Characterization of an ultrathin polymer optode and its application to temperature sensors based on luminescent europium complexes

Abstract

This paper focuses on an ultrathin polymer optode containing europium complexes (p(DDA-Eu(TTA)₃Phen)). Ultrathin films were prepared by the Langmuir–Blodgett (LB) technique; a mixed solution of poly(N-dodecylacrylamide) (pDDA) and tris(4,4,4-trifluoro-1-(2-thienyl)-1,3-butanediono)-1,10-phenanthroline europium(III) (Eu(TTA)₃Phen) was spread onto a water subphase and the condensed monolayer was transferred onto a solid substrate. The spectroscopic properties and layer structure of p(DDA-Eu(TTA)₃Phen) LB films were investigated by UV-Vis spectroscopy, fluorescence spectroscopy, time-resolved luminescence decay measurement, X-ray diffraction, and surface plasmon spectroscopy. It was found that europium complexes were uniformly distributed in the ultrathin films compared with a cast film. The p(DDA-Eu(TTA)₃Phen) optodes showed efficient sensitivity to temperature in the range of 320 to 370 K. The findings demonstrate that the p(DDA-Eu(TTA)₃Phen) optode is a good candidate for temperature sensitive sensors.