Self-assembly of fine particles along tool-mark produced by free-form cutting for improving biochemical analysis

—Wettability modification with controlled cutting conditions—

抄録

Self-assembly of fine particles on three-dimensional structure enables a lot of applications. Dip-coating is one of the processes to produce such assemblies and often utilized because of high productivity and simplicity, just drawing up from suspension in which particles are dispersed. However, it has been applied only to planar substrates because the spreading profile of suspension is constant when the drawing up speed is constant while that on three-dimensional substrates becomes complex. This study aims to realize uniform assembly on the three-dimensional structure with the texture fabricated using a five-axis milling machine. First, the spreading profile of water on directionally slanted grooves on planar substrate was investigated. It was found that water is well held by pinning and the effect becomes highest when the slant angle 30°. It was also found that the coverage increased when the groove pitch 100μm and the drawing up speed 12.5mm/s. Then, assembly on the three-dimensional profile was tried. Dip-coating process was carried out referring the appropriate conditions for planar substrates. The effectiveness of the texture was verified comparing the assembly results on parabolic surface with/without it. Finally, it was found the uniform assembly on parabolic surface is applicable to optical element.