Polymer metal interaction

This general area has been reviewed in depth by Briggs (1990), who gives an extended bibliography of the application of XPS to a number of aspects, including plasma treatment, photooxidation and weathering, biomedical polymers and polymer-metal interactions. 

Photoelectron Spectroscopies Applied to Polymer—Metal Interactions... 

With ultra violet sources (He I) the entire valence band could not be obtained (29,58). Interestingly, the two polyimides, PMDA-ODA and BPDA-PDA which showed such distinctly different core-level spectra (Figure 6) show quite similar valence-band spectra (Figure 11) with only subtle differences. Figure 12 and Figure 13 show the cross-section modulation for polyamic acid on Cu and Cr. Detailed analysis of these spectra will lead to further understanding of the polymer-metal interaction. 

This paper will discuss the use of Near-Edge X-ray Absorption Fine Structure (NEXAFS) Spectroscopy to study the unoccupied n molecular orbital (MO) structures of polymers and polymer-metal interfaces. A collection of systematic NEXAFS and EELS studies of simple organic compounds by J. Stohr and others (1-10) has led to recent advances in the understanding and interpretation of this technique. It s application to complicated polymers and polymer-metal interactions has only begun, but NEXAFS spectroscopy promises to be an important complement to other photoelectron spectroscopies. 

Based on these observations, the distinction between water penetration and salt intrusion may be schematically represented as shown in Figures 24.14 and 24.15. In these figures, two interfaces— film/water and film/metal—are involved, and the effect of lack of water-insensitive adhesion at the film/metal interface is also depicted. In the absence of water-insensitive adhesion, water molecules that reach the polymer/ metal interface cluster together by breaking weak polymer metal interaction. If one... 

In BPDA-PDA, the only hydrolysis observed was of anhydride. If the samples are cured to at least 400 °C to minimize the residual anhydride, the bulk polymer should be quite stable to hydrolysis. In this material, then, the major remaining concerns about hydrolytic stability center on the polymer-substrate interfaces whether possible polymer-metal interactions could result in the formation of hydrolytically unstable products and whether or not agents used to promote adhesion will retain their efficacy under humid aging. 

Buckley, D.H. Brainard, W.A."The Atomic Nature of Polymer-Metal Interactions in Adhesion, Friction and Wear," Advance in Polymer Friction and Wear, edited by Lee, L.H. Polymer Science and Technology, Volume 5A, Plenum Press, New York (1974). 

Polymer-Metal Interaction in Adhesion, Friction and Wear",... 

The technique of choice for studying thin films on metals (or certain other substrates) directly is single reflection RAIR [47-54]. The limitation here is that the substrate must be very smooth, but this can be easily achieved by polishing the metal before deposition of the film. Characterizations of thin organic layers on metal (oxide) surfaces, such as occur in lubricants, corrosion inhibitors, adhesives, polymers, paints, and so forth, are specific applications of this rather recent form of FTIR. It should be noted that the relative band positions and shapes may be different in this technique than in conventional transmission IR. The spectrum may also change with the thickness of the organic film, which implies that polymer/metal interactions are in principle observed [47,51]. The teehnique is so surface sensitive that oxidation of metals can be determined in situ [51] and the packing... 

M. W. Conway, S. W. Almond, and S. H. Shah, Polymer-Metal Interactions and Their Influence on Gel Performance in Fracturing Service, Polym. Mater. Sci. Eng., 51 7 (1984). 

Another approach to the deposition of nanometre-sized particles on a surface has been described by Roth el a/. who thermally evaporated gold onto polystyrene in a vacuum chamber to form a thin film. Since the polymer-metal interaction is much weaker than the metal-metal interaction, the gold atoms form clusters in a self-assembly process. The gradient in cluster density was induced by using a blocking mask to shadow parts of the substrate. 

The Atomic Nature of Polymer-Metal Interactions in Adhesion, Friction, and Wear... 

The polymers PTFE (polytetraf1uoro-ethylene) and polyimide were studied contacting various metals in adhesion and sliding friction experiments. Field ion microscopy and Auger emission spectroscopy, were used to examine the nature of the polymer-metal interactions. Strong adhesion of polymers to all metals in both the clean and oxidized states was observed. 

Another type of polymer-metal interaction that has been observed is associated with the formation of polymeric surface films from the interaction of monomers or (lower molecular weight species) with metal surfaces in sliding contact. Frictional energy provides the activation energy for polymerization. This phenomenon was first observed in electrical contacts >. And more recently it has been observed in friction and wear studies . ... 

---