Luminescent Carrageenan Hydrogels Containing Lanthanopolyoxometalates

In this research, we investigated the use of lanthanopolyoxometalates {LnPOM, K 9 [Ln(W 5 O 18 ) 2 ], Ln = Eu, Tb} as luminophores in thermosensitive polysaccharides such as carrageenan hydrogels. We demonstrate that the LnPOM species still show the characteristic photoluminescence bands of the Ln III ion when incorporated in the gel matrix. Moreover, the strength of the carrageenan hydrogels increases by increasing the amount of LnPOM added because of the effect of K + ions as cross‐linkers, but without compromising the photoluminescent behaviour. Nanoscale homogeneity is crucial regarding applications of hydrogels responsive to external stimuli. This research shows that the final LnPOM‐loaded hydrogels are homogeneous as a consequence of the diffusion behaviour of the luminophore species within the gel network. Therefore, we anticipate that the association of carrageenan hydrogels to luminescent lanthanopolyoxometalates might be of great relevance for optical devices and in particular for bioimaging techniques.