Synthesis and photophysical properties of rhodamine B dye-bearing poly(isobutyl methacrylate-co-2,2, 2-trifluoroethyl methacrylate) as a temperature-sensing polymer film

To develop a novel temperature-sensitive paint, methacrylamide monomers bearing Rhodamine B dye (two regioisomers, 3a and 3b) were synthesized and polymerized with isobutyl methacrylate and 2,2,2-trifluoroethyl methacrylate to afford Rhodamine B-pendant polymers 4a and 4b. The methacrylamide monomers 3a and 3b showed photophysical properties almost identical with those of Rhodamine B. The temperature sensitivity of the luminescence intensity of 3a and 3b was also similar to that of Rhodamine B. The polymers 4a and 4b have excellent solubility in nonpolar organic solvents and are suitable for application as paint. Films of polymers 4a and 4b showed temperature-dependent luminescence, which is applicable for temperature-sensing. The temperature sensitivity of the film of 4a was estimated to be -0.37% degrees C-1, and was independent of pressure. The film of 4b showed higher temperature sensitivity, but its temperature sensitivity was slightly pressure-dependent. Hence, polymer 4a is expected to be superior for practical use in paints having temperature-sensing functionality. (c) 2007 Wiley Periodicals, Inc.