Biomimetic Method Synthesis of HgS/Polyurethane Composite Film and Its Sensing Properties to Ba²⁺

Polyurethane-conjugated HgS nanocrystals with tunable sizes prepared by using biomimetic method. The obtained HgS nanoparticles with good dispersibility were characterized by Fourier transform infrared. Scanning electron microscopy are used to envisage the binding of nanoparticles with functional groups. The polyurethane molecules can control nucleation and growth of HgS crystals by binding on the surface of nanocrystals to stabilize nanoparticles. Quantum confinement effect of polyurethane-conjugated HgS nanocrystals was confirmed by UV-Vis spectra. The nanoparticles exhibit a well-defined emission feature at about 291 nm. The fluorescence results reveal that the PU/HgS nanoparticles film is sensitive to Ba²⁺, and a small amount of Ba²⁺ makes the emissions increase rapidly. The emission is hardly affected by other common ions in water. The nanocomposite film is possible to become a special sensor material for Ba²⁺.