Consideration on functional surface design by depositing various materials with specific pattern

Abstract

This paper discusses surface functional design by depositing various materials with regular pattern. First, three examples are introduced: (1) Thermal conductivity of pitch-type carbon fiber is higher than those of metals and thus the chopped fibers were deposited with spray coating on a resin plate to increase the overall thermal conductivity along the plate. (2) Silver nanoparticles were deposited and fixed keeping regular spacing, and attainable antibacterial activity was examined to make clear the minimum quantity of expensive silver particles. (3) Silica particles were self-assembled on a silicon wafer configuring lattice pattern to compromise both of optical reflectivity and wettability. It was confirmed that deposited particles shorten the drying time because the pinning hold the droplet edge and thus the surface area large, while reflectivity was kept by the smooth surface between the lattice particles pattern. Spatial frequency of the surface structure was often discussed as well as the material property, because regular cross-sectional profile or texture often changes the surface functionality. Finally, design methodology was discussed. Assuming different functions are related to respective spatial frequency component of the texture or material deposition, and the combination of plural frequency components should be integrated on the surface cross sectional profile to compromise plural functions simultaneously. Case study was the combination of friction, wettability and optical functions.