Film/coating formation nucleation

These conducting polymers are sometimes termed organic metals, and their formation as thin-film coatings on an electrode involves nucleation phenomena so perhaps by analogy with metal electrodeposition under ultrasound there have been studies to improve the quality of the deposited materials. Polypyrrole readily forms acceptable films under a wide variety of conditions [174], although there are subtle distinctions in behavior as a result of exact preparation procedure [175], Ultrasound from 38 or 500 kHz baths does not appear to appreciably improve polypyrrole film formation, at least from MeCN electrolyte at the normal current density of 1 mAmp... 

J. A. Baglio, B. C. Farnsworth, S. Hankin, C. Sung, J. Hefter, and M. Tabasky, Studies on the formation of diamond nucleation sites on <100> silicon substrates, in Diamond and Diamond-like Films and Coatings, (R. E. Clausing, L. L. Horton,... 

The creation of 2D crystals of both micron sized and nanometre sized particles remains a somewhat empirical process due to the ill-defined role of the substrate or surface on which nucleation takes place. Perrin first observed diffusion and ordering of micron sized gamboge 2D crystals in 1909 under an optical microscope [32]. Several techniques have been proposed for the formation of 2D arrays at either solid-liquid surfaces or at the air-water interface. Pieranski [33], Murray and van Winkle [34] and later Micheletto et al. [14] have simply evaporated latex dispersions. Dimitrov and coworkers used a dip-coating procedure, which can produce continuous 2D arrays [35,36]. The method involves the adsorption of particles from the bulk solution at the tricontact phase line. Evaporation of the thin water film leads to an attractive surface capillary force which aids condensation into an ordered structure. By withdrawing the film at the same rate as deposition is occurring, a continuous film of monolayered particles is created. Since the rate of deposition is measured with a CCD camera, it is not possible to use nanometer sized particles with this method, unless a nonoptical monitor for the deposition process can be found. 

While the dominant substrate for low pressure growth of diamond films is single crystal silicon, several different materials such as Ta, Mo, W, Cu, Au, Ni, SiC, Si02, and Si3N4 have been coated with polycrystalline diamond or diamond-like deposits. The nucleation rates and the adhesion of the generated films vary with the type of substrate material, which is related to the formation of intermediate carbide layers such as SiC or WC. 

J. H. Wei, D. C. Coffey, D. S. Ginger, Nucleating pattern formation in spin-coated polymer blend films with nanoscale surface templates. J. Phys. Chem. B, 2006, no, 24324. 

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