Multilayered anticorrosion films

PS is limited in its use and is mostly applied as a film-forming material because of its brittleness, insufEciently high heat resistance and instability in organic solvents. To improve its impact resistance and elasticity PS is often modified by rubbers [20,22]. Foamed impact-resistant PS is rather seldom used as a layer-vessel incorporating Cl in multilayered anticorrosion films. 

This broad spectrum of properties of multilayered anticorrosion films is used either as the base, a Cl carrier or adhesive (if required) because of numerous possible combinations of polymer materials. 

Films with Cl in the gaseous phase represent either multilayered or combined materials in macro- (Fig. 2.3f) or microcavities (Fig. 2.3g) where the volatile anticorrosion agents are sealed. 

Thin solid films are layers that are present on a surface and have their top interface exposed to the environment Their extreme thinness in comparison with their lateral dimensions makes them systems that are infinite in two dimensions and are confined between an infinite gaseous phase and an infinite solid phase in the third one. As a result the global property of a layer is a combination of bulk and interface properties thus, one has to take into accoimt the thickness of the layer and the nature of the substrate when designing a coating for a specific application. Thin layers can be used for various purposes, depending on their surfece and/or bulk intrinsic properties. They can be dense, porous, patterned, multilayered, composite, and so on. Sol-gel films can be found in many different application domains such as optics (e.g., antireflection, self-cleaning, smart windows, and conductive transparent layers), electronics (e.g., microfabrication, low-/ , and self-assembled monolayers (SAMs)), protection (e.g., anticorrosion, anti-abrasion, and antistatic), and analysis (e.g., selective sensors). In most of these applications, the function must be identical on the whole surface of the substrate, and thus the thickness has to be controlled as much as possible and must be as uniform as possible. 

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