Recent Advances in Oriented Hydrogels: From Fundamental Mechanisms to Future Challenges

The poor mechanical properties and limited functionality resulting from the random network architecture of hydrogels have consistently restricted their practical applications. Biological systems leverage sophisticated anisotropic architectures to achieve exceptional mechanical and functional performance, inspiring the design of advanced hydrogels. This review first elucidates the orientation mechanisms existing in nature and subsequently systematically summarizes the multiscale reinforcement principles of oriented structures in hydrogels. Then, the mainstream design and fabrication strategies of oriented hydrogels, such as mechanical stretching, directional freezing, self‐assembly, and field‐assisted alignment, are scientifically classified and evaluated. Further, a detailed discussion and summary of the applications of oriented hydrogels in flexible actuators, soft robots, and tissue engineering, as well as the attractive role played by their oriented structures, is provided. Notably, this review also offers an initial discussion on the degradation mechanisms of oriented structures under environmental stressors, an overlooked yet vital aspect for practical applications. Fundamental challenges in scalability, dynamic reorientation, and long‐term stability are analyzed, charting pathways toward next‐generation high‐performance hydrogels.