Bionic Polyurethane with a Reversible Core-Sheath for Real-Time On-Demand Performance Adjustment and Fluorescence Self-Reflection.

Smart materials that can respond to external stimuli have attracted considerable scientific interest and achieved fruitful results with the advancement of research. However, materials with adjustable performance and which could be intervened on-demand through stimulation are still rarely mentioned. Furthermore, most of these materials published so far usually require high temperature or the assistance of catalysts to change the structure and adjust their performance, and the process is always irreversible. Herein, we proposed an anthracene-functionalized novel polyurethane with adjustable performance and fluorescence self-reflection inspired by shellfish. Anthracene was used as a dynamic group to make the polymer chain structure topologically isomerize after UV exposure, finally constructing a reversible core-sheath in a homogeneous polymer. Moreover, this process is catalyst-free and has strong spatiotemporal controllability. The appearance of the reversible core-sheath structure could achieve the performance adjustment of materials, and the strength can be increased easily in real time and on-demand by UV light exposure. Through selective irradiation, spatial control stiffening of this material can also be realized. In addition, the performance can also be self-reflected through the fluorescence to realize the performance that is visualizable. This work dramatically simplifies the requirements and conditions for material performance adjustment while expanding the versatility and applications in intelligent materials such as artificial muscles, variably flexible electronic devices, heterogeneous materials, 4D printing, and what may be discovered in the future.