This study describes a novel method for fabricating the plastic mold with microstructure by nanofiber imprinting (NFI) into Si form. The nanofiber was produced by electro-spinning (ES) process which provides a simple and versatile method for generating ultrathin fibers using variety of materials. The effects of ES condition on the diameter of nanofiber were investigated for optimizing to generate ultrafine fiber. By melting ES-nanofiber coated on Si forms that have various micro-structures including line and space pattern, multi-pillars and holes, the plastic molds with those micro-structures were replicated for polymethylmethacrylate (PMMA) polymer. The effect of aspect ratio in microstructure on the shape transcription was investigated by changing Si form from 1μm to 50μm in width for 10μm in height. The usefulness of ES-NFI method proposed in this study was also investigated by comparing with a conventional dipping method. The experimental result shown that the microstructures with 1μm wide to 10μm high could be formed precisely on the surface of plastic mold after melting ES-nanofiber with approx 100nm in mean diameter. It was shown that ES-NFI method was superior for fabricating the plastic mold with finer microstructures.This conclusion does not only attribute a good transcription to finer fiber, but it is considered to be obtained by in-situ extraction of solvent during ES process.

This study aims to develop an eco-friendly fabrication method for micro-structured parts with high aspect ratio. To achieve this purpose, nanopowder printing (nPP) process was adopted to the plastic mold with microstructures produced by electrospinning nanofiber imprinting (ES-NFI) method. A novel method named as ES-NFI sacrificial plastic mold nanopowder printing (ES-NFI/nPP) was proposed and demonstrated in this study. Micro plastic molds were prepared by ES-NFI method using Si forms that have various micro-structures including line and space (L/S) pattern, multi-pillars and holes. The effects of aspect ratio in microstructure on the shape transcription were investigated by changing Si forms from 1μm to 50μm wide for 10μm high. Also the composition of paste materials made from TiO2 nano-sized powder and PEG water-soluble binder was varied for the optimization. It was shown from the experimental results that the sintered part with microstructures of 50μm wide for 10μm high could be formed soundly, and it was also desirable to use the paste materials with lower content of binder polymer in keeping adequate viscosity. It was confirmed that ES-NFI/nPP method was a useful method for fabricating the micro-structured parts in the mass production.

No abstract

No abstract