Research On Hot Embossing And Bonding For Fabrication Of Plastic Microfluidic Chips

The Microfluidic Chips is the main research orientation of Miniaturized Total Analysis Syatem (uTAS). It's widely application in the field of life sciences, iatrology, new drugs exploitation, chemistry, foodstuff and environment inspecting etc. Polymers represent certain advantages such as process simple, normally low cost and esay to high volume production. In this dissertation, hot embossing and bonding techniques were researched for fabrication plastic Microfluidic Chips. The drug was detected on the Microfluidic Chips produced by this method.In hot embossing polymers microchannels, the material was processed near the glass transition temperature. The viso-elastic behaviors of material are studied by parallel model combined with spring and viscous dashpots. It's found that polymer's mechanical properties behave strongly in time and temperature dependent manner.After discussing flow behaviors of polymers near the glass transition temperature, the mathematical model of heat transmission through thermal medium and the mathematical model of pressure distribution within polymer were studied. This finding indicates that a non-uniform pressure distribution in the radius direction produced by embossing processl. However, a higher embossing pressure during cooling leads to a more uniform shrinkage in the elastically deformed. And thus reduces the variation of microchannel.Experiment on hot embossing microchannels was carried out. Embossing parameters temperature, embossing force and time governing hot embossing were investigated. An experiment method was put forward to establish PMMA microchannels' hot embossing process. In this process, the replication rate of microchannels is high, and microchannels within 5% variance are obtained. This method gives guidance to establish hot embossing process of materials from different source.A substrate with microchannels is bonded with a cover to form close channels. The pretreatment process of PMMA surface before bonding was discussed. The Microfuidic Chips was bonded by thermal bonding method. Its bonding intensity is higher than 0.1 Mpa. The electro-osmotic flow is 2.8x10-4cm-2V-1s-1, and voltage-ampere curves of PMMA microchannel in 20nmol/L buffer solution of borax were tested too. The performance of the PMMA chips is demonstrated in the electrophoretic separation of methamphetamine from byproducts with a precision of 4.4% RSD (n=6) and an efficiency of 11.4x104m-1'. In addition, adhesive bondingmethod was tried out to bond the plastic Microfluidic Chips, and the bonding intensity is higher than that of thermal bonding method.