Waterborne polyurethane/carbon quantum dot nanocomposite as a surface coating material exhibiting outstanding luminescent performance

A luminescent waterborne polyurethane (WPU)/carbon quantum dot (CQDs) nanocomposite has been prepared by incorporation of low dose levels (0.05, 0.15, and 0.25 wt%) of carbon quantum dots via an in stiu polymerization, using isophorone diisocyanate (IPDI), 1,4-butanediol (BDO) as the hard segment, polypropylene glycol(PPG) (Mn = 1000) as soft segment, dimethylolpropionic acid (DMPA) as hydrophilic monomer, and CQDs as a modified agent. We characterized the CQDs-WPU nanocomposite and investigated its properties by Fourier transform infrared spectrometer (FT-IR), fluorescence spectra, Thermogravimetric analyzer (TGA), scanning electron microscope (SEM), etc. The results indicated that CQDs was successfully introduced into the main chains of polyurethane. The incorporation of CQDs endowed CQDs-WPU nanocomposites the excellent mechanical properties and thermostability. Interestingly, the fabricated nanocomposite film exhibited good transparency and photoluminescence properties, the photoluminescence intensity of CQDs-WPU film increased with the increase of CQDs dosage, and an excitation wavelength independent photoluminescence behavior of CQDs-WPU was witnessed.