Luminescent Cu2+ probes based on rare-earth (Eu3+ and Tb3+) emissive transparent cellulose hydrogels

Cellulose hydrogels are biodegradable materials that can be applied as accommodating hosts for various species. Here we report the preparation of novel thin films based on luminescent cellulose hydrogels. The spectroscopic behavior of these soft materials and their sensing effects are investigated. Interestingly, we found that these films only give selective signal changes in the presence of Cu(2+) in water in comparison with Na(+), K(+), Ag(+), Mn(2+), Co(2+), Ca(2+), Cd(2+), Hg(2+), Pd(2+), Mg(2+), Ni(2+), Fe(2+), and Fe(3+). High visible-light transmittance and good flexibility for these films can be observed. More importantly, the thermal stability of rare-earth complexes could be significantly enhanced in aqueous solution as result of the protection by hydrogel matrix.