with opioid addiction and intravenous drug use. Kidney biopsy findings suggested an association between polyvinylpyrrolidone deposition and tubular atrophy.

Synthesis of silver nanorings through a glycerol-base polyol method

Silver nanoring, a new nanomaterial with special morphology, exhibits attractive potential in optoelectronics applications. In this work, a glycerol-base modified polyol method is investigated. Using this method, silver nanorings with perfect geometry and ring diameter range from 6.54 to 30.67ss μm, wire diameter of 66.7-115.5 nm were synthesized by replacing EG with glycerol and adjusting the molecular weight and concentration of polyvinylpyrrolidone (PVP). The growth mechanism and factors that affect the morphology were studied in detail. The formation of silver nanorings showed high dependence on the viscosity of solution, wire diameter of AgNWs and the molecular weight of PVP.

Revisiting the preparation of cylindrical polystyrene particles by magnetic stirring

The cylindrical shape is one of the most common shapes in geometry. The preparation of cylindrical polystyrene (PS) particles by magnetic stirring has been previously reported (Angew. Chem. Int. Ed.2018, 57, 9936–9940) via two steps: spherical PS particles were synthesized by dispersion polymerization of styrene with polyvinylpyrrolidone (PVP) as the stabilizer, followed by stirring the spherical PS particles in a water medium in the presence of PVP. However, the effects of various parameters on the deformation were not fully investigated. Herein we report full details of the preparation of cylindrical PS particles by stirring at room temperature. The influence of PVP molecular weight in the polymerization process, and various stirring parameters such as the molecular weight of PVP for stirring, concentration of PVP for stirring, stirring time, stirring rate, size of stirrer and amount of the mixture for stirring on the morphology of the resulting particles was investigated systematically. Moreover, a larger glass vial and correspondingly a larger magnetic stirrer were used in this work, which could produce cylindrical polymer particles at a five-fold larger scale. However, the production of cylindrical polymer particles at a even (fifty-fold) larger scale was less successful and might lead to a substantial part of peanut-shaped particles. This work is expected to be useful for improved understanding of the formation of these cylindrical polymer particles.

Formation of copper oxide II in polymer solution-blow-spun fibers and the successful non-woven ceramic production

Copper oxide II is a p-type semiconductor that can be used in several applications. Focusing on producing such material using an easy and low-cost technique, we followed an acetate one-pot-like route for producing a polymer precursor solution with different acetates:PVP (polyvinylpyrrolidone) weight ratios. Then, composite nanofibers were produced using the solution blow spinning (SBS) technique. The ceramic CuO samples were obtained after a calcination process at 600 °C for 2 h, applying a heating rate of 0.5 °C/min. Non-woven fabric-like ceramic samples with average diameters lower than 300 nm were successfully obtained. SEM images show relatively smooth fibers with a granular morphology. XRD shows the formation of randomly oriented grains of CuO. In addition, FTIR and XRD analyses show the CuO formation before the heat treatment. Thus, a chemical reaction sequence was proposed to explain the results.

Production and qualification of an electrospun ceramic nanofiber material as a candidate future high power target

In an effort to develop and design next generation high power target materials for particle physics research, the possibility of fabricating nonwoven metallic or ceramic nanofibers by electrospinning process is explored. A low-cost electrospinning unit is set up for in-house production of various ceramic nanofibers. Yttria-stabilized zirconia nanofibers are successfully fabricated by electrospinning a mixture of zirconium carbonate with high-molecular weight polyvinylpyrrolidone polymer solution. Some of the inherent weaknesses of electrospinning process like thickness of nanofiber mat and slow production rate are overcome by modifying certain parts of electrospinning system and their arrangements to get thicker nanofiber mats of millimeter order at a faster rate. Continuous long nanofibers of about hundred nanometers in diameter are produced and subsequently heat treated to get rid of polymer and allow crystallize zirconia. Specimens were prepared to meet certain minimum physical properties such as thickness, structural integrity, thermal stability, and flexibility. An easy innovative technique based on atomic force microscopy was employed for evaluating mechanical properties of single nanofiber, which were found to be comparable to bulk zirconia. Nanofibers were tested for their high-temperature resistance using an electron beam. It showed resistance to radiation damage when irradiated with 1 MeV ${\mathrm{Kr}}^{2++}$ ion. Some zirconia nanofibers were also tested under high-intensity pulsed proton beam and maintained their structural integrity. This study shows for the first time that a ceramic nanofiber has been tested under different beams and irradiation condition to qualify their physical properties for practical use as accelerator targets. Advantages and challenges of such nanofibers as potential future targets over bulk material targets are discussed.

Optical Oxygen Sensor Patch Printed with Polystyrene Microparticles-based Ink on Flexible Substrate.

Optical oxygen sensors based on photoluminescence quenching have gained increasing attention as a superior method for continuous monitoring of oxygen in a growing number of applications. A simple and low-cost fabrication technique was developed to produce sensor arrays capable of two-dimensional oxygen tension measurement. Sensor patches were printed on polyvinylidene chloride film using an oxygen-sensitive ink cocktail, prepared by immobilizing Pt(II) mesotetra(pentafluorophenyl)porphine (PtTFPP) in monodispersed polystyrene microparticles. The dispersion media of the ink cocktail, high molecular weight polyvinyl pyrrolidone suspended in 50% ethanol (v/v in water), allowed adhesion promotion and compatibility with most common polymeric substrates. Ink phosphorescence intensity was found to vary primarily with fluorophore concentration and to a lesser extent with polystyrene particle size. The sensor performance was investigated as a function of oxygen concentrations employing two different techniques: a multi-frequency phase fluorometer and smart phone-based image acquisition. The printed sensor patch showed fast and repetitive response over 0-21% oxygen concentrations with high linearity (with R2 >0.99) in a Stern-Volmer plot, and sensitivity of I0/I21 >1.55. The optical sensor response on a surface was investigated further using two-dimensional images which were captured and analyzed under different oxygen environment. Printed sensor patch along with imaging read-out technique make an ideal platform for early detection of surface wounds associated with tissue oxygen.