Stretchable Electronic Skins Realized by Confined In Situ Silver Patterning on Siloxane-Modified Polyimide

The rapid development of soft robotics and embodied intelligence demands electronic skins (E-skins) that are both mechanically self-adaptive and skin-conformal. However, the rigid aromatic backbones of conventional polyimides limit stretchability and hinder conformal integration with deformable surfaces. Here, elastically stretchable polyimide (es-PI) films are developed by incorporating aminopropyl-terminated siloxane spacers, while a confined-patterned in situ self-metallization strategy enables direct fabrication of patterned silver circuits. By spatially confining Ag⁺ coordination and reduction within predefined regions, this strategy produces continuous silver nanolayers with well-defined boundaries and robust metal-polymer interfaces, preserving electrical integrity during repeated deformation. The selected es-PI-0.5 substrate exhibits an estimated nominal elongation at break of approximately 96% and a tensile strength of approximately 25 MPa, while the corresponding metallized film retains electrical continuity during tensile deformation up to 50% strain. Device-level feasibility is demonstrated through a strain-dependent inductor-capacitor (LC) resonance response measured using a network analyzer and a separate smartphone-assisted near-field excitation experiment with rectified direct-current (DC) output detected using a multimeter. This work establishes a materials-circuit integration approach for stretchable electronic skins and skin-mounted sensing demonstrations.