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We report the assembly and disassembly of conducting microwires, driven by inhomogeneous high frequency electric fields, from a solution of gold colloids. The formation of gold microwires via dielectrophoresis is well known and has been qualitatively investigated but we report for the first time observations of reversible growth arising from changes in the frequency of the applied field. Rapid frequency shifts cause the assembled fractal structures to spontaneously disassemble and reassemble. We have investigated the influence of a range of parameters - including, in particular, the limits and rate of the frequency ramp - on the nucleation and growth of the microwires. We shall discuss the implications of our findings for directed and tuned assembly of nanoscale particles. Special attention is paid to the role of the competing forces present during the observed growth and disassembly. |