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Reversible Pattern Formation through Photolysis

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posted on 15.08.2006 by Timothy R. Kline, Ayusman Sen
We report a photolytic method to induce spatial and temporal patterning/deposition of particles at the micron scale on a time scale of seconds. Reversible pattern formation by negatively charged particles occur around micron-sized silver features on different substrates when exposed to UV light in the presence of aqueous hydrogen peroxide. Diffusiophoretic motion due to a spatially defined ion gradient accounts for our observations. Atomic force and optical microscopy, as well as conductivity measurements, support this hypothesis.