Inspired by the natural Bouligand structure, researchers have been developing advanced materials for applications in impact-resistant bioplastics, ceramic armor, and biomimetic alloy composites. Most existing materials are still composed of single-scale brittle units despite the progress in improving the plasticity of materials. The lack of hierarchical active interfaces and autonomous response capabilities limits their ductility and overall functionality.
Therefore, researchers aim to develop Bouligand-structured materials with multi-level active interfaces, dynamic responsiveness, and enhanced toughness. By balancing micro-movements with structural stability, they seek to resolve the long-standing trade-off between brittleness and toughness, addressing key technical challenges in the practical application of biomimetic materials.
In a study published in Materials Today , a research team led by Prof. QING Guangyan from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) designed and fabricated a high-strength, reconfigurable, and mechanochromic cellulose photonic hydrogel.
The team developed an innovative strategy to construct Bouligand structures with promising applications based on the self-assembly properties of cellulose nanocrystals (CNCs). This strategy achieved the precise control over the network matrix alignment through nanofiber sliding and hydrogen bond reconstruction, driven by water-activated hydrogen bonding interactions.
The resulting photonic hydrogels exhibited impressive mechanical properties with toughness increasing fivefold and stretchability exceeding 950% compared with the original hydrogel. They also exhibited dynamic color-changing abilities, switching reversibly between red and blue, while maintaining stable electromechanical sensitivity even under repeated stretching. The photonic imaging interface is highly durable and can be reused, requiring only a five-minute water soak to restore its functionality.
"This work provides a new way for the practical application of CNCs, with potential uses in sustainable bioplastics, flexible electronic substrates, and smart photonic devices," said Prof. QING.
