Design And Fabrication Of Microfluidic Chip With Micropattern For Enhancing Mixing

Due to its high analytical sensitivity, large throughput, automatable analysis process and low cost derives form mass production, microfluidic chip has been greatly developed among chemistry, bioscience and biomedicine in recent years. However, the laminar flow in microchannel, caused by the scale reduction of flow channel, leads to the difficulty of mixing in microfluidic chip. Since mixing plays a significant part in realizing the various functions of microfludic chips, it then seems quite necessary to develop highly efficient micromixer. In this paper, micropatterns with large scope and well order are fabricated on the bottom of channel in microfluidic chip by oxidizing the pre-strained elastic substrate using oxygen plasma. When liquid flows past the microchannel with micropatterns, the lateral chaotic vortices will be generated in channel and disrupt the laminar flow, then the mixing intensity can be increased radically.This paper first hammers out the formulas of amplitude and wavelength of one-dimensional micropattern which will later guide the wrinkle pattern fabrication from the theory of wrinkle formation in sandwich panel. By altering the oxygen plasma treating time and using customized clamp, multitudinous micropatterns are produced on flat PDMS sheets. According to the factors like pattern amplitude, surface topography, sample flatness as well as the effect of pattern shape on mixing efficiency, fabrication parameters of micropattern can be determined.Then the serpentine and spiral microfluidic channels are designed and manufactured by virtue of the theory in designing chaotic convective micromixer. Patterned microchannels are produced based on former fabrication parameters, while the problem of patterned chip leakage is solved by using elastic mask.By injecting two flows of pure water dyed yellow and blue into microfluidic chip and calculating the ratio of the width of green region to the width of channel using image process software, the mixing efficiency of different kinds of microfluidic chips can be finally calculated quantitively.