Papers by Author: Xiao Wei Han

Abstract: In this paper, we presented a novel method for fabricating the integrated electrochemical sensor based on a microfluidic device. The device included: printed circuit board (PCB) substrate with vertical embedded electrodes; polymethyl methacrylate (PMMA) with micro structures; PMMA cover with amperometric detection sensor (ADS). The ADS employed three-electrode sensor system which was composed by two Au electrodes and an Ag/AgCl reference electrode. The polyvinyl chloride (PVC) membrane was used as ion-exchange medium of reference electrode and installed between Au electrodes. Then, the potential changes and the standardization oxidation-reduction experiments were executed to characterize the integrated reference electrode performance. Finally, the ADS system was tested by cyclic voltammetry (CV).

Abstract: In this paper, we focused the mixed results of the micromixer with the same quantity of electrodes but different placement. We imposed time dependent electric potential on different electrodes under the low Reynolds number condition, and then evaluated the impact of electrode position to the mixed results and summarized some rules which were conducive to achieving mixed. According to the simulation results and combined with the assembly process, we obtained the optimal number and placement of microelectrodes.

Abstract: In this paper, we fabricated a novel multilayer microfluidic device with vertical embedded electrodes. The device was composed of printed circuit board (PCB) substrate with vertical embedded electrodes, the polyimide insulating layer and the polymethyl methacrylate (PMMA) with micro structures. The vertical electrodes were made by metal wire and integrated on the PCB substrate, they can be replaced when fail or broken. In addition, we investigated the relationship between electrodes height and the electro-osmotic flow by using numerical simulation. The results show that, with the increase electrodes height inside the microchannel, the speed of electro-osmotic flow increased and concentration field distribution improved significantly.

Abstract: In this paper, we design and fabricate a three-dimensional passive-micromixer with a replaceable mixing chamber. The rectangular mixing chamber has a dimension of 20 mm × 3 mm in length and width and 2 mm in height, the chamber can be fitted with different microstructures to accelerate mixing. Then, we compare the no structure chamber to left and right interdigitated chamber by using numerical simulation, the result show that the mixing efficiency has been significantly improved. The photomicrographs proved the effectiveness of the design finally.

Abstract: A new bonding technique mainly for PMMA microfluidic chips is presented in this paper. In this technique, polymer microfluidic microchannels were bonded by microwave radiation. Its strength and time can be controlled accurately in watt and second level. There are so many techniques for mass-production of polymer microfluidic chip, such as heat bonding, ultrasonic bonding. However, we may find different kinds of shortages when we use these techniques. In this paper, the experiment result shows that microwave radiation’s strength and time have effects on microfluidic chip`s bonding strength. The microwave absorbing coating can also have a certain degree influence on microfluidic chip`s bonding strength.

Abstract: A new manufacture mainly for polymethyl methacrylate (PMMA) microfluidic chips is presented in this paper. In this technique, polymer microfluidic microchannels were fabricated by microcutter which temperature is controlled and stabilized by PID methord. There are so many techniques, such as hot embossing, laser direct-write, for mass-production of polymer microfluidic chip. However, we may feel different kinds of shortages when we use these techniques. In this paper, the experiment result shows that microcutter’s movement velocity and temperature have effert on microfluidic microchannel’s roughness.