It could be shown that by a simple casting process from solution two-dimensionally ordered arrays of mesoscopic (i.e., in the range of submicrometer to micrometer) polymer aggregates on solid substrates can be formed. Patterns were investigated by optical microscopy and atomic force microscopy. The pattern formation was observed in situ by optical and fluorescence microscopy and it was found that a "fingering instability" at the three-phase-line of a solution droplet is the crucial process for pattern formation. (c) 1999 American Institute of Physics.

Hydrogen gas production during corrosion of copper by water Hultquist, G.; Graham, M. J.; Szakalos, P.; Sproule, G.I.; Rosengren, A.; Gråsjö, L.Contact us / Contactez nous: nparc.cisti@nrc-cnrc.gc.ca.

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According to a current concept, copper canisters of thickness 0.05 m will be safe for nuclear waste containment for 100,000 years. We show that more than 1 m copper thickness might be required for 100,000 years durability based on water exposures of copper for 20 h, 7 weeks, 15 years, and 333 years. An observed evolution of hydrogen which involves heterogeneous catalysis of molecular hydrogen, first principles simulations, thermodynamic considerations and corrosion product characterization provide further evidence that water corrodes copper resulting in the formation of a copper hydroxide. These findings cast additional doubt on copper for nuclear waste containment and other important applications.

Mesoscopic two-dimensional patterns, regular dots, stripes, and honeycomb networks are formed when dilute organic solutions of polymers are cast on solid surfaces. Dynamic patterns, so-called "dissipative structures", formed in the non-equilibrium thermodynamic process of solvent evaporation, are fixed as the two-dimensional polymer patterns on substrates. Some photonic and electronic applications of the mesoscopic polymer patterns are described in this article.