Capacitor dielectrics polymer films

Early capacitors were usually made with paper or mica. Paper was used for large capacitance values and mica was used for high-frequency capacitors. With the advent of commercial polymer film production, these increasingly available materials became popular as capacitor dielectrics. Polymer films are ideally suited for capacitor manufacture because they ... 

A DEA is basically a compliant capacitor where an incompressible, yet highly deformable, dielectric elastomeric material is sandwiched between two complaint electrodes. The electrodes are designed to be able to comply with the deformations of the elastomer and are generally made of a conducting material such as a colloidal carbon in a polymer binder, graphite spray, thickened electrolyte solution, etc. Dielectric elastomer films can be fabricated by conventional... 

Essentially polymer-film capacitors comprise dielectric films (polymer or paper or both together) interleaved with aluminium electrodes, either as aluminium foil or, more commonly, in the form of a layer evaporated directly on the dielectric, and rolled together. They are sealed in an aluminium can or in epoxy resin. Because the dielectric films and evaporated electrodes have thicknesses of only a few microns and about 0.025 /mi respectively, volumetric efficiencies can be high. The dielectric films are polystyrene, polypropylene, polyester, polycarbonate or paper paper dielectrics are always impregnated with an insulating liquid. 

Another contacting thickness measurement is the capacitance measurement. Metal plates are placed at either side of the polymer film. Thus, the material and plates form a capacitor, with the polymer acting as a dielectric. Since the capacitance depends on the thickness of the dielectric, the material thickness is determined by measuring the capacitance. The problem in applying this technique to extrusion is that it will be difficult to establish good contact between polymer and metal plates, particularly in continuous monitoring of thickness. 

Many polymer films have been examined as capacitor dielectrics but those principally used are polyethylene terephthalate, polystyrene, polycarbonate, polytetrafluoroethylene, polyimides and polypara-xylylene. A number of these materials are more familiar by their trade names ... 

The increase in dielectric constant is attributed to the formation of many small capacitors of fillers (electrodes) with a dielectric thin polymer film between them, which can increase the dielectric constant. The distribution of the fillers inside of the polymer can highly affect the dielectric constant. The filler distribution depends on nanocomposite preparation techniques. 

The main commercial use of solid SiO is as a vapor-deposition material for the production of SiOx thin films for optical or electronic applications (antireflective coatings, interference filters, beam-splitters, decorative coatings, dielectric layers, isolation layers, electrodes, thin-film capacitors, thin-film transistors, etc.), for diffusion barrier layers on polymer foils or for surface protection layers.Other uses for SiO have been proposed, such as the substitution of elemental silicon in the Muller-Rochow process for the production of organosilicon halides, because solid SiO can be produced at lower temperatures than elemental silicon. 

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