Multiple micromixing in a controlled sequence is an essential process for complex chemical synthesis of functional nanoparticles with desired physicochemical properties. Herein, we developed a unique sequential micromixing-assisted nanoparticle synthesis platform utilizing alternating current electrothermal flow (ACET). A two-fluid micromixer comprised with pairs of staggered asymmetric electrodes was first designed and characterized by joint numerical simulations and experiments to obtain the optimized electrode configuration within a straight channel. On this basis, an extra pair of symmetric electrodes was added at the main channel entrance to form a three-fluid sequential micromixer. The middle fluid would first mix with the side fluids through the symmetric ACET microvortex pair in the upstream region and then realize the side fluid mixing by the asymmetric ACET microvortex in the downstream region. Rapid and complete mixing in a short channel was observed for a relatively high flow velocity up to 7 mm/s at an AC signal of 27.5 V and 1 MHz. Sequential micromixing was achieved by flexibly adjusting the volume of each fluid and the AC voltage within the three-fluid mixer. Both the two-fluid mixing process and the three-fluid mixing process were applied to synthesize the Co–Fe Prussian blue analogue nanoparticles. In comparison with two-fluid mixing, three-fluid sequential mixing offers nanoparticles with higher dispersion, controlled particle morphology, and more regular shapes. Therefore, the ACET flow-based sequential micromixing strategy can be an alternative for complex chemical and biochemical reactions.

中文翻译：

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利用交流电热流的三流体顺序微混合辅助纳米粒子合成

以受控的顺序进行多次微混合是具有所需物理化学性质的功能纳米粒子的复杂化学合成的基本过程。在这里，我们开发了一个独特的顺序微混合辅助纳米粒子合成平台，利用交流电热流（ACET）。首先设计了一个由两对交错的不对称电极组成的双流体微混合器，并通过联合数值模拟和实验对其进行了表征，以在直通道内获得优化的电极配置。在此基础上，在主通道入口处添加了一对额外的对称电极，以形成三流体顺序微混合器。中间流体将首先通过上游区域中的对称ACET微涡流对与侧流体混合，然后通过下游区域中的非对称ACET微涡流实现侧流体混合。在27.5 V和1 MHz的AC信号下，观察到在短通道中快速且完全混合，相对高的流速高达7 mm / s。通过灵活地调节三流体混合器中每种流体的体积和交流电压，可以实现顺序微混合。两种流体混合过程和三种流体混合过程均用于合成Co-Fe普鲁士蓝类似物纳米粒子。与二流体混合相比，三流体顺序混合可提供具有更高分散性，可控颗粒形态和更规则形状的纳米颗粒。因此，