Subvoxel‐Controlled Microfluidic Printing of Dual‐Material and Multi‐Structural Filaments

Filaments with multi‐materials, complex structures, and sophisticated functions are of great importance to wearable electronics, flexible actuators, and sensors. Direct ink writing (DIW) is mainly adopted to fabricate functional filaments. However, finely regulating the filament's structure is difficult due to the unmovable and static extruding nozzle parts. Here, a dynamically adjustable DIW platform is presented with a movable needle in a Y‐shaped microfluidic nozzle, enabling precise subvoxel control over the structure of the inner layer to print dual‐material and multi‐structure filaments. The position, proportion, and shape of the filaments’ inner layer can be precisely manipulated by adjusting the extruding pressure and the motion of the needle's position in the microfluidic nozzle. Therefore, filaments with various complex structures can be fabricated. Via the printing platform, wavy inner structures are manufactured for stretchable conductance‐stable and triboelectric nanogenerator fibers to realize energy harvesting and self‐powered sensing. Such subvoxel‐controlled microfluidic printing significantly increases the complexity of dual‐material filaments to provide potential applications for flexible electronics.