Large Area Surface Patterning by Nanoimprinting for Hydrophobic Metallic Surfaces

Leonie Frohnapfel¹, Enrico Bruder¹, Paul Braun¹, Karsten Durst¹

¹ Physikalische Metallkunde, Fachbereich Material- und Geowissenschaften, TU Darmstadt,

  Alarich-Weiss-Str. 2, Darmstadt 64287, Deutschland

E-Mail: leonie.frohnapfel@stud.tu-darmstadt.de

e.bruder@phm.tu-darmstadt.de

p.braun@phm.tu-darmstadt.de

k.durst@phm.tu-darmstadt.de

Since the surface of a material governs its interaction with the environment, a modification and resulting functionalization of the surface is of interest for a variety of applications. One way to alter the surface topography and properties is patterning via mechanical processing (e.g. nanoimprinting).

In the present work, nanoimprinting is used to functionalize metallic surfaces by modifying the wetting behavior of nanocrystalline brass (nc CuZn30) and cold worked austenitic steel (cw AISI 316). A nanostructured die with cross and line like periodic pattern with periodicities in the micrometer regime was pressed into the sample material and the flow behavior in dependence of the applied contact pressure has been investigated using SEM and confocal laser scanning microscopy. The plastic flow during contact with single asperities of the punch thereby resembles the flow during flat punch nanoindentation and is influenced by the grain size and mechanical behavior of the substrate materials. There, a correlation between microstructural effects on the flow behavior of nc CuZn30 and cw AISI 316 could be observed. To validate a possible change in surface properties, contact angle measurements have been carried out over an aging period of 30 days. Thus, the contribution of the structure itself and additional chemical effects could be investigated for both sample materials.