Photochromic latexes are a class of smart materials increasingly
valued for their diverse applications such as anticounterfeiting inks
and rewritable surfaces. These latexes have the ability to undergo
reversible color changes upon exposure to light. An ideal photochromic
compound should exhibit rapid switching upon light irradiation. Among
different photochromic compounds, 1,3-diazabicyclo[3.1.0]hex-3-ene
(DBH) compounds stand out for their excellent performance in both
these aspects, and their photochromic behavior consists of rapid switching
between closed-ring and open-ring forms under UV irradiation in both
solid and aqueous states. Here, a photochromic compound, DBH-GA, derived
from DBH compounds, was synthesized in turn through the reaction of
4-nitroketoaziridine and a natural sugar, galactose (GA), which has
not been reported yet. Then, latexes containing different ratios of
methyl methacrylate (MMA), acrylamide (AAm), and hydroxyethyl methacrylate
(HEMA) monomers were prepared via emulsion copolymerization. Subsequently,
DBH-GA was incorporated into latexes for enhanced application and
performance by the doping technique to prepare photochromic latexes.
The reversible switching of photochromic latexes rapidly occurred
from colorless to yellow, blue, or green under UV light (245–400
nm) or upon sunlight exposure for 10 s either in the solid or solution
state, demonstrating their multicolor switching ability. These latexes
revert to a colorless form when exposed to visible light (578 nm)
or in darkness for 6–8 h. Furthermore, all fabricated latexes
showed a reversible color change over 10 cycles. The resulting photochromic
latexes were applied to papers and fabrics. Our investigation delved
into the potential applications of DBH-GA–latexes, including
their use as an anticounterfeiting ink for confidential documents
with a high level of security, creation of durable photochromic fabrics
and papers, development of smart artworks, and rewritable papers.
DBH-GA–latexes with fast photoswitchability, environmental
compatibility, easy use on different substrates, and dynamic multicolor
switching showed great potential as smart materials in various applications.