Spatially core-shell mussel inspired alginate hydrogel enabling adhesive outer layers and a reinforced inner network for intelligent pressure detection.

Inspired by the functional partitioning of biological interfaces, we report a core-shell-structured adhesive hydrogel (SA-Dopa hydrogel) that spatially decouples interfacial adhesion from bulk mechanical reinforcement for wearable sensing applications. Conventional one-pot adhesive hydrogels generally distribute adhesive moieties throughout the entire network, leading to coupled surface/bulk functions and inefficient use of interfacial binding groups. In this design, a Ca2+-coordinated sodium alginate inner network serves as a mechanically robust load-bearing framework, while a catechol-rich outer hydrogel layer provides mussel-inspired surface adhesion. This structure enables strong and durable adhesion to diverse substrates, enhanced mechanical strength and toughness, and stable deformation tolerance without sacrificing interfacial compliance. The resulting hydrogel further exhibits reliable electromechanical transduction, featuring strain-dependent sensitivity. Benefiting from the synergistic coupling of a reinforced interior and adhesive outer shell, the SA-Dopa hydrogel supports accurate detection of tensile and compressive stimuli, and Morse-code-assisted wearable communication. Of particular significance, the material can be readily integrated into wireless pressure-sensing arrays and intelligent grippers, enabling real-time pressure mapping, object-shape discrimination, and adaptive grasping feedback. This work establishes a simple yet effective strategy for spatially allocating adhesion and mechanics within a single hydrogel platform, opening a new route toward high-performance wearable sensors and intelligent soft robotic interfaces.