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Modifying the Electronic Character of Single‐Walled Carbon Nanotubes Through Anisotropic Polymer Interaction: A Raman Study
Author(s) -
Chen B.,
Cinke M.,
Li J.,
Meyyappan M.,
Chi Z.,
Harmon J. P.,
O'Rourke Muisener P. A.,
Clayton L.,
D'Angelo J.
Publication year - 2005
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200305027
Subject(s) - materials science , raman spectroscopy , carbon nanotube , anisotropy , composite material , composite number , dielectric , methyl methacrylate , polymerization , polymer , electronic structure , optoelectronics , optics , condensed matter physics , physics
Using Raman spectroscopy, we demonstrate that the anisotropic interaction between single‐walled carbon nanotubes (SWNTs) and poly(methyl methacrylate) (PMMA) causes significant changes in the electronic properties of their composites. Two different procedures were used to prepare the composites: melt blending and in‐situ UV polymerization. Resonant Raman studies relate the electronic density of states (DOS) of the SWNTs to the corresponding vibration symmetry changes of both the PMMA and the SWNTs. Our results show that, in the melt‐blended sample, the SWNTs—originally semiconducting—became predominantly metallic. The changes in the electronic properties were also confirmed by dielectric constant measurements. We propose that the anisotropic interaction between PMMA and SWNTs in the melt‐blended composite is the dominant reason for the observed electronic character change.