Molecular rotor dynamics influenced by the elastic modulus of polyethylene nanocomposites

Abstract

We observed that the excited-state twisting motion of 3, 3′ -diethyloxacarbocyanine in polymer nanocomposites (PNCs) depends strongly on the elastic modulus of medium. PNCs consist of low density polyethylene dispersed with surface-functionalized nanodiamonds with various alkyl groups. The mechanical properties of the PNCs were measured by a nanoindentation method, and the photoisomerization processes of the cyanine dye doped in the composites were investigated by time-resolved fluorescence spectroscopy. It was found that the molecular rotor dynamics in rigid media should be quantitatively describable by the elastic modulus of polymer. © 2009 American Institute of Physics.