Chemical vapor deposition concentration gradients

The polymer-metal interface shown in Fig. was derived from an electron micrograph obtained by Mazur and Reich.They electrodeposited silver from a silver ion solution diffusing through a polyimide film. Particles not connected to the diffusion source were removed by computer analysis. The deposited silver particles essentially "decorate the concentration profile and permit the diffusion front to be observed. A 1000-A thin slice was used to aproximate two dimensional diffusion. The fractal dimension of this interface was determined by computer analysis to be approximately 1.7. Similar ramified interface fronts are created by vapor deposition of metal atoms on polymers and by certain ion bombardment treatments of polymer surfaces. The fractal front is fairly insensitive to the details of the concentration profile. However, strong chemical potential gradients in asymmetric interfaces may promote a more planar, less ramified structure. The fractal characteristics of polymer interfaces... 

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