Papers by Keyword: Electrospray

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Authors: Ken Finster, Robert Small, Andrea Belz, John Mahoney, Julius Perel, Jian Gong
Abstract: Conventional cleaning technologies have been effective in removal of particles, metals, and organic films. However, two trends motivating the development of new techniques are 1) the desire to minimize the environmental impact of large volumes of cleaning solutions; and 2) the need to clean at the sub-45 nm level, consistent with decreasing feature sizes. We report here on the initial characterization of a system to apply electrospray techniques to variants of the SC-1 and SC-2 solutions, as well as to solvent mixtures. We describe the generation of submicron sized droplets (<1 m radius) of cleaning mixtures and demonstrate a preliminary methodology, using a combination of experimental data and phenomenological modeling approaches, to characterize the physics of the droplet-surface interaction
Authors: Jeong Hwa Kim, Shi Joon Sung, Dae Kue Hwang
Abstract: A mesoporous TiO2 photo-electrode for dye-sensitized solar cells (DSSCs) was fabricated by an electrospray method using a solution of dispersed TiO2 nanocrystals (P25). A mesoporous TiO2 disk has a larger surface area than P25. The sub micrometer-sized TiO2 disk promotes light scattering, thereby increasing the photocurrent conversion efficiency. However, the electrosprayed TiO2 electrodes have many pores and disconnected electron pathways. Thus, we investigated the enhanced electrical contact of an electrosprayed TiO2 electrode using a hot-pressing process and a titanium tetrachloride (TiCl4) treatment process. After optimizing the post-treatment process of an electrosprayed TiO2 electrode, the cell shows conversion efficiency up to 6% at standard sunlight of AM 1.5.
Authors: A. Jaworek, A. Krupa, A.T. Sobczyk, M. Lackowski, T. Czech, Seeram Ramakrishna, S. Sundarrajan, Damian Pliszka
Abstract: The paper presents experimental results of electrospray deposition of nanopowder onto microfibers. The process is designed to form fibrous filters with an enhanced collection efficiency in the submicron range by covering the fabric with a catalytic material. Polyamide fibres were coated with Al2O3, ZnO, MgO, or TiO2 nanoparticles. The structures obtained were porous at the nanometer scale which increased the total surface area of the catalyst.
Authors: Wei Qian, Deng Guang Yu, Lu Wang, Shuo Lei Li, Yi Fan Wang, Cheng Long Wu, Xia Wang
Abstract: An electrospraying process was developed for fabricating a new type of microparticulate third generation solid dispersions (SDs) composed of multiple components with ferulic acid (FA) as a model active pharmaceutical ingredient. The spraying fluids were the co-dissolving solutions of FA, polyvinylpyrrolidone K25 (PVP K25) and sodium dodecyl sulfate (SDS) in 95% ethanol aqueous solutions. Field emission scanning electron microscopic observations showed that the microparticles had an average size of 1.47 ± 0.75 μm. Results from the differential scanning calorimetry analyses suggested that FA and SDS were distributed in the polymer matrix in an amorphous status owing to the compatibility among components resulted from the second-order interactions, as verified by attenuated total reflectance Fourier transform infrared spectra. In vitro dissolution tests demonstrated that the microparticulate SDs could release all the contained FA within 1 minute, extremely faster than the raw FA particles. It can be concluded that electrospraying is a useful tool for creating new generation SDs composed of multiple components for enhancing the rapid dissolution of poorly soluble drugs.
Authors: Mikihiko Kobayashi, Mitsuru Egashira, Takeshi Konno
Abstract: Polystyrene fibers were fabricated by electrospinning. Polystyrene resin was dissolved in chloroform, N,N-dimethylformamide, or their mixtures. In experiments with 10 wt-% solutions of polystyrene in various solvents, a 1:1 solvent mixture was found to be optimal. In the 1:1 solvent, an increase in polystyrene concentration resulted in a decrease in the number of beads on the electrospun fibers and an increase in their diameter. A 20 wt% solution of polystyrene gave fibers with a diameter of about 1.8 $m with almost no beads. Polystyrene fibers containing nanoparticles were prepared by electrospinning 20 wt% polystyrene solutions containing dispersed nanoparticles of TiO2 or ZnO. The concentrations of nanoparticles in the electrospun fibers, determined by energy dispersive X-ray spectroscopic analysis, were less than expected.
Authors: Damian Pliszka, S. Sundarrajan, A. Jaworek, A. Krupa, M. Lackowski, Seeram Ramakrishna
Abstract: We present a novel method of using Particle Image Velocimetry in electrospraying process studies. Electrospraying of metal oxides nanoparticles and covering nonwoven nanofiber mat creates composite material for potentially wide applications. Precise control of the electrospinning process gives possibility for better control of nanoparticles deposition and thereby enhancing its relative properties.
Authors: Jean Pascal Borra, A. Valt, Farzaneh Arefi-Khonsari, Michael Tatoulian
Abstract: We present a process for rapid post-discharge deposition of liquid monomer to form functional coatings at atmospheric pressure. The post-discharge polymerization of dense polyacid and polyether coatings is first depicted versus the energy density deposited by the preliminary surface treatment of polyethylene and polystyrene substrates in air Dielectric Barrier Discharge (DBD) with respect to SEM, to XPS and FTIR-ATR analysis and to polymerization yield determined by mass measurements. The paper focuses on the effect of the filamentary air DBD on surface of the polymer substrates and on post-discharge polymerization mechanism. Indeed, the grafting yield is shown to depend on the energy density deposited by DBD and on the time exposure to air between DBD and monomer deposition, controlling respectively the surface density of radicals and labile peroxides, both triggering the polymerization of vinyl precursors. Then, the effect of deposition conditions on the polymerization yield and related thickness of the functional polymer coatings is shown and special attention is paid to the stability of the coating upon washing.
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