Living organisms rely on materials sequestration from the environment to strengthen their bodies. Such constant activity provides necessary supplies for critical biological functions, which is difficult by man-made structures due to the lack of a dynamic sequestration mechanism. In this study, it is shown that an epidermis-like smart coating can respond to changes in salinity to allow a spontaneous and progressive strengthening when supported by steel as a sustained iron source. The self-strengthening is enabled by reaction-coupled diffusion, which makes possible the dynamic sequestration of iron from the in situ rusted steel, partially mimicking the iron accumulation process in a mussel. The emergence of iron–phenolic coordination bonds continuously improves modulus, hardness, and adhesion, achieving a strengthening efficiency comparable to mussel byssus. Interestingly, the bilayer design ensures long-term self-healing performance even during strengthening and a mechanically robust anticorrosion coating with an autonomic protection mechanism and gradually enhanced barrier properties during prolonged service. Our results provide a new venue for the design of stimuli-responsive smart materials characteristic of an open biological system and may serve as the basis for creating highly intelligent devices with sophisticated functionality.

生命有机体依靠从环境中隔离的物质来增强其身体。这种持续的活动为关键的生物学功能提供了必要的供给，由于缺乏动态的螯合机制，人造结构很难做到这一点。在这项研究中，表明表皮样智能涂层在受钢作为持续铁源的支持下，可以响应盐度的变化，从而实现自发性和渐进性的强化。通过反应耦合扩散实现自我强化，这使得从原位生锈的钢中动态隔离铁成为可能，从而部分模拟了贻贝中的铁积累过程。铁-酚配位键的出现不断提高模量，硬度和附着力，达到与贻贝类似的增强效率。有趣的是，双层设计即使在加固过程中也能确保长期的自我修复性能，并具有具有自主保护机制的机械坚固的防腐涂层，并在长期使用过程中逐渐增强了阻隔性能。我们的结果为开放式生物系统特有的刺激响应智能材料设计提供了新的场所，并且可以作为创建具有复杂功能的高度智能设备的基础。