Photocontrolled self-assembly of silica nanoparticles

Herein we present a novel light-controlled assembly system, which is fabricated by functionalizing silica nanoparticles with coumarin. This system exhibits reversible morphological changes under alternating irradiation with 365 nm and 254 nm light: scattered distribution pattern, firework-shaped pattern, honeycomb pattern and donut-like pattern, due to the reversible photodimerization and photocleavage of coumarin. Furthermore, this system displays reversibly controllable wettability, which can be transformed between hydrophobic and superhydrophobic upon UV light illumination based on the photoresponsive of coumarin as well. The system with these interesting characteristics provides potential applications in the synthesis of controllable nanostructures by photo-regulation and self-cleaning fields.