Concentric ice-templating of ultracompressible tough hydrogels with bioinspired circumferentially aligned architecture
- Wenxi Gu
- Shuqi Yang
- Dazhe Zhao
- Yiwei Zou
- Chonghao Chen
- Peiqi Niu
- Xiangyu Liang
- Chi Tat Kwok
- Bingpu Zhou
- Chunming Wang
- Yan Yan Shery Huang
- Ji Liu
- Iek Man Lei
2025-06-20
Materials with circumferentially aligned fibers, such as intervertebral discs and arteries, are abundant in nature but challenging to replicate artificially, despite their mechanical advantages. Although ice-templating can create bioinspired materials, the achievable structures remain limited to simple forms, such as honeycomb, lamellar, and radial structures. Here, we developed a unique ice-templating technique that constructs circumferential fibrous structures in hydrogels through slow freezing. Enhanced with rotary compression annealing, these hydrogels exhibit record-breaking features that cannot concurrently be achieved in conventional ice-templated and top-performing tough hydrogels, including high tensile properties, isotropic fatigue threshold of 2320 joules per square meter, ultracompressibility (8% strain after 500 cycles), and extraordinary burst pressure of 1.6 bar while maintaining 85 weight % water content. These properties enable opportunities in robotics, including hydrogel pneumatic grippers and an untethered bioinspired robotic fish that exhibits high-force actuation and long-term robustness. Our approach enriches the diversity of bioinspired structures in artificial materials, establishing exceptional mechanical properties through cross-length scale structural design.