Chiral fluorescent liquid crystal polymers containing 4-bromo-1,8-naphthalimide – synthesis and properties

By introducing two cholesteric liquid crystal monomers with different chain lengths (M1 and M2) and brominated naphthalimide fluorescent monomer (M3) into polymethyl hydrosiloxane, a series of fluorescent cholesteric liquid crystal polymers (FL-LCP) was prepared, which not only have excellent performance of liquid crystal and fluorescence but also own performance of selective reflection. Their chemical structures were confirmed to be in accord with molecular design by FT-IR and 1 H NMR spectroscopy, and found them with excellent thermal stability, mesomorphic behaviour and thermal performance by TGA, POM, DSC and XRD, and confirmed all the polymers belonged to the cholesteric phase. The FL-CLCPs emitted different intensity fluorescence under UV light, and conclusions about the relationship between fluorescence and temperature had been drawn. A comparative study was conducted on the fluorescence properties of powders and films of monomers and polymers.