Films poly

Figure 1. Spectroscopic changes upon hyproperoxidation of EPDM (POLY) films, exposure times each 20 min. (a) hydroperoxide grow (b) and (c) anthracene loss. 

So far, we have ignored the primary reason poly films are used in integrated circuits. Heavily-doped poly is used as a gate electrode, and the electrical conductivity of this material is of prime importance. Therefore, we have to inquire into the feasibility of doping poly as it is being deposited by CVD. 

Many publications describe the stress behavior of LPCVD-poly films. However, to our knowledge, no comprehensive and complete publication on the processing parameters that affect the stress profile within these layers is available. 

Information on parameters that influence stress gradients in LPCVD-poly is less readily available. However, one study showed that the grain growth that occurs during annealing of heavily doped films reduces the stress gradient in LPCVD-poly films [24]. 

The stability of the properties of polysilicon films to processing is not ideal. The structure and intrinsic stress of LPCVD-poly films created by different organizations but with the same deposition recipe were different [21]. The properties of LPCVD-poly can differ even on wafers from the same deposition run, due to small temperature fluctuations in the deposition furnace [25]. However, since several LPCVD-poly surface-micromachined sensors are in fact produced in high volumes for the automotive industry (e.g., by Analog Devices, Infineon, and Motorola), these literature data may not represent the current state of the art. 

Used to facilitate multiple repositioning of the lateral tape without tearing the back sheet, frontal tapes are made of PP film and attached to the front of the diaper with adhesive. Their use has helped to reduce the thickness of the poly film without the risk of potential tears associated with the opening of the lateral tapes from the back sheet. In premium diapers, a special loop system has been developed in order to use Velcro type fasteners (also called the hook and loop system). This loop tape can use a locked loop or a brushed loop in order to provide a softer texture or a stronger grip. 

Polysilicon - Polycrystalline silicon extensively used as conductor/gate materials in a highly doped state. Poly films are typically deposited using high-tem-perature CVD technology. 

Fig. 20.38 Illustration of the electric potential distribution (< ) across the interface between a metal electrode (Me) coated with a neutral polymer (poly) film and an electrolyte solution containing ions that are partitioned into the polymer. El, E2, E3 are three applied electrode potentials at which the polymer is neither oxidized nor reduced. The electrical double layers (1) and (2) correspond to two different bulk concentrations of ions in the polymer, d.p. is the distribution potential.

A great many polymers appear to form films having a flat molecular configuration. Thus various polyesters [7] gave extrapolated areas of about 2.5 m /mg corresponding to about the calculated 60-70 area per segment, or mono-layer Sickness of 3-5 A. A similar behavior was noted for poly(vinyl acetate)... 

While the v-a plots for ionized monolayers often show no distinguishing features, it is entirely possible for such to be present and, in fact, for actual phase transitions to be observed. This was the case for films of poly(4-vinylpyri-dinium) bromide at the air-aqueous electrolyte interface [118]. In addition, electrostatic interactions play a large role in the stabilization of solid-supported lipid monolayers [119] as well as in the interactions between bilayers [120]. 

Lenk T J, Hallmark V M, Rabolt J F, Haussling L and Ringsdorf H 1993 Formation and characterization of self-assembled films of sulphur-derivatized poly(methyl methacrylates) on gold Macromolecules 26 1230-7... 

Silicon is used in many fonns, from high-purity tliin films to bulk material, which may be crystalline, multi- or poly crystalline and amorjDhous (usually hydrogenated). Silicon is the material discussed tire most in tliis article. Substitutional B and P are tire most common (of many) shallow acceptors and donors, respectively. 

Polyethylene films as packaging ma terial plastic squeeze bottles are molded from high density poly ethylene... 

Solid-phase microextractions also have been developed. In one approach, a fused silica fiber is placed inside a syringe needle. The fiber, which is coated with a thin organic film, such as poly(dimethyl siloxane), is lowered into the sample by depressing a plunger and exposed to the sample for a predetermined time. The fiber is then withdrawn into the needle and transferred to a gas chromatograph for analysis. 

The ethylene glycol liberated by reaction (5.L) is removed by lowering the pressure or purging with an inert gas. Because the ethylene glycol produced by reaction (5.L) is removed, proper stoichiometry is assured by proceeding via the intermediate, bis(2-hydroxyethyl) terephthalate otherwise the excess glycol used initially would have a deleterious effect on the degree of polymerization. Poly(ethylene terephthalate) is more familiar by some of its trade names Mylar as a film and Dacron, Kodel, or Terylene as fibers it is also known by the acronym PET. 

PVF film for pLUORJNE CO POUNDS, ORGANIC - POLY(VINYL FLUORIDE)] (Vol 11) Greenhouse warming potential (GWP)... 

Materials that typify thermoresponsive behavior are polyethylene—poly (ethylene glycol) copolymers that are used to functionalize the surfaces of polyethylene films (smart surfaces) (20). When the copolymer is immersed in water, the poly(ethylene glycol) functionaUties at the surfaces have solvation behavior similar to poly(ethylene glycol) itself. The abiUty to design a smart surface in these cases is based on the observed behavior of inverse temperature-dependent solubiUty of poly(alkene oxide)s in water. The behavior is used to produce surface-modified polymers that reversibly change their hydrophilicity and solvation with changes in temperatures. Similar behaviors have been observed as a function of changes in pH (21—24). 

Another widely used overlay adhesive is the contact type. These specialized adhesives, in the same group as mbber cement, may be of the solvent-base or water-base types. They are often used to bond overlays such as wood veneer, vinyl (poly(vinyl chloride)) films, or high pressure laminates such as countertop overlays. 

The majority of xylenes, which are mostly produced by catalytic reforming or petroleum fractions, ate used in motor gasoline (see Gasoline and other MOTORFUELs). The majority of the xylenes that are recovered for petrochemicals use are used to produce PX and OX. PX is the most important commercial isomer. Almost all of the PX is converted to terephthaUc acid and dimethylterephthalate, and then to poly(ethylene terephthalate) for ultimate use in fibers, films, and resins. 

VDP Polyimides. Polyimide films have also been prepared by a kind of VDP (16). The poly(amic acid) layer is first formed by the coevaporation and condensation of two monomers, followed by copolymerization on the substrate. The imidization is carried out in a separate baking step (see POLYIMIDES). 

Acrylics. Acetone is converted via the intermediate acetone cyanohydrin to the monomer methyl methacrylate (MMA) [80-62-6]. The MMA is polymerized to poly(methyl methacrylate) (PMMA) to make the familiar clear acryUc sheet. PMMA is also used in mol ding and extmsion powders. Hydrolysis of acetone cyanohydrin gives methacrylic acid (MAA), a monomer which goes direcdy into acryUc latexes, carboxylated styrene—butadiene polymers, or ethylene—MAA ionomers. As part of the methacrylic stmcture, acetone is found in the following major end use products acryUc sheet mol ding resins, impact modifiers and processing aids, acryUc film, ABS and polyester resin modifiers, surface coatings, acryUc lacquers, emulsion polymers, petroleum chemicals, and various copolymers (see METHACRYLIC ACID AND DERIVATIVES METHACRYLIC POLYMERS). 

Dry chlorine has a great affinity for absorbing moisture, and wet chlorine is extremely corrosive, attacking most common materials except HasteUoy C, titanium, and tantalum. These metals are protected from attack by the acids formed by chlorine hydrolysis because of surface oxide films on the metal. Tantalum is the preferred constmction material for service with wet and dry chlorine. Wet chlorine gas is handled under pressure using fiberglass-reinforced plastics. Rubber-lined steel is suitable for wet chlorine gas handling up to 100°C. At low pressures and low temperatures PVC, chlorinated PVC, and reinforced polyester resins are also used. Polytetrafluoroethylene (PTFE), poly(vinyhdene fluoride) (PVDE), and... 

Polymer Ferroelectrics. In 1969, it was found that strong piezoelectric effects could be induced in the polymer poly(vinyhdene fluoride) (known as PVD2 or PVDF) by apphcation of an electric field (103). Pyroelectricity, with pyroelectric figures of merit comparable to crystalline pyroelectric detectors (104,105) of PVF2 films polarized this way, was discovered two year later (106.)... 

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