A near-infrared light-driven composite for smart and robust adhesion based on dynamic photochemistry

-isomer transitions under NIR irradiation of high power and low power, respectively. Under high-power NIR light excitation, the high-intensity dynamic isomerization reaction of the complex not only caused "free volume expansion" but also led to structural changes at the condensed matter scale, thereby significantly decreasing its elasticity and viscosity. In addition, robust switching of its adhesion strength was demonstrated over six cycles. This study shows that the combination of azobenzene polymers and upconversion luminescent materials has great application potential as NIR photoresponsive materials.