Dual-Emissive Coating Films Prepared from Water-Borne Latexes of Acrylate–Vinylidene Chloride Copolymers: Their Room-Temperature Phosphorescence Properties and Sensing Abilities toward Solvents

Materials with a room-temperature phosphorescence (RTP) property have wide application fields. For practical applications, it is highly desirable that only a small amount of RTP phosphors was attached to the widely used hydrophobic polymers, especially the coating polymers, to avoid impairing the physical properties of polymers while reserving RTP function. In this work, aqueous latexes of copolymers of acrylate and vinylidene chloride (VDC) were prepared through the green emulsion polymerization in the presence of an extremely small amount of RTP phosphor (0.062 wt % relative to the solid), N-hydroxyethyl 4-bromo-1,8-naphthalimide (HBN). Once being excited, the hydrophobic soft films formed from these latexes were dual-emissive, including a broad fluorescence emission in the region of ultraviolet and blue light and a broad RTP emission signal covering from 530 to 690 nm under ambient condition (air, room temperature). X-ray diffraction and Differential scanning calorimetry characterizations demonstrated that the obtained acrylate–VDC copolymers had a very low crystallization degree, and their glass transition temperatures were around, even less than room temperature, much less than the ever-used rigid hydrophobic polymers for supporting RTP phosphors. The HBN-doped acrylate–VDC copolymer films emitted an orange color under UV light, and the emission color could respond reversibly to medium polar to nonpolar solvents.