Multilayered film materials

Single-layer inhibited films can neither present a insurmountable barrier to diffusive permeation of corrosion-active agents from the outside, nor they can avert infiltration and condensation of water vapor on the metal surface, but are able to hamper the removal of ion products from the zone of electrochemical reactions. The corrosion protection barrier factor is drastically improved in multilayered film materials. 

Film or sheet generally function as supports for other materials, as barriers or covers such as packaging, as insulation, or as materials of constmction. The uses depend on the unique combination of properties of the specific resins or plastic materials chosen. When multilayer films or sheets are made, the product properties can be varied to meet almost any need. Further modification of properties can be achieved by use of such additives or modifiers as plasticizers (qv), antistatic agents (qv), fire retardants, sHp agents, uv and thermal stabilizers, dyes (qv) or pigments (qv), and biodegradable activators. 

Melt Extrusion. By far the most important method for producing film and sheeting materials reties on one or another of the various melt extmsion techniques (5). The main variations of melt extmsion are the slot (or flat) die-cast film process, the blown films process, and the flat die sheeting-stack process. These may be combined with one or more steps such as coextmsion wherein multilayer film or sheet is formed, biaxial orientation, and in-line coating (6). 

Fabrication. Flexible packaging materials may be mono- or multilayer. Monolayer materials are usually films that have been produced by polymer resin melting and extmsion. 

Free mono- and multilayer films may be adhesive- or extmsion-bonded in the laminating process. The bonding adhesive may be water- or solvent-based. Alternatively, a temperature-dependent polymer-based adhesive without solvent may be heated and set by cooling. In extmsion lamination, a film of a thermoplastic such as polyethylene is extmded as a bond between the two flat materials, which are brought together between a chilled and backup roU. 

Antireflective (AR) coatings are required on optics to reduce the reflective surface losses. Vitreous siHca coatings in the form of porous or multilayer films are used extensively in this appHcation. Antireflective coatings have been developed which employ coUoidal fused siHca sol—gel particles made from organometaUic materials (253). 

In conclusion, one should choose an appropriate multilayer system for different application purposes. For the case of fatigue wear, multilayer films consisting of two hard materials with different shear modulus, such as DLCAVC multilayer film [115], would satisfy the requirement for wear resistance. While for abrasive wear, multilayer films consisting of hard ceramic layers and soft metal layers, such as TiN/Ti and CrN/Cr [116,117] multilayer films are more competent. 

For industrial products, such as films and fibers (woven and un-woven), the concept development stage is shown in Fig. 10.3-2. Under materials development, searches are carried out for chemicals and chemical mixtures having the desired properties and performance, and reaction paths for chemical synthesis. Under product/process technology development, often new methods are needed for example, methods for creating multilayer films. And, finally, under manufacturing process development, an example of something new would be multilayer dies for producing multilayer polymer films. 

The multilayer film of the optical core produces a green reflector. The visual effects of the green reflector are not easily reproduced, yielding the easily identified security feature. Possible raw materials are polystyrene (PS), and polymethylmethacrylate (PMMA). There is a substantial difference in refractive... 

Li, Z., et al., Electrostatic layer-by-layer self-assembly multilayer films based on graphene and manganese dioxide sheets as novel electrode materials for supercapacitors. Journal of Materials Chemistry, 2011. 21(10) p. 3397-3403. 

A detailed transport model for resist dissolution has been developed (169). In conjunction with standard ellipsometric equations describing multilayer films, the model provides quantitative agreement with the observed traces from the in situ ellipsometer. Model parameters are thus extracted, and their significance in terms of molecular structures of the system can be established. This model can then be extended for predictive purposes in the design and selection of resist materials. 

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