Structural, dynamic and photophysical properties of a fluorescent dye incorporated in an amorphous hydrophobic...

The properties of a low molecular weight organic dye, namely 4-naphthyloxy-1-methoxy-2,2,6,6-tetramethylpiperidine, covalently bound to an apolar polyolefin were investigated by means of a multi-level approach, combining classical molecular dynamics simulations, based on purposely parameterized force fields, and quantum mechanical calculations based on density functional theory (DFT) and its time-dependent extension (TD-DFT). The structure and dynamics of the dye in its embedding medium were analyzed and discussed taking the entangling effect of the surrounding polymer into account, and also by comparing the results to those obtained for a different environment, i.e. toluene solution. Finally, the influence was investigated of long lived cages found in the polymeric embedding on photophysical properties, in terms of the slow and fast dye's internal dynamics, by comparing computed IR and UV spectra with their experimental counterparts.