Easy-to-morph printable conductive Marangoni-driven 3D microdome geometries for fingertip-curved e-skin array with an ultragentle linear touch

Abstract

Continuously printable electronics have the significant advantage of being efficient for fabricating conductive polymer composites; however, the precise tailoring of the 3D hierarchical morphology of conductive nanocomposites in a simple dripping step remains challenging. Here, we introduce a one-step direct printing technique to construct diverse microdome morphologies influenced by the interfacial Marangoni effect and nanoparticle interactions. Using a jet dispenser for continuous processing, we effectively fabricated a soft epidermis-like e-skin containing 64 densely arrayed pressure sensing pixels with a hierarchical dome array for enhanced linearity and ultrasensitivity. The e-skin has 36 temperature-sensing pixels in the outer layer, with a shield-shaped dome that is insensitive to pressure stimuli. Our prosthetic finger inserted with the printed sensor arrays was capable of ultragentle detection and manipulation, such as stably holding a fragile biscuit, using a soft dropper to elaborately produce water droplets and harvesting soft fruits; these activities are challenging for existing high-sensitivity tactile sensors.