Cellulose Nanocrystal-Based Robotic Devices for Encrypted Information Transmission

Degree of circular polarization (DOCP) of reflected light is an intriguing optical phenomenon of chiral photonic materials; however, it remains underexploited. This is especially the case with cellulose nanocrystals (CNCs), despite the fact that their angle-dependent structural color has been overwhelmingly attended to. Herein, CNC-based chiral photonic materials capable of dual actuation are constructed by vacuum-assisted self-assembly. Leveraging femtosecond laser machining, complex structural color 3D shapes, and crawling robotic devices are produced from these materials. The incident angle-incident lasing wavelength-reflected light DOCP correlation and DOCP-based ternary code are established, based on which a secure and efficient robotic information transmission strategy is presented, where a message is simply synthesized from structural color photos using a single-use key and the encryption security increases with photo numbers by power law. Our work unleashes the hidden potential of CNC-based soft actuators and enables them for secure and efficient robotic data transmission.