| Summary: | 碩士 === 國立成功大學 === 機械工程學系 === 102 === Lab on a chip (LOC) was mainly used in the simplification of biomedical detection step, and separation is one of the indispensable pretreatment during the detection process. In this study a combination channel of spiral and backward facing step patterns were designed to optimize the separation function without any extra power like electric or magnetic field. The foil-assisted CO2 laser method was used to process spiral microfluidic chip with PMMA (Polymethylmethacrylate) polymer for the separation of suspended particles.
Although laser ablation was widely used due to its cheap and convenient characteristic, it generates poor surfaces quality during the ablating process with polymers. In this study, a different types of foil-assisted laser micromachining technique was developed to carry out the improvement of microchannel surfaces quality. The results showed that the bulges height was reduced from 5 to 1.5 μm and the channel width was reduced from 230 to 120μm.
Besides, some polymer microchips had an inherent hydrophobic property, which may affect the flow process during the fluidic experiment. Accordingly, this study proposes a polyethylene glycol (PEG) coating for improving the long-term hydrophilic properties of PDMS substrates for over 420 hours.
To sum up, a costless and time-saving procedure, including microchip fabrication and surface modification, was developed to apply positively in microfluidic separation chip with a combination flow distribution design including spiral dean vortices and backward facing step, which can provide 99% separation efficiency within a certain flow range.
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