Recently, professor Yang Hong of School of Chemistry and Chemical Engineering, Southeast University and his team made a breakthrough in near-infrared (NIR) light stimulated polymeric materials. The research results were published in the top journal “Journal of the American Chemical Society”.

In the past decade, near-infrared (NIR) light stimulated soft actuators with wide application prospects in tissue engineering, biomedical devices and robotic technology have attracted extensive scientific attention, in particular because the long-wavelength NIR light, compared with ultraviolet/visible light, could efficiently penetrate through biomaterials which rendered NIR the best biocompatible remote stimulus control. However, the real application of NIR-responsive soft actuators was plagued by two key limitations: moderate photoactuation speeds and poor mechanical properties, which were intrinsically caused by the exclusive, flawed physical blending preparation method of NIR-responsive soft actuators.  

The research team designed and synthesized a four-alkenyl-tailed croconaine-core cross-linker as the NIR absorbing chromophore, and further developed a two-step ADMET in situ polymerization/cross-linking method to fabricate a uniaxial aligned main-chain LCE soft actuator material. Taking advantage of the highly concentrated, homogeneous distributed, chemically bonded NIR chromophore units and the main-chain end-on mesogenic skeletal structure, this novel LCE soft actuator material exhibited an ultrafast photoresponsive speed and superior mechanical property. This design will pave the way for developing high-speed responsive, ultrastrong smart polymeric materials.

This research was supported by National Natural Science Foundation of China (21374016) and Jiangsu Provincial Natural Science Foundation of China (BK20170024). The research results were published in the top journal “Journal of the American Chemical Society”. The first author is doctoral candidate Liu Li.