There are numerous bionic gripping ends adapted to different environments, but stable gripping for curved objects in wet environments is still an urgent engineering challenge. In this study, inspired by the biological properties of tree frogs, a bionic friction pad with an inner concave micropillar surface (CMF-Pad) is proposed. Through the analysis of Hertzian contact theory, the optimization mechanism of the concave surface on the contact area is revealed, and the critical curvature range of the micropillar array to guarantee the drainage performance is deduced. Experiments have confirmed that CMF-Pad exhibit significant advantages in wet environments (≥10 mg/cm² liquid film environment), its micro-channels can actively drain interfacial fluids to enhance friction, and its transverse friction is increased by about 40% compared with flat/smooth friction pads; Simultaneously, it possesses excellent curved surface adaptation and torsion resistance. In the smooth surface contact life test, the CMF-Pad maintained more than 90% of its initial friction after 10,000 cycles of contact testing. Concurrently, practical applications have verified the stability of the friction pads when gripping, handling and twisting curved objects such as medical reagent bottles by robotic arms, enables reliable manipulation in liquid-mediated interfaces through dual mechanisms: active drainage and curvature-conformal contact, providing a different solution for humid environment operation in semiconductor processing, medical equipment handling and other fields.

The increasing demands for adaptive interfacial control across harsh conditions, from deep-space microgravity to deep-sea hydrostatic pressure, have propelled bioinspired structural adhesion/friction materials (SAFMs) into a transformative scientific frontier. Guided by nature’s evolutionary masterstrokes, the hierarchical fibrillar architecture of the gecko enables anisotropic van der Waals adhesion, and the muscular-hydrodynamic suction synergies of the octopus have engineered interfaces with unprecedented environmental adaptability. Despite breakthroughs in robotics and biomedicine, synthetic SAFMs persistently lag behind their biological counterparts in three dimensions: structural hierarchy fidelity, dynamic stability under cross-media disturbance, and adaptability to concurrent multiple environments. Through a comparative analysis of biotic/abiotic mechanisms, we demonstrate how current state-of-the-art synthetic systems, which are often limited by single-environment optimization or manufacturing-compromised structural hierarchies, fail to match the robustness of natural systems. To overcome these barriers, we propose a codesigned framework that integrates multiple mechanism synergies, multiple functional material networks, and bioinspired fabrication technologies. By bridging these domains, the framework aims to realize multiple environmentally adaptive bioinspired adhesions/frictions that transcend current application silos from space environments that are tolerant of robotics for lunar exploration to self-adjusting biomedicine devices for health monitoring.

With the development of human spaceflight, the impact of the microgravity environment in space stations on the work and life of astronauts has received increasing attention. For astronauts, establishing stable and switchable attachments to multiple surfaces in an orbiting space station is important and yet a great challenge. Here, inspired by the variable stiffness structures of biological adhesion organs with different functional directions, a multi-modulus adhesive unit is designed. The low-modulus adhesive layer provides good adaptability by mimicking the soft bottom of the rock-climbing loach suction cups and the setae on the gecko’s toes; the high-modulus flat substrate provides good stiffness to suppress deformation; the elasticity adaption layer reduces preload required for attachment to uneven surfaces like gecko muscular tissues, and the detachment switch made from nylon rope allows switching the adhesion force by adjusting the angle of force. Experiments in simulated microgravity environments demonstrate the ability of the adhesive shoes to rapidly generate strong and switchable adhesion and friction on rough surfaces, and tests in China's space station show that adhesive shoes based on multi-mechanism adhesion are a viable option for lower limb muscle exercising.

The crawling process of snakes is known to have fascinating tribological phenomena, whereas investigations on their frictional properties depending on patterned cuticles are insufficient. In this study, we have designed and fabricated biomimetic microstructures inspired by the geometric microunits of Achalinus spinalis cuticle using polyurethane acrylate (PUA) material and performed its tribological analysis. The micro-morphology of this Achalinus-inspired textured polymer surface (AITPS) is characterized by the closely and evenly quasi-rectangular microgrooves, periodically arranged along certain orientations. We have compared the frictional performance of our fabricated AITPS with other competitive microstructure, using a smooth steel ball and commercial clay as an interacting surface. After performing massive friction tests with steel ball and clay, AITPS still maintains good resistance reduction performed compared to the patterned surface with straight microgrooves, which is most likely due to the reduction of actual contact areas at the frictional interface.