Samarajeewa, D. R.Dieckmann, Gregg R.Nielsen, Steven O.Musselman, Inga H.2014-03-142014-03-142012-05-252012-05-252040-3364http://hdl.handle.net/10735.1/3159The electronic properties of carbon nanotubes can be altered significantly by modifying the nanotube surface. In this study, single-walled carbon nanotubes (SWCNTs) were functionalized noncovalently using designed surfactant peptides, and the resultant SWCNT electronic properties were investigated. These peptides have a common amino acid sequence of X(Valine) 5(Lysine) 2, where X indicates an aromatic amino acid containing either an electron-donating or electron-withdrawing functional group (i.e. p-amino-phenylalanine or p-cyano-phenylalanine). Circular dichroism spectra showed that the surfactant peptides primarily have random coil structures in an aqueous medium, both alone and in the presence of SWCNTs, simplifying analysis of the peptide/SWCNT interaction. The ability of the surfactant peptides to disperse individual SWCNTs in solution was verified using atomic force microscopy and ultraviolet-visible-near-infrared spectroscopy. The electronic properties of the surfactant peptide/SWCNT composites were examined using the observed nanotube Raman tangential band shifts and the observed additional features near the Fermi level in the scanning tunneling spectroscopy dI/dV spectra. The results revealed that SWCNTs functionalized with surfactant peptides containing electron-donor or electron-acceptor functional groups showed n-doped or p-doped altered electronic properties, respectively. This work unveils a facile and versatile approach to modify the intrinsic electronic properties of SWCNTs using a simple peptide structure, which is easily adaptable to obtain peptide/SWCNT composites for the design of tunable nanoscale electronic devices.©2012 The Royal Society of Chemistry Not to be further made available or distributed.NanoscienceNanotechnologyMaterials scienceNanotubes, CarbonCircular dichroismPeptidesTextSamarajeewa, D. R., G. R. Dieckmann, S. O. Nielsen, and I. H. Musselman. 2012. "Modifying the electronic properties of single-walled carbon nanotubes using designed surfactant peptides." Nanoscale 4(15): 4544-4554.4154544