Determination of the elastic modulus of poly(ethylene oxide) using a photoisomerizing dye

We have newly explored a correlation curve between the fluorescence lifetime of an isomerizable dye (4-DASPI) and the Young's modulus of polymer matrices in which the dye were embedded. Then, the Young's modulus of poly(ethylene oxide) and its nanocomposites were calculated from the measured fluorescence lifetime of the probe through a formula that represents the modulus-lifetime relationship. Our approach opens a viable way with which the mechanical properties of soft materials, polymers, multilayer films, and cells can be obtained using various fluorescence probes, as long as a light-induced molecular motion lies in the modulus or elasticity controlled regime. (C) 2012 Elsevier B. V. All rights reserved.