Cationic waterborne polyurethane fluorescent material based on 4'-p-N,N-bis(2-hydroxyethyl)benzyl-3,3':6', 2''- terpyridine (TPPDA-CWPU) was synthesized. The structure was characterized by FTIR and UV-vis spectroscopy. The content of TPPDA in the fluorescent polyurethane was 6.3×10-4 mg/mg and the grafting ratio was 33.87%. The numberaveraged and weight-average molecular weights of TPPDA-CWPU were about 16060 and 27131 g·mol-1, respectively. The maximum absorption wavelength of TPPDA-CWPU was blue shifted ca. 6 nm compared to TPPDA. TPPDACWPU showed different fluorescence properties under different solid content. Compared with 20% solid content, the fluorescence intensity of 1% solid content increased by ten times. The quantum yield of TPPDA-CWPU was 0.3, which was four times higher than that of TPPDA. Moreover, TPPDA-CWPU was sensitive to acidic condition and there was the phenomenon of fluorescence quenching in the case of strong acidic condition. It is believed that more applications will be possible in the pH-responsive polymer.

Keywords: fluorescence; 4'-p-N,N-bis(2-hydroxyethyl)benzyl-3,3':6'; 2''-terpyridine; waterborne polyurethane; cationic