We demonstrated the on‐chip synthesis of Au nanoparticles achieved by a microwave‐induced reaction in a microfluidic channel. The chip structure consists of a waveguide and a microchannel through the inside of the waveguide. A postwall waveguide, in which metallic posts are continuously arranged on the side wall, is utilized to confine microwave fields. This configuration allows a solution to be inserted inside the waveguide by the microchannel passing between the metallic posts. In order to realize the miniaturization of the chip, the 24.125 GHz industrial, scientific, and medical (ISM) band is utilized instead of the commonly used 2.45 GHz ISM band. When pure water is heated in the microchannel under microwave input power of 3.0 W, temperature increases to 70°C were confirmed. In this paper, this chip is adapted to synthesize Au nanoparticles via a microwave‐induced reaction. After irradiating at a microwave power of 3.0 W and an irradiation time of 5 min, we observed absorbance and dynamic light scattering of the reactant, and the results indicated the generation of Au nanoparticles. This microwave synthesis system allows us to achieve automatic and rapid selective synthesis of nanoparticles in a solution.

中文翻译：

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微波加热片上合成金纳米颗粒

我们展示了通过微流体通道中的微波诱导反应实现的Au纳米颗粒的片上合成。芯片结构由一个波导和一个穿过波导内部的微通道组成。利用后壁波导，其中金属柱连续地布置在侧壁上，用于限制微波场。这种配置允许通过在金属柱之间通过的微通道将溶液插入波导内部。为了实现芯片的小型化，使用24.125 GHz工业，科学和医学（ISM）频段代替了常用的2.45 GHz ISM频段。当在微波输入功率为3.0 W的情况下在微通道中加热纯水时，温度会升高到70°C。在本文中，该芯片适用于通过微波诱导的反应合成金纳米颗粒。在以3.0W的微波功率和5分钟的照射时间照射后，我们观察到反应物的吸收和动态光散射，结果表明生成了Au纳米颗粒。该微波合成系统使我们能够实现溶液中纳米粒子的自动，快速选择性合成。