Rakchart TraipholToemsak SrikhirinTeerakiat KerdcharoenTanakorn OsotchanNico ScharnaglRegine WillumeitNaresuan UniversityMahidol UniversityHelmholtz-Zentrum Geesthacht - Zentrum für Material- und Küstenforschung GmbH2018-08-242018-08-242007-02-01European Polymer Journal. Vol.43, No.2 (2007), 478-487001430572-s2.0-33846551981https://repository.li.mahidol.ac.th/handle/20.500.14594/24373In this report, the role of local polymer-solvent π-π-interaction on rotational dynamics of phenyl rings of poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylenevinylene] (MEH-PPV) is examined by utilizing nuclear magnetic resonance (NMR) spectroscopy. We have found that an aromatic solvent can couple strongly with the phenyl rings via favorable local π-π-interaction, causing a restriction of the ring rotation. The dynamic process takes place at much faster rate in a non-aromatic solvent. NMR line shape analysis indicates the existence of two side chain configurations with relatively long life-time in toluene and pyridine while a single time-averaged configuration is detected in chloroform and tetrahydrofuran. Addition of chloroform or cyclohexane to a solution of MEH-PPV in toluene is accompanied by an increase of the rotational dynamics. This indicates that the expansion or collapse of main chain upon varying solvent quality play a minor role on the rotational dynamics. The relationship between the dynamics of ring rotation and photophysics of MEH-PPV in solution is discussed. © 2006 Elsevier Ltd. All rights reserved.Mahidol UniversityChemistryMaterials ScienceArticleSCOPUS10.1016/j.eurpolymj.2006.11.022