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Manipulation of thin liquid films and nanoparticles with surface charge patterns Type: primarily experimental project, option for numerical calculations Contact: Anton Darhuber (e-mail: a.a.darhuber) We designed a setup that allows writing of arbitrary surface charge patterns onto electrically insulating substrates. A droplet of water is attached to a metallic needle and dragged over the surface with a computer-controlled xy-translation stage. Photograph (left) and schematic (right) of a setup for writing arbitrary surface charge patterns onto an electrically insulating substrate. The non-uniform surface charge distribution induces electrical stresses in thin liquid films that are deposited onto the substrate, which induces flow towards regions of higher surface charge density. The objectives of the project are to study 1) the charge deposition process for a number of different substrate materials, 2) the dynamics of the redistribution of a liquid film that is spin-coated on top of the surface charges as well as 3) the preferred deposition of suspended nanoparticles on the charged or the uncharged regions. (Left) surface charge pattern written onto a plastic substrate. (Right) Photograph of film thickness modulation induced in a ~ 5 micron thin liquid film.