以靜止流微影術製造具有磁性之玻璃微元件

Abstract

微型化是近幾年來熱門的研究課題，然而如何低成本、高效率地生產微型元件，並兼顧其機械強度與可操控性則是一大瓶頸。本研究以溶膠凝膠(Sol-gel)製程結合靜止流體微影術(Stop-Flow Lithography)可大量製造高強度且帶有磁性之玻璃齒輪。我們在以PDMS製作之微流道中以光刻技術(Photolithography)聚合成高分子齒輪顆粒，在其前驅物溶液中含有高分子單體聚乙二醇二丙烯酸(PEGDA 700)、二氧化矽前驅物正矽酸乙酯(TEOS)，且以甲基丙烯酰氧丙基三甲氧基矽烷(MEMO)連結高分子主體結構及二氧化矽前驅物，並加入四氧化三鐵超順磁性微米顆粒(Fe3O4)作為磁性來源。待光聚合反應完成後將高分子顆粒加熱，使TEOS進行熱縮合反應(Thermal condensation)。待縮合反應後使高分子齒輪顆粒於不同溫度(350℃、500℃及1150℃)下進行燒結程序並使高分子降解，發現皆可得到高機械強度之玻璃微齒輪。並測量觀察在各條件下其表面結構與機械性質變化，並確認在各燒結條件下仍可以保留其磁性，並能以外部磁場加以驅動使齒輪轉動。高機械強度之齒輪元件為組裝微型機械之基本條件，而可加以操縱驅動之玻璃微齒輪能夠作為微型機械之動力源，對於微型機械之發展將是一大助力。

In recent years, microelectromechanical system has attracted much attention in engineering society. With miniaturization, we could not only reduce the cost of many existing applications but also have many possibilities for developing new applications. However, the mass production of microcomponents for micromachinery is always an issue. In this study, we synthesized magnetic glass microgears by using the stop-flow lithography and sol-gel process. The microgears with complex shape were polymerized in a PDMS microchannel by photolithography. The prepolymer solution consisted of tetraethyl orthosilicate(TEOS) as the precursor of silicon-dioxide, poly(ethylene glycol) diacrylate (PEGDA 700) as the monomer, Darocur 1173 as the photoinitiator, 3-(Trimethoxysilyl)propyl methacrylate(MEMO) as the bridge monomer and magnetic particles as the source of the magnetism. The polymerized particles were then sintered to generate the glass microgears. These heating steps allowed polymer to burn out and TEOS would condense to SiO2. The resulting microgears were found to have great mechanical strength and can be controlled remotely by an external magnetic field. With these special features, we expect that the magnetic glass microgears have great potential to be used in the applications of micromachines in the future.