Bioinspired Design of a Large‐Span Friction‐Switching Prototype Driven Synergistically by Adaptive Surface Hydration and Mechanical Strengthening

ABSTRACT Friction control plays a vital role in soft interfacial engineering. However, surface‐based regulation strategies are often limited by their modulation depth and range, while bulk regulation is constrained by the efficiency of mass and energy transfer. Achieving extremely large‐span friction switching in a soft contact system throughout the entire material remains a formidable challenge. Inspired by Sphagnum moss's through‐pore structures, we present a water‐triggered, adaptive, and penetrative friction‐switching prototype (APFP) that integrates penetrative hydration to simultaneously achieve mechanical switching and interfacial lubrication. APFP features biomimetic surface pores constructed by hydrophilic polymer brushes and lithium‐stabilized interconnected channels under phase separation, enabling rapid water penetration and throughout bulk modulus switching (>1000 times), along with a significant reduction in molecular chain damping (∼18 times). Unlike conventional surface regulation strategies, the APFP's penetrative mechanism allows for throughout property modulation, achieving over 100 times the coefficient of friction (CoF) switch (from ∼2.6 to ∼0.02). As proof of concept, APFP can be fabricated into intelligent medical devices with adaptive lubrication and self‐supporting mechanics, serving as sutures that reduce tissue‐piercing friction, while maintaining wound shape to prevent deformation. This work establishes a paradigm for constructing novel intelligent friction‐control systems and soft robotics.