Ionizing radiation induced degradation of poly (2-methoxy-5-(2'-ethyl-hexyloxy) -1,4-phenylene vinylene) in solution

Journal Article · Sat Oct 01 04:00:00 EDT 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3644946· OSTI ID:22038728

Bronze-Uhle, E S; Batagin-Neto, A; Lavarda, F C; Graeff, C F. O. ^[1]

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1. Department of Physics, FC-UNESP, Av. Eng. Luiz Edmundo Carrijo Coube 14-01, 17033-360 Bauru (Brazil)

In this paper we investigate the causes of the chromatic alteration observed in chloroform solutions of poly (2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV) after gamma ray irradiation. Structural and chemical changes were analyzed by gel permeation chromatography, fourier transform infrared spectroscopy, and proton nuclear magnetic resonance techniques and complemented by electronic structure calculations. The results indicate chlorine incorporation in the polymer structure and main chain scission after irradiation. Based on our findings we propose that the main mechanism for the blue-shifts, observed in the UV-Vis absorption spectra of MEH-PPV after irradiation, is the result of a radical attack on the polymer main chain. Gamma rays generate radicals, Cl and CHCl{sub 2} from chloroform radiolysis that attack preferentially the vinyl double bonds of the polymer backbone, breaking the electronic conjugation and eventually the chain. Our results indicate that oxygen does not play a major role in the effect. Electronic spectra simulations were performed based on these assumptions reproducing the UV-Vis experimental results.

• OSTI ID: 22038728
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 7 Vol. 110; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTRA
CHLOROFORM
DOUBLE BONDS
ELECTRONIC STRUCTURE
FOURIER TRANSFORMATION
GAMMA RADIATION
GEL PERMEATION CHROMATOGRAPHY
INFRARED SPECTRA
IRRADIATION
NUCLEAR MAGNETIC RESONANCE
ORGANIC POLYMERS
PROTONS
RADICALS
RADIOLYSIS
SPECTRAL SHIFT
ULTRAVIOLET SPECTRA
VISIBLE SPECTRA