Cyclosiloxane-Based AIE Molecular Assemblies for Fluorescent Superhydrophobic Surfaces

Naphthalimide (NI) fluorophores can be easily modified by a rigid and large steric aromatic group on its active position to emit characteristic luminescence such as aggregation-induced emission (AIE), which are of extensive interest for optoelectronic devices, fluorescence sensors, and biological imaging. A cyclosiloxane-modified NI molecule, HMCS-PhAN, was synthesized, and its AIE properties in THF solution were confirmed with the addition of a nonsolvent (water). The introduction of a cyclosiloxane unit was proved to have a higher AIE effect compared with an NI molecule having no cyclosiloxane unit. HMCS-PhAN was also introduced into the superhydrophobic suprastructures of a previously reported cyclosiloxane amphiphile (TMCS-DDA) by mixing HMCS-PhAN into TMCS-DDA solutions. Drop-casting films of the mixed solutions of HMCS-PhAN and TMCS-DDA were demonstrated with flower-shaped nanostructures, and their surfaces exhibited superhydrophobic and AIE properties. The combination of superhydrophobicity and AIE fluorescence properties is promising for waterproof chemical sensors and fluorescence devices.