Fluorescence dynamics of 6-(N-(7-nitrobenz-2-oxa-1,3-dazo1-4-y1)amino) hexanoic acid(NBD) was used to probe molecular motion in polystyrene (PS) thin and ultrathin films. NBD was tagged to phenyl group of PS with the concentration of 1.3 × 10-2 mol %. Polymer films with various thicknesses were prepared onto quartz plates by a spin-coating method. Excitation light with the wavelength of 435 nm was irradiated onto the films, and the fluorescence was observed by a spectrometer. Fluorescence intensity per unit thickness (Iu) decreased with decreasing thickness. Since Iuis closely related to fluorescence quantum yield, the result indicates that the quantum yield in the film decreased with decreasing thickness. Based on the analysis using a model composed of surface, bulk and interfacial layers, I u of the surface and interface layers was claimed to be smaller and larger than the bulk value, respectively. This implies that local free volume and/or molecular motion with a relatively small scale at the surface and interface are/is different from those/that in the bulk. The detailed discussion will be presented in a poster.
|Number of pages||1|
|Publication status||Published - Oct 19 2006|
|Event||55th SPSJ Annual Meeting - Nagoya, Japan|
Duration: May 24 2006 → May 26 2006
|Other||55th SPSJ Annual Meeting|
|Period||5/24/06 → 5/26/06|
All Science Journal Classification (ASJC) codes