In this paper, we present a 3D multimodal router for aqueous microdroplets, addressing the ongoing challenge of 3D transportation of microdroplets in free space. Our strategy combines the photovoltaic effect of a LiNbO:Fe substrate with the triboelectric effect of a superhydrophobic coating. We demonstrate that by positively charging the aqueous microdroplets through the contact-electrification process while they roll or elongate on the superhydrophobic surface, we can achieve their controlled and electrostatically ballistic ejection for free-space transportation. Leveraging the superfast and repetitive laser-scanning capabilities of a laser marking system, we develop various 2D/3D routing modes that utilize repulsive or attractive electrostatic forces to deflect or trap the microdroplets in parallel or cascading configurations. We propose a 3D routing mode suitable for photosensitive microdroplets, employing asynchronous illumination with an appropriate ON/OFF duty ratio. We also enable the 3D omnidirectional routing of initially motionless and traveling microdroplets using toroidal and linear laser-scanning, respectively, thus facilitating the transportation of sequential microdroplets in overpass configurations. Our proposed technique opens up new possibilities for free-space microfluidics, enabling the complex delivery of biochemical substance.

中文翻译：

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基于光伏和摩擦电效应协同作用的 3D 多模态、全向水微滴路由器

在本文中，我们提出了一种用于水性微滴的 3D 多模态路由器，解决了自由空间中微滴 3D 传输的持续挑战。我们的策略将 LiNbO:Fe 基底的光伏效应与超疏水涂层的摩擦起电效应结合起来。我们证明，当水性微滴在超疏水表面上滚动或伸长时，通过接触起电过程使水性微滴带正电荷，我们可以实现它们的受控静电弹道喷射，以实现自由空间传输。利用激光打标系统的超快和重复激光扫描功能，我们开发了各种 2D/3D 路由模式，利用排斥或吸引的静电力以平行或级联配置偏转或捕获微滴。我们提出了一种适用于光敏微滴的 3D 路由模式，采用具有适当开/关占空比的异步照明。我们还分别使用环形和线性激光扫描对最初静止和移动的微滴进行 3D 全向路由，从而促进立交桥配置中连续微滴的运输。我们提出的技术为自由空间微流体开辟了新的可能性，实现了生化物质的复杂输送。