Combining Simple Deformations to Elicit Complex Motions and Directed Swimming of Smart Organic Crystals with Controllable Thickness

• Published in: Angewandte Chemie Vol. 64; no. 5; pp. e202416950 - n/a
• Main Authors: Zhu, Xiaotong, Xie, Mengyuan, Gao, Lin, Li, Liang, Naumov, Panče, Yu, Qi, Wang, Guoming
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 27.01.2025; Wiley-VCH Verlag
• Edition: International ed. in English
• Subjects: [4+4] cycloaddition; Actuation; Anthracene; anthracene derivatives; Aspect ratio; Chemical Sciences; Complexity; Controllability; Crystal growth; crystalline robots; Crystallization; Crystals; Deformability; Deformation effects; dynamic crystals; Formability; Mechanical properties; Microrobots; Organic crystals; Robot control; Robots; Robust control; Soft robotics; Swimming; Thickness; Ultraviolet radiation; dynamic crystals; crystalline robots; anthracene derivatives; [4+4] cycloaddition
• ISSN: 1433-7851; 1521-3773; 0044-8249; 1521-3773; 1521-3757
• DOI: 10.1002/anie.202416950

The lack of control over the crystal growth in a systematic way currently stands as an unsurmountable impediment to the preparation of dynamic crystals as soft robots; in effect, the mechanical effects of molecular crystals have become a subject of scattered reports that pertain only to specific crystal sizes and actuation conditions, often without the ability to establish or confirm systematic trends. One of the factors that prevents the verification of such performance is the unavailability of strategies for effectively controlling crystal size and aspect ratio, where crystals of serendipitous size are harvested from crystallization solution. Here we devised a water‐assisted precipitation method to prepare crystals of chemical variants of 9‐anthracene derivatives with various thicknesses that respond to ultraviolet light with simple mechanical effects, including bending, splintering, and rotation. By capitalizing on the robust mechanical flexibility and deformability of crystals, we demonstrate systematic variations in crystal deformation that are further elevated in complexity to construct crystal‐based robots capable of controllable motions reminiscent of sailing and humanoid movements. The results illustrate an approach to eliminate one of the critical obstacles towards complete control over the motility of dynamic molecular crystals as microrobots in non‐aerial environments. We report a water‐assisted precipitation method to prepare crystals with various thicknesses that respond to ultraviolet light with simple mechanical effects, including bending, splintering, and rotation. The resulting crystal‐based robots exhibit motions reminiscent of sailing and humanoid movements.