Coalescence of Water Drops in Water-ULSD Dispersions via Electrowetting

Coalescence of water droplets is an important phenomenon in many industrial applications. One approach for coalescing water droplets is by applying an external voltage across the drops. Coalescence occurs when spreading and motion of the drops due to the electrical field brings the drops into contact. Electrowettable surfaces were prepared with poly(styrene-co-methyl methacrylate) as the dielectric film and Fluropelâ„¢ as the hydrophobic surface layer. The surface of a stainless steel disk was coated in a way that the dielectric coating layer thickness varied with radial position with minimum thicknesses at the center and at the outer edge of the disk and a maximum at an intermediate radial position of the disk surface. The thickness gradient influenced the droplet movement and contributed to the coalescence. Two disks were assembled with a thin slit between the disks. Emulsions of water droplets in ultra low sulfur diesel fuel were pumped through the thin slit. Experiments showed significant increase in drop sizes when the disks were electrified compared to non-electrified disks

Functionalized Polyvinylidene Fluoride Electrospun Nanofibers and Applications

Electrospun polymeric nanofibers with flexible three-dimensional porous structures and high surface-to-volume ratio are potential resources for several novel applications in the fields of micro- and nanoscale filtration, water desalination, drug delivery, life sciences, catalysis, and energy harvesters. Functionalized polymeric fibers with enhanced molecular orientation, surface textural morphologies, and piezo-, pyro-, and ferroelectric properties are of technical and commercial interest around the world. Several emerging technologies including electrical polarization, vacuum plasma treatment, corona discharge, surface fluorination, and chemical treatments to functionalize the polyvinylidene fluoride nanofibers are discussed as potential applications of electroactive materials

Microscopy analysis and production rate data for needleless vertical rods electrospinning parameters

AbstractA multiple vertical rod setup for needless electrospinning was used to fabricate submicron polymer fibers. The design with multiple vertical rods is a new concept for increased production of electrospun fibers. Different geometries and operating conditions are possible. The effects of varying the number of rods in the array have been studied and reported [1]. The goal of this work was a proof of concept of the threaded rod design by exploring the effects of variations in applied voltage and gap distance for a fixed array of rods. Effects on fiber diameter and production rate of fibers are reported. More extensive experiments are needed to quantify the interrelations between parameters and to guide the design and operation of the method. No attempt was made to optimize the operating parameters or the geometry in terms of production rates or fiber diameters

Polarization of Electrospun PVDF Fiber Mats and Fiber Yarns

Electrospun fibers are of interest in a number of applications due to their small size, simplicity of fabrication, and ease of modification of properties. Piezoelectric polymers such as Polyvinylidene Fluoride (PVDF) can be charged when formed in the electrospinning process. This chapter discusses fabrication of PVDF fiber mats and fiber yarns and the measurement of their charge using a custom-made Faraday bucket. The results show the measured charge per mass of fiber mats was greater than the values measured for the yarns of the same mass. The measured charges may be related to both mass and external surface areas of the mats and yarn samples. It was observed the area/mass ratios of the fiber yarns were more than 30% less than the fiber mats

Palladium Nanoparticles Supported by Alumina Nanofibers Synthesized by Electrospinning

Palladium nanoparticles supported by alumina nanofibers have been successfully synthesized by electrospinning using palladium chloride incorporated into a solution of polyvinyl pyrrolidone and aluminum acetate. Palladium agglomerate sizes and the surface morphology of the electrospun nanofibers were determined by transmission electron microscopy. Palladium nanoparticles appeared to be well dispersed within the electrospun nanofiber structure. X-ray diffraction, x-ray photoelectron spectroscopy, and Raman scattering spectroscopy techniques were used to identify the crystalline form and distinguish between oxidized and metallic palladium particles after heating and hydrogenation

Electrical, Structural, and Chemical Properties of Semiconducting Metal Oxide Nanofiber Yarns

The electrical, structural, and chemical properties of twisted yarns of metal-oxide nanofibers, fabricated using a modified electrospinning technique, are investigated in this report. In particular, synthesized zinc oxide and nickel oxide yarns having diameters in the range of 4-40 mu m and lengths up to 10 cm were characterized, whose constituent nanofibers had average diameters of 60-100 nm. These yarns have one macroscopic dimension for handling while retaining some of the properties of nanofibers. (C) 2008 American Institute of Physics

A Versatile Microparticle-Based Immunoaggregation Assay for Macromolecular Biomarker Detection and Quantification

The rapid, sensitive and low-cost detection of macromolecular biomarkers is critical in clinical diagnostics, environmental monitoring, research, etc. Conventional assay methods usually require bulky, expensive and designated instruments and relative long assay time. For hospitals and laboratories that lack immediate access to analytical instruments, fast and low-cost assay methods for the detection of macromolecular biomarkers are urgently needed. In this work, we developed a versatile microparticle (MP)-based immunoaggregation method for the detection and quantification of macromolecular biomarkers. Antibodies (Abs) were firstly conjugated to MP through streptavidin-biotin interaction; the addition of macromolecular biomarkers caused the aggregation of Ab-MPs, which were subsequently detected by an optical microscope or optical particle sizer. The invisible nanometer-scale macromolecular biomarkers caused detectable change of micrometer-scale particle size distributions. Goat anti-rabbit immunoglobulin and human ferritin were used as model biomarkers to demonstrate MP-based immunoaggregation assay in PBS and 10% FBS to mimic real biomarker assay in the complex medium. It was found that both the number ratio and the volume ratio of Ab-MP aggregates caused by biomarker to all particles were directly correlated to the biomarker concentration. In addition, we found that the detection range could be tuned by adjusting the Ab-MP concentration. We envision that this novel MP-based immunoaggregation assay can be combined with multiple detection methods to detect and quantify macromolecular biomarkers at the nanogram per milliliter level. DOI: 10.1371/journal.pone.011504

Electrospinning Route for the Fabrication of P-n Junction Using Nanofiber Yarns

Electrospinning is a simple, versatile, and cost effective method for generating nanoscale fibers, wires, and tubes. Nanowires and nanotubes could be important building blocks for nanoscale electronics, optoelectronics, and sensors as they can function as miniaturized devices as well as electrical interconnects. We report on a simple method to fabricate free standing ceramic nanofiber heterostructures, which exhibit rectifying behavior of a p-n junction

Optical properties of the vibrations in charged C60_{60} molecules

The transition strengths for the four infrared-active vibrations of charged C$_{60}$ molecules are evaluated in self-consistent density functional theory using the local density approximation. The oscillator strengths for the second and fourth modes are strongly enhanced relative to the neutral C$_{60}$ molecule, in good agreement with the experimental observation of ``giant resonances'' for those two modes. Previous theory, based on a ``charged phonon'' model, predicted a quadratic dependence of the oscillator strength on doping, but this is not borne out in our calculations.Comment: 10 pages, RevTeX3.

A Versatile Microparticle-Based Immunoaggregation Assay for Macromolecular Biomarker Detection and Quantification

The rapid, sensitive and low-cost detection of macromolecular biomarkers is critical in clinical diagnostics, environmental monitoring, research, etc. Conventional assay methods usually require bulky, expensive and designated instruments and relative long assay time. For hospitals and laboratories that lack immediate access to analytical instruments, fast and low-cost assay methods for the detection of macromolecular biomarkers are urgently needed. In this work, we developed a versatile microparticle (MP)-based immunoaggregation method for the detection and quantification of macromolecular biomarkers. Antibodies (Abs) were firstly conjugated to MP through streptavidin-biotin interaction; the addition of macromolecular biomarkers caused the aggregation of Ab-MPs, which were subsequently detected by an optical microscope or optical particle sizer. The invisible nanometer-scale macromolecular biomarkers caused detectable change of micrometer-scale particle size distributions. Goat anti-rabbit immunoglobulin and human ferritin were used as model biomarkers to demonstrate MP-based immunoaggregation assay in PBS and 10% FBS to mimic real biomarker assay in the complex medium. It was found that both the number ratio and the volume ratio of Ab-MP aggregates caused by biomarker to all particles were directly correlated to the biomarker concentration. In addition, we found that the detection range could be tuned by adjusting the Ab-MP concentration. We envision that this novel MP-based immunoaggregation assay can be combined with multiple detection methods to detect and quantify macromolecular biomarkers at the nanogram per milliliter level