Side metal/polymer interfaces

The reactions of various chemicals with the metal/polymer bond were examined utilizing samples of 125 pm thick polyetherimide film which had been metallized on only one side. Traces, 3.2 mm wide, were created similarly to those employed for peel test measurements. The fibn is translucent and thus the degree to which the metal/polymer interface was altered could be viewed dirough the back (dorsal side) of the substrate. The normal appearance of the metal/polyetherimide interface, after heat treatment, is bronze. A color change from bronze to pink was observed at the interface when reactions between the... 

Additional evidence of oxygen being involved as pait of the metal polymer link was obtained by examining the thiclmess of the metal oxide layer on the outer surface of the metal and at the metal/polymer interface prior to and subsequent to the heat-tieatment step. Analysis of the backside of the intetphase region was accomplished via dissolution of the polymer substrate The data in Table VI show that the oxide thicknesses were nominally equal at the air and polymer sides of the structure. The oxide thicknesses were independent of metal deposition technique although the presence of the palladium catalyst employed for electroless deposition complicated the analyses. X-ray photoelectron spectroscopy identified the oxide species as cuprous oxide 10,17. Excellent adhesion was obtained once the oxide thickness exceeded 3 nm at the metal/polyetherimide interfacial zone. 

If the left side of Eq. (7-103) is regarded as the half-cell potential of the metal/polymer interface, then according to Eqs. (7-87) and (7-88)... 

As shown above, the typical redox polymer contains an appreciable density of mobile ionic species. Thus, the ionic conductivity of the polymer phase is rather high. An electrical double layer can form at the metal/polymer interface, i.e., the electric potential drops sharply at the polymer side of the interface (see Fig. 20.38). Consequently, the polymer-bound redox sites that contact the metal electrode surface may be oxidized/reduced by a conventional electrochemical mechanism. 

No Cr or Cu is detected at any of the fracture surfaces except for the one annealed at 350°C. Here, Cr (52 amu) and Cu (63 and 65 amu) are both detected at the two sides of the interface. This must be interpreted as a diffusion of both metals into the polymer, as has been amply documented (17). The ions detected at 63/65 amu at the fractures surfaces of the samples annealed at lower temperatures are hydrocarbon ions, since they do not appear in the characteristic isotopic ratio of Cu ions. 

Fig. 3. The ramified fractal nature of diffuse interfaces is shown for (top) a computer simulated 2-d monomer-monomer interface where the heavy region represents the connected monomers on one side, (middle) a simulated 2-d random coil polymer interface at the reptation time, and (bottom) electrochemically deposited Silver diffusing in polyimide with the unconnected metal atoms removed to show the fractal diffusion front of the connected metal atoms. (Wool and Long)...

Overall, the polymer of tomorrow will reach into inorganic, quasi metallic combinations on one side, and bio polymers of living tissue on the other. These will provide the widest interface in the science and the technology of matter. Both the wonderful spiral conformation of collagen, Fig. 23, and the subtle information content of its peptide components in muscle action are qualities to be sought in polymers made by people. 

First, satellite structure on the high binding energy side of, for example, an XPS core-level line (or peak ) corresponds to so-called shake-up (referred to below as s.u. ) and shake-ofF2S-29 effects, the former of which is illustrated, by M+, in Fig. 3.1. Shake-off is just shake-up to the continuum rather than to an unoccupied molecular state. Considerations of (1) are important in comparisons with the results of model calculations while (2) is of use as an indication of the electronic transitions in the molecules under study, an example of which is found in studies of the early stages of interface formation, i.e., the interactions of reactive metal atoms with conjugated polymer surfaces. Since use will be made of these effects in subsequent chapters, they are outlined briefly below. 

The spectrum of the polymer side of the control is very similar to that of the untreated PI (Figure 4). No new peaks are observed, which suggests that no major chemical changes have taken place in the interface region. However, the intensities at masses 55 and 91 have decreased somewhat and those at 12, 15, 27, 50/51, 62/63 and of the entire Cj cluster have increased to some extent. These changes indicate an increased unsaturation of the polymer in die interface region (7). The spectrum of the backside of the metal film showed the same trend. 

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