Near‐Infrared Photodriven Self‐Sustained Oscillation of Liquid‐Crystalline Network Film with Predesignated Polydopamine Coating

• Published in: Advanced materials (Weinheim) 2020-04, Vol.32 (14), p.e1906319-n/a
• Main Authors: Lan, Ruochen, Sun, Jian, Shen, Chen, Huang, Rui, Zhang, Zhongping, Zhang, Lanying, Wang, Ling, Yang, Huai
• Format: Article
• Language: English
• Subjects: Biomimetics; Coating; Crystal structure; Crystallinity; Film thickness; Liquid crystals; liquid‐crystalline networks; Luminous intensity; Materials science; Near infrared radiation; near‐infrared‐light; Oscillators; polydopamine coating; programmable materials; Remote control; Solar power generation
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201906319

Movement is one of the vital features of living systems, and remote control of bioinspired soft robotic systems in a precise, contactless and harmless way is extremely desirable but challenging. A near‐infrared (NIR) photodriven polymeric oscillator is designed and fabricated by selectively coating a mussel‐inspired polydopamine (PDA) polymer layer on the surface of splay‐aligned liquid crystalline network (LCN) film. The oscillating motions of the LCN oscillators can be facilely manipulated by tuning light intensity and film thickness. More importantly, the programmability of the PDA coating enables the oscillating behaviors of LCN film to be predesignated and finely adjusted by coating the film with PDA locally and repeatedly. The self‐oscillating movement mechanism can be attributed to the temperature oscillation at the PDA‐coated LCN film since it is alternatively exposed and sheltered to the NIR‐light irradiations. Owing to over 50% NIR irradiation in solar spectrum, PDA‐coated film is found to oscillate upon exposure of focused sunlight, presenting great potential in fabrication of solar power generation devices. This provides a versatile strategy to fabricate NIR‐light‐actuated polymeric oscillators, providing inspirations in the development of biological soft robots and advanced biomimetic devices. Liquid crystalline network (LCN) film showing steady oscillation behavior driven by near‐infrared (NIR) light is prepared by selectively modifying the film with polydopamine coating, which makes the NIR‐light‐driven LCN oscillator designable and reprogrammable. It is found that the NIR light in focused sunlight is enough to actuate the oscillation, providing a new strategy to fabrication of solar power generation devices.