Abstract:

Miniemulsion polymerization technology has several advantages, including simple operation, use of green technology, and a wide range of applications, and can be used for innovative experimental teaching for undergraduates. By introducing spiropyran derivatives with photochromic properties into the miniemulsion polymerization, the prepared colloidal particles have apparent photochromic and photoswitchable fluorescent properties, which may further stimulate students' interest in experiments and foster a sense of closeness to scientific research. In this paper, a one-step miniemulsion polymerization method was used to prepare photochromic colloidal particles containing spiropyran derivatives, that's 2-(3', 3'-dimethyl-6-nitrospiro[chromene-2, 2'-indolin]-1'-yl)ethyl methacrylate (SPMA), at 75 ℃ for 3 h. The particle size and spectra of the colloidal particles were measured using a laser particle size analyzer, UV-Vis absorption spectrometer, and fluorescence spectrometer. The results show that the particle size of the prepared colloidal particles is approximately 60 nm, and they exhibit obvious photochromic and photoswitchable fluorescent properties under ultraviolet and visible light. Preliminary studies show they have valuable fluorescent anti-counterfeiting applications.

Key words: Miniemulsion polymerization, Photochromic, Colloidal particles, Spiropyran, Anti-counterfeiting