Multiscale‐Engineered Ionic Conductive Elastomer Paints for Direct Conformal Manufacturing of Multilayer Soft Ionotronics on 3D Curved Multi‐Material Surfaces

Abstract The seamless integration of ionotronic systems with complex 3D surfaces across diverse substrates remains pivotal for advancing high‐performance soft ionotronics. While conventional approaches relying on ex situ device fabrication and transfer struggle to achieve conformal integration, the very few existing in situ conformal fabrication techniques are predominantly limited to constructing single electrodes on specific materials rather than complete multilayered systems on diverse substrates. Herein, a universal ionic conductive elastomer paint (ICEP) platform is presented that enables direct conformal manufacturing of multilayer soft ionotronics on 3D curved surfaces of various substrate materials. The ICEP demonstrates versatile processability through brushing, printing, dipping, and spin‐coating techniques, forming ultrathin ionic conductive elastomer coatings (ICECs) that exhibit perfect conformality to underlying surfaces. Through a multiscale molecular design strategy, the resulting ICECs achieve largely tailorable mechanical properties (e.g., tensile strength up to 35.74 MPa, hysteresis ratio as low as 12%) to accommodate diverse substrate/application requirements while maintaining recyclability. By synergistically combining ICEP with engineered dielectric elastomer paints, functional layered ionotronic devices, such as moisture‐induced electricity generators and capacitive ionic skins are successfully manufactured, on geometrically complex surfaces of various substrates. This material platform establishes a universal paradigm for constructing adaptive soft ionotronics through direct surface‐conformal manufacturing.