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Polymer Silica Nanocomposite Gel Electrolytes for Lithium-Ion Batteries
Published in Prasanth Raghavan, Fatima M. J. Jabeen, Polymer Electrolytes for Energy Storage Devices, 2021
Akhila Das, Anjumole P. Thomas, Neethu T. M. Balakrishnan, Nikhil Medhavi, Jou-Hyeon Ahn, Fatima M. J. Jabeen, Prasanth Raghavan
Fumed silica, or pyrogenic silica, is a form of silica with a high surface area. This three-dimensional silica is formed by flame pyrolysis of silicon compounds. The silanol group (Si-O-H) in fumed silica imparts a hydrophilic nature to the material, facilitating the role of silica in many aqueous chemical reactions. In gel polymer electrolyte synthesis, this polar nature of the fumed silica is being utilized. In 1994, Saad et al. [35] introduced the concept of polymer composite electrolyte to enhance the ionic conductivity of polyethylene glycol (PEG) with fumed silica. In 1996, Tarascon et al. [36] reported increases in electrolyte uptake cyclability, and power density of LIBs constructed with graphite as the anode, lithium manganese oxide ( LiMn2O4, LMO ) as the cathode and the (PVdF-co-HFP/silica/1 M LiPF6 (EC/DMC)) as the electrolyte. Polymethyl methacrylate was photopolymerized with ethyl glycol dimethacrylate as a crosslinker with lithium perchlorate (LiClOj and fumed silica in EC/PC solvent [37]. Detailed investigations of the electrochemical impedance of polymeric membranes with and without silica indicates that incorporation of silica increases the Li+-ion conductivity and stability of the LIBs.
Nanostructures
Published in Elaine A. Moore, Lesley E. Smart, Solid State Chemistry, 2020
Elaine A. Moore, Lesley E. Smart
Nanoparticles have been known and used for centuries; think, for instance, of the pigments used to colour stained glass and ceramic glazes and of the colloidal gold particles used for making ‘ruby’ glass, known since Roman times. Within the modern era, fumed silica—small particles of silica—has been added to solids and liquids to improve their flow properties since the 1940s.
Fillers for Elastomer-Based Composite Materials: Synthesis and Characterization
Published in Nikolay Dishovsky, Mihail Mihaylov, Elastomer-Based Composite Materials, 2018
Nikolay Dishovsky, Mihail Mihaylov
Another method for the preparation of silica is the so-called fumed process. The preparation of the fumed silica consists of hydrolyzing silicon tetrachloride or tetrafluoride at 1000-1100°C by means of water vapor, that is, pyrolysis of tetrachloride is carried out in superheated vapor. The filler thus obtained is of a very stable morphology, highly dispersible, and with reactive ability.25, 28
Superhydrophobic poly(vinyl butyral) nanofibrous membrane containing various silica nanoparticles
Published in The Journal of The Textile Institute, 2019
Petra Peer, Martina Polaskova, Lenka Musilova
Fumed silica is an amorphous silicon dioxide derived synthetically under hydrolysis at high temperature. The average primary size of particle ranges from 7 to 40 nm, and these demonstrate the capability to aggregate and agglomerate relatively strongly, up to the form of large micron-sized clusters. The most important difference comprises variance in the density of the silanol group, reflected in the subsequent rheological characteristics. Converting the hydrophilic silica to hydrophobic is possible by placing some silane in a fluid bed reactor. Due to the reduced density of the silanol group, better dispersion behaviour is indicated in contrast with hydrophilic types. The nanofibrous membranes with controlled wettability by incorporating various types of silica nanoparticle into polyacrylonitrile solution were produced by Dufficy, Geiger, Bonino, and Khan (2015). Robust, superhydrophobic fabric coated by silica nanoparticles was prepared by Zhou et al. (2012) and Zhou, Wang, Niu, Gestos, and Lin (2013). Other researchers, Koysuren and Koysuren (2016) contained silica nanoparticles which boasted a high water contact angle and the capacity for dye adsorption. In order to enhance reaction of fibres to silica NPs, the Ar-plasma treatment can be used (Liu et al. 2017).
Polyacrylate/silica hybrid materials: A step towards multifunctional properties
Published in Journal of Dispersion Science and Technology, 2019
Fumed silica (pyrogenic silica) manufactured by high-temperature vapor process has occupied commercial significance due to several features such as large surface area and no porosity. Shekar et al.[35] proposed a kinetic model in order to have a better understanding of the gas-phase decomposition process of TEOS and particle dynamics. High surface area silica particles can also be synthesized by anion exchange using gel-type resins that act as templates as investigated by Tosheva et al.[95] Silica hollow spheres with low density and a large surface area can be synthesized using sacrificial templates[72] or ultrasonic spray pyrolysis method.[96] A dispersion polymerization technique has been employed by Chen et al.[73] for the synthesis of hollow particles using a one-step process where the formation of shell and core dissolution occurs simultaneously in an ethanol/water mixture. Porous silica beads with a controlled particle size in the range of 0.2–2.0 µm have been synthesized in situ by Unger et al.[97] for Capillary electrochromatography (CEC) applications.
Improving the recovery of clarification process of recombinant hepatitis B surface antigen in large-scale by optimizing adsorption-desorption parameters on Aerosil-380
Published in Preparative Biochemistry and Biotechnology, 2018
Seyed Nezamedin Hosseini, Parisa Ghaisari, Shahram Sharifnia, Maryam Khatami, Amin Javidanbardan
To date no comprehensive research considering a broad range of factors has been done for optimization of rHBsAg adsorption–desorption process on Aerosil for large-scale production. Fumed silica, which has joinery name of Aerosil, is made from flame pyrolysis of silicon tetrachloride or quartz sand vaporized in a 3000 ºC electric arc.[26] The produced powder has an extremely low bulk density and high surface area with above 99.8% SiO2 content. The three-dimensional structure of the powder results in increasing thixotropic behavior when used as a thickener or reinforcing filler. In the rHBsAg semi-purification process, Aerosil can yield significant benefits by reducing contaminants such as carbohydrates, lipids, and host-cell proteins.[24,25] Aerosil-assisted semipurification of rHBsAg was subject to batch adsorption at acidic pH on Aerosil matrix followed by elution from the matrix at basic pH.[12,23]