Studies On The Fabrication Technology Of PDMS Microfluidic Chips

In order to prepare well-performed microfluidic chips, researches were carried out on the polydimethylsiloxane (PDMS) microchannel molding process,the surface modification process and chip bonding process. The main research work and results are as follows:The two-step molding technology, which included the formation technology of glass microchannel template, the molding of PDMS raised microchannel structure and the molding of PDMS microchannel,was used to produce PDMS microchannel. Lithography combined with wet etching technolog was used to produce the glass concave microchannel. The effects of etching liquid ingredient, consistency and etching time on etching effect and geometric structure were investigated by means of a series of comparison experiments, respectively. PDMS and curing agent were mixed at the ratio of 10:1 with the curing temperature 90℃and curing time 30min.Glass gibbous microchannel template was presented by the identical process. Scanning Electron Microscope(SEM) was employed to character the geometry structure and surface conditions. Experiment results showed that:PDMS substrate based on glass gibbous microchannel template could be easily presented while with much defect.The UV-modification technology of PDMS was studied by Contact Angle Measurement System and XML Paper Sepecification(XPS), and the technology parameters were determined as well as the mechanism of modification also be discussed.The array electrodes were produced by method of photolithography and stripping.and a PDMS-glass microfluidic chip integrating the array of electrodes was bonded efficiently. UV modification was adopted on PDMS substrate and PDMS coverslip, and the entire PDMS microfluidic chip was bonded. Bonding strength testing results showed that:the strength of PDMS mixture microfluidic chip was greater than 0.82MPa and the strength of the whole PDMS microfluidic chip was about 0.21MPa.The electrokinetic driving theory of the micro fluid in the micro fluidic controlling chip was introduced. The experiment results showed that the linear area of V-A curve of the PDMS chip is 800V and the fluid in the microchannel was drived by 500V electric-field.