Metal-polymer interface formation

Examples. Combined experimental—theoretical studies lead to information at a level not easily obtainable from either approach separately15. Several detailed examples are provided in chapter 7 to illustrate this point, and to provide the basis for the conclusions drawn on relevant polymer surfaces and the early stages of metal-polymer interface formation. This portion of the book is for the reader who wants to become familiar with details upon which certain conclusions, in the final chapter, have been drawn. 

In Situ Study of the Metal-Polymer Interface Formation by Static SIMS Cases of Al and Cu on PET... 

In the present paper. Static Secondary Ion Mass Spectrometry (SSIMS) is used to investigate the interfacial chemistry between vacuum-deposited Al and Cu on PET by following the initial stages of metallization in the submonolayer and monolayer regimes. From the SIMS intensity variations with the deposited metal flux, information on the initial growth mechanisms of the metal layer Is expected. Two metals, copper and aluminum, have been chosen In order to investigate the influence of the metal reactivity on the metal-polymer interface formation. Aluminum with its electropositive sp band is known to react strongly with the carbonyl functionalities of the whereas copper is an inert metal and its Interaction is believed to be much weaker. ... 

In the many reports on photoelectron spectroscopy, studies on the interface formation between PPVs and metals, focus mainly on the two most commonly used top electrode metals in polymer light emitting device structures, namely aluminum [55-62] and calcium [62-67]. Other metals studied include chromium [55, 68], gold [69], nickel [69], sodium [70, 71], and rubidium [72], For the cases of nickel, gold, and chromium deposited on top of the polymer surfaces, interactions with the polymers are reported [55, 68]. In the case of the interface between PPV on top of metallic chromium, however, no interaction with the polymer was detected [55]. The results concerning the interaction between chromium and PPV indicates two different effects, namely the polymer-on-metal versus the metal-on-polymer interface formation. Next, the PPV interface formation with aluminum and calcium will be discussed in more detail. 

The application we have in mind for the metal-polymer interfaces discussed in this book is primarily that where the polymer serves as the electroactive material (semiconductor) in an electronic device and the metal is the electric contact to the device. Metal-semiconductor interfaces, in general, have been the subject of intensive studies since the pioneering work of Schottky, Stromer and Waibel1, who were the first to explain the mechanisms behind the rectifying behaviour in this type of asymmetric electric contact. Today, there still occur developments in the understanding of the basic physics of the barrier formation at the interface, and a complete understanding of all the factors that determine the height of the (Schottky) barrier is still ahead of us2. 

Fig. 24 Principal corrosion model explaining the formation of a galvanic element in case of cathodic delamination on polymer-coated iron, (a) Cross section through a metal-polymer interface with a defect in the polymer coating (b) overview of the polarization curves at the defect (i), the intact interface fii) and the situation after galvanic coupling of the parts (c).

Two principle mechanisms that are discussed as possible corrosion protection mechanisms on mild steel are discussed in short. ICPs may induce the formation of a passive oxide [206]. The ICP will be reduced as a consequence of passivation and will be reoxidized by oxygen reduction. Consequently, the ICP may promote the cathodic oxygen reduction on the polymer surface rather than at the metal-polymer interface. On the basis of the good corrosion results gained by the combination of a molecular adhesion promoter and the subsequent electrodeposition of the polymethylthiophene film Rammelt and coworkers [207] concluded that the essential aspect of the corrosion protection by ICPs could be the local separation of iron oxidation and oxygen reduction. This would eliminate the local pH increase at the metal surface and subsequent cathodic disbondment. 

This paper aims to give a brief review of our present understanding of metal diffusion during polymer metallization and of the implications for the formation and structure of metal-polymer interfaces. For recent more extended reviews the reader is also referred to references 2-4. 

Particularly, the formation of new chemical bonds at a metal-polymer interface has recently gained a lot of attention, thanks to development of surface analytical tools. In this connection, photoemission spectroscopies (XPS, UPS) have been extensively used. The adhesion is related to bond formation between the metal atom and the functional groups at the polymer surface. The presence of oxygen containing groups is found to lead to the formation of metal-oxygen-polymer complexes and to increase the adhesion. ... 

A study on meta]-polymer interface formation following an in situ plasma treatment is presented. The plasma treatment is performed in a dual firequency ECR plasma This enables to control some of the main plasma parameters The study is focused on a model system consisting of a polypropylene substrate and a magnesium metal overlayer. Due to large variations in the interface properties depending on the surface treatment, this system allows deeper insight in the interface formation. 

In this contribution, we report on the surface modifications of polymers by a dual frequency electron cyclotron resonance (ECR) plasma and their influence on the formation of the metal-polymer interfaces. The surface modifications are studied with respect to different parameters of the plasma treatment including the influence of an atmospheric contact. The interface of an evaporated metal film with a polymer surface is characterized in terms of the observed growth mode of the film as a function of the polymer surface properties. 

Figure 5. Ener level shematics at the metal/polymer interface. The formation of bipolaron lattice at the interface depends on the relative positions of the metal Fermi level and the bipolarons. At the interface, Ca will tend to form negative bipolarons (a), A1 will not form bipolarons (b) and Au will tend to form positive bipolarons (c). Although bipolarons extend over several monomeric units, they span only 4 units in this diagram (33). We iUustrated the bipolarons with PPV chains.

Glass fibers sized with polyurethane and polyvinyl acetate formed different interfaces. This was due to the differences in reactivity and miscibility. Polyurethane forms a stronger interface because it is reactive and miscible with epoxy resin. " Surface tension of glass surface in a molten state correlates with the interface formation with polymer. The diffusion at interface contributes to a complex structure controlling properties of the interphase. The analysis of the diffusion at the interphase has helped to develop an understanding of the formation of metal-polymer interfaces and plastic welding. 

Clustering of water at the metal-polymer interface and the subsequent formation of an electrochemical double layer can occur only if the adhesion between metal and coating is weaker than the bond between metal and water or pol5mier and water. For a proper evaluation, however, a distinction must be made between wet adhesion and osmotic blistering. 

R.I. Burger, L.J. Gerenser, Understanding the formation and properties of metal/ polymer interfaces via spectroscopic studies of chemical bonding, in Proceedings of the 34th Annual Technical Conference, Society of Vacuum Coaters, 1991, p. 162. 

Quantum chemical calculations, 172 Quantum chemical method, calculations of the adsorption of water by, 172 Quantum mechanical calculations for the metal-solution interface (Kripsonsov), 174 and water adsorption, 76 Quartz crystal micro-balance, used for electronically conducting polymer formation, 578... 

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