Nano-imprinting Technology To Fabricate Micro-nano Fluidic Chip And Its Applications

Microfluidic is the technology that operates or manipulates small amounts of fluids (nano-litre to p-litre) with channels in the dimension of tens to hundreds of micrometers. Unlike macroscopic systems, fluids in the microfluidic chip have many new phenomena due to the effects of scale, which is expected to promote the development of bio-sensing and analytical chemistry.With the developmemt of microfluidic chip in the area of biological and chemical and the progress of nano-processing technology, nanofluidic chip has drawn increasing attention. Both the basic and applied research of nanofluidic is based on the fabrication of nanofluidic chip. As the channels go down to nanometer scale, there are more requirements for more advanced processing technology. In nanometer scale, unique properties of fluids emerge, for example, increased viscosity,reduced electroosmotic flow, these special properties will play an important role for biological and chemical application.Micro/nano fabrication cannot be achieved without advanced lithography technology. Traditional lithography will meet great challenges when patterning nano-scale structures, meanwhile, some advanced lithography technique such as X ray lithography, electron beam lithography, etc. is too expensive and not suitable for mass production. As one of the most promising techniques that have been intensively studied, nanoimprint has been applied in circuit integration, memory, mico/nano channel, and micro/nano optic area.In this article, we used nanoimprint technology to fabricate polymer nanofluidics, by optimizing the bonding process parameters, we successfully fabricated SU-8 nanochannels in the dimension of 100nm with good channel profile. In addition, we also combined the nanoimprint technology with sacrificial layer method and successfully fabricated PZT (Pb (Zrx, Ti1-x) O3) nanochannels, the minimum size we have achieved is only 50nm. We also integrated SU-8 phase gratings into the bottom of SU-8 microchannel and successfully created microfluidic device which can detect the refractive index of fluids in the channel, the measured results agreed well with the theoretical simulation. We also studied the preparation condition of PDMS, surface modification and bonding method, the phenomenon of laminar flow is also studied and a microfluidic mixer has been created and used in the rapid mixing of liquids.