Rheofluorescence technique for the study of dilute MEH-PPV solutions in Couette flow.
J Fluoresc
; 15(3): 255-66, 2005 May.
Article
em En
| MEDLINE
| ID: mdl-15986152
ABSTRACT
A novel rheofluorescence technique has been developed that permits the study of fluorescent polymers in a near-uniform shear field. The system has been used to examine the effects of shear flow on dilute solutions of two commercially available samples of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) in toluene and xylene. A detailed description of the instrument is provided, along with data that confirm a small probe molecule, Rhodamine 6G, is not affected by simple shear flow. MEH-PPV solutions were examined over two decades of concentration for rheochromism indicative of changes in segment length, and shear-induced orientation revealed by measurements of the steady state emission anisotropy. It is demonstrated that these dilute samples were not influenced by shear rates in the range 100-1000 s(-1). In contrast, MEH-PPV dispersed in a concentrated polystyrene solution showed evidence of shear-induced orientation and rheochromism. This new technique shows promise for investigating the impact of shear flow on the conformation of conjugated polymers employed in organic optoelectronic devices.
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01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
J Fluoresc
Assunto da revista:
BIOFISICA
Ano de publicação:
2005
Tipo de documento:
Article