Fabrication and Evaluation Methods of Micro-structured Surfaces for Droplet Impact Experiments

The continuously increasing importance of micro-structured surfaces in technical applications and research require further development and use of reliable manufacturing processes as well as investigation methods for quality assurance. An overview of possible reproduction processes will be given and a new fabrication route in combination of laser lithography and nickel electroplating to provide stable mold inserts is introduced. Three methods for inspecting the reproduction quality of the polymeric micro-structured surfaces are presented discussing the respective advantages and disadvantages as well as the limiting factors diminishing the resolving power. The replication quality of four micro-structured surfaces produced with the hot embossing method is investigated, and the results are compared using these three techniques. Additionally, the principle investigation strategy of a test rig for droplet impact experiments on micro-structured surfaces is going to be outlined. Finally, preliminary results of droplet impacts on a structured surface are shown and discussed.