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Abstract Electrowetting‐on‐dielectric (EWOD) has revolutionized digital microfluidics (DMF) by dynamically controlling surface wettability via electric fields. However, its reliance on external power, patterned electrodes, and complex circuitry limits device simplicity and portability. Here, tribo‐charge driven wetting (TCW) is introduced as a fundamentally new, electric‐free mechanism for active wettability control. Unlike voltage‐driven control in EWOD, TCW employs surface charges generated through contact electrification to modulate surface wettability, eliminating the need for electrodes, wiring, and power supplies. Using TCW, we demonstrate a substantial contact angle modulation of Δθ= 44.4°±1.1, achieved solely by a tribo‐actuator with its surface charge density of σ = −12.61 µC m⁻². Comprehensive experimental and numerical analyses reveal that TCW performance scales strongly with actuator area and charge density but is remarkably insensitive to dielectric thickness within a practical range. Leveraging these features, core DMF operations are demonstrated, including droplet transport, merging, and generation from a reservoir, all accomplished without any electric components. Droplet motion reaches speeds up to 40 mm s⁻¹, even across non‐planar terrains. Furthermore, fingertip‐controlled droplet manipulation highlights TCW's simplicity, cost‐effectiveness, and user‐interactivity. This work advances fundamentals of charge‐driven wettability control and establishes TCW as an electric‐free paradigm for active droplet control, opening new opportunities for resource‐limited, lab‐on‐a‐chip and point‐of‐care applications. 

A new lens capability for three-dimensional (3D) focal control is presented using an optofluidic system consisting ofn × narrayed liquid prisms. Each prism module contains two immiscible liquids in a rectangular cuvette. Using the electrowetting effect, the shape of the fluidic interface can be rapidly adjusted to create its straight profile with the prism’s apex angle. Consequently, an incoming ray is steered at the tilted interface due to the refractive index difference between two liquids. To achieve 3D focal control, individual prisms in the arrayed system are simultaneously modulated, allowing incoming light rays to be spatially manipulated and converged on a focal point located atP_focal(f_x,f_y,f_z) in 3D space. Analytical studies were conducted to precisely predict the prism operation required for 3D focal control. Using three liquid prisms positioned on thex-,y-, and 45°-diagonal axes, we experimentally demonstrated 3D focal tunability of the arrayed optofluidic system, achieving focal tuning along lateral, longitudinal, and axial directions as wide as 0 ≤ f_x ≤ 30 mm, 0 ≤ f_y ≤ 30 mm, and 500 mm ≤ f_z ≤ ∞. This focal tunability of the arrayed system allows for 3D control of the lens’s focusing power, which could not be attained by solid-type optics without the use of bulky and complex mechanical moving components. This innovative lens capability for 3D focal control has potential applications in eye-movement tracking for smart displays, autofocusing of smartphone cameras, or solar tracking for smart photovoltaic systems.