孟冀豫^{1, 2}，戴士杰^{1, 2, 3}，李姗姗^{1, 2, 3}，于成壮^{1, 2}，魏春阳^{1, 2}，李军委⁴
AuthorsHTML:孟冀豫^{1, 2}，戴士杰^{1, 2, 3}，李姗姗^{1, 2, 3}，于成壮^{1, 2}，魏春阳^{1, 2}，李军委⁴
AuthorsListE:Meng Jiyu^{1, 2}，Dai Shijie^{1, 2, 3}，Li Shanshan¹, ^{2, 3}，Yu Chengzhuang^{1, 2}，Wei Chunyang^{1, 2}，Li Junwei⁴
AuthorsHTMLE:Meng Jiyu^{1, 2}，Dai Shijie^{1, 2, 3}，Li Shanshan¹, ^{2, 3}，Yu Chengzhuang^{1, 2}，Wei Chunyang^{1, 2}，Li Junwei⁴
Unit:1. 河北工业大学机械工程学院，天津300401；
2. 河北工业大学河北省智能传感与人机融合重点实验室，天津300401；
3. 河北工业大学电工装备可靠性与智能化国家重点实验室，天津300130；
4. 河北工业大学廊坊分校计算机电子系，廊坊006500
Unit_EngLish:1. School of Mechanical Engineering，Hebei University of Technology，Tianjin 300401，China；
2. Hebei Key Laboratory of Robotic Sensing and Human-Robot Interactions，Hebei University of Technology，Tianjin 300401，China；
3. State Key Lab of Reliability and Intelligence of Electrical Equipment，Hebei University of Technology，Tianjin 300130，China； 4. Department of Computer Science and Electrical Engineering，Hebei University of Technology Langfang 006500，China

Abstract_Chinese:微流体交流电热效应混合是缩短药物筛选时间的有效手段之一．混合机制通常由微电极诱导流体内部产生温度梯度，从而形成涡流用于整个样品区域内的流体搅拌．但生物流体电导率偏高，交流电热的温升容易影响药物活性．因此，设计并封装一款环形微流体混合芯片，在不损失混合效率的前提下抑制流体的温升，揭示该芯片的混合性能，数值模拟与实验对微通道内两相流体的动态混合过程进行定量分析，并对模型几何参数、物理参数等条件进行优化研究．首先，利用Comsol仿真软件进行电场、温度场、流场以及稀物质传输场的强耦合仿真计算，以混合效率为目标函数，同时以温升上限作为约束条件，优化电压幅值以及微电极阵列的尺寸和分布．仿真结果表明，在给定电压下弧形微电极阵列的分布模式以及尺寸大小是影响混合效率的主要因素，电极对称/非对称分布诱导不同形式的非匀强电场空间分布，电极尺寸直接影响电场对流体的作用力范围．综合温升研究，仿真最优混合效率可达98.67%．然后，以优化的电极尺寸参数加工氧化烟锡微电极阵列，软光刻加工聚二甲基硅氧烷微通道．将上述带有特定微通道图案的PDMS与微电极玻璃基底封装后形成最终的微混合实验芯片．最后，使用电导率为0.2S/m的蓝色染料溶液和去离子水缓冲液(经0.9% NaCl溶液调节电导率值)进行混合实验，微混合器混合效率可达93.16%．
Abstract_English:The application of the AC electrothermal(ACET)effect of microfluids is one of the effective methods to increase the mixing efficiency of microfluids and reduce the time of drug screening. The ACET mechanism is usually induced by a microelectrode to generate a temperature gradient within the fluid，thereby creating a vortex that is used to stir the fluid throughout the sample area. However，because the conductivity of biomicrofluids is usually high，the ACET effect easily leads to higher temperature rise and causes negative effect on the drug activity. A micromixer chip with the characteristics of high mixing efficiency and lower temperature rise was designed based on ACET theory and fabricated in this work. The dynamic mixing process of two-phase fluid in microchannel was quatifatively analyzed by numerical and experiment methods. Next，the geometric size of the model and the physical parameters related to the mixing efficiency were optimized. In this optimization process，first，the strong coupling of electric field，temperature field，flow field，and transport of diluted species field is examined via Comsol simulation software. The mixing efficiency is set as the objective function and the maximum temperature rise is set as the constraint condition to optimize the voltage and the size and distribution of the microelectrode array. The optimized simulation results show that the distribution pattern and size of the arc-microelectrode array are the main factors affecting the mixing efficiency under a certain voltage value. The mixing efficiency can reach 98.67%. According to the optimized parameters，an indium tin oxide(ITO) microelectrode array is fabricated and PDMS is used to fabricate the microchannel using the method of soft lithography. Microelectrodes are fabricated via ITO glass lithography. The PDMS exhibiting a specific microchannel pattern is attached to the glass substrate with the ITO microelectrodes to form the final micromixer chip. Finally，deionized water and blue dyes were selected as two-phase experimental microfluids with the conductivity adjusted to 0.2S/m using 0.9% NaCl solution to perform the mixing effect of the chip. The experimental results show that the mixing efficiency of the micromixer can reach 93.16%.
Keyword_Chinese:交流电热；混合；微电极；温升；微流控芯片
Keywords_English:AC electrothermal；mixing；microelectrodes；temperature rise；microfluidic chip

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