Preparation and study of photoswitchable fluorescence nanoparticles based on spirobenzopyran

The preparation and performance characterization of <50 nm spirobenzopyran-based photochromic nanocomposites with photoswitchable fluorescence are presented. The nanocomposites were fabricated by means of a modified miniemulsion polymerization process, in which the hydrophobic spirobenzopyran was covalently attached to the polymer chains and the matched fluorescent dyes were noncovalently embedded in the nanoscale cross-linked polymeric matrix, respectively. The obtained nanocomposites with a high relative fluorescence quantum yield (Q) exhibited superior fluorescent photoswitchable performance due to the effective photo-induced intermolecular energy transfer. The stability of photomerocyanine was also improved.

The opened form of photochromic spirobenzopyran component activates the photoinduced energy transfer process FRET and quenches the emission of the fluorescent component, while the closed form of spiropyran prevents FRET and restores the emission of the fluorescent component.Figure optionsDownload as PowerPoint slide