Effect of glass transition temperature on the kinetics of the phase separation of excimer-forming dyes in amorphous polymers

POLY 120

Charles Sing, charles.sing@case.edu1, Brent R. Crenshaw2, and Christoph Weder, christoph.weder@case.edu2. (1) Department of Macromolecular Science and Engineering, Case Western Reserve Universtiy, 2100 Adelbert Rd., Cleveland, OH 44106, (2) Department of Macromolecular Science and Engineering, Case Western Reserve University, 2100 Adelbert Road, Cleveland, OH 44106-7202
Cyano-substituted oligo(p-phenylene vinylene) (cyano-OPV) dyes easily form excimers. Therefore the fluorescence maxima of their dilute solutions and crystalline forms display large differences (up to 140 nm). We recently demonstrated that such dyes can be employed for the design of optical threshold temperature sensors. Our approach relies on the ability to kinetically trap molecular mixtures of cyano-OPVs and amorphous host materials in a thermodynamically unstable glassy state via rapid quenching of melt-processed blends. Subjecting these blends to temperatures above their glass transition temperature (Tg) leads to permanent and pronounced changes of their PL emission spectra as a result of phase separation and excimer formation. We show here that the threshold temperature of this color change can be tailored by adjusting the Tg of the polymer matrix and that (at constant dye concentration) the kinetics of the aggregation process in these blends primarily depend on the difference between the annealing temperature and Tg.
 

General Papers: Polymers in Nanotechnology
6:00 PM-8:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix

Division of Polymer Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006