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Experimental Section General. Single-walled carbon nanotubes (SWNTs) were purchased from Carbon Nanotechnologies, Inc. (Houston, TX). D-(+)-Glucose, and glucose oxidase (GOx, EC 1.1.3.4, type X-S, lyophilized powder, 130~190 units/mg, from Aspergillus niger) were purchased from Sigma-Aldrich. Glucose stock solutions were mutarotated overnight at room temperature before use. All reagents and solvents were purchased from commercial suppliers and used as received. UV-Visible spectra were measured by using a Cary 50 UV-visible spectrophotometer. Ultrasonication was carried out in a Banson Ultrasonics B1510, and B2500 bath sonicator. Beckman Allegra [TM] X-22R Benchtop centrifuge was used for centrifugation. Raman spectra from all samples were collected with a Renishaw Ramanscope at an excitation laser wavelength of 785 nm. NMR spectra were measured on Bruker Avance 200 spectrometers. SEM was performed using a JEOL JSM-7000F scanning electron microscope. The Circular dichroism (CD) measurements were performed on an AVIV Circular Dichroism Spectrophotometer Model 410 (Biomedical Inc) at 25 °C. The samples were prepared from corresponding solid films dissolved in dilute acetic acid solutions in DI H 2 O (pH 4.5).

The interaction between single-walled carbon nanotubes and two anionic conjugated polyelectrolytes, poly[2,5-bis(3-sulfonatopropoxy)-1,4-phenylene-alt-1,4-phenylene) sodium salt and poly[2,5-bis(3sulfonatopropoxy)-1,4-ethynylphenylene-alt-1,4-ethynylphenylene] sodium salt, was investigated. It was found that the supramolecular polymer-nanotube assembly occurred efficiently and produced stable complexes that could be purified from excess free polymer in solution. These complexes were characterized using absorption spectroscopy, fluorescence spectroscopy, Raman spectroscopy, and electron microscopy. It was further found that patterning of these polymer-nanotube complexes could be accomplished by utilizing electrostatic attraction with a prepatterned, cationically charged surface. Patterned features were found to be electrically conducting with a measured sheet resistance value of 0.68 ( 0.01 MΩ for features having a thickness on the order of several nanometers.

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A fluoreneand azobenzene-containing conjugated polymer, poly[2,7-(9,9-didodecylfluorene)-alt-4,4′-azobenzene] (F12AZO) has been successfully synthesized using Suzuki polycondensation. The introduction of two dodecyl chains on the flourene unit resulted in a highly soluble polymer. F12AZO possesses excellent thermal stability, with a decomposition temperature over 400 °C under Ar. The reversible photoisomerization of the azobenzene units was achieved upon alternating photoirradiation with light of wavelength less than 450 nm (cis-form), and light in the range of 450−600 nm (trans-form). The supramolecular complex formation of trans-F12AZO, and cis-F12AZO with single-walled carbon nanotubes (SWNTs) has been studied, and it was found that this polymer can form very strong supramolecular polymer-nanotube assemblies. Furthermore, the trans and cis isomers of F12AZO enable the selective dispersal of individual SWNTs in toluene or THF, and the selectivity of the SWNTs is strongly dependent on the solvent, as well as the type of isomer used. UV−vis−NIR, and photoluminescence−excitation spectroscopy (PLE) were used for the characterization and identification of the nanotube species that are solubilized and exfoliated by this polymer.

A conjugated tertiary amine-functionalized polymer, poly(9,9-bis(diethylaminopropyl)-2,7-fluoreneco-1,4-phenylene), was synthesized and employed in the supramolecular functionalization of singlewalled carbon nanotubes. The formation of stable solutions in organic solvents, as well as in water upon protonation of the amine groups, indicates strong supramolecular interactions between the polymers and the carbon nanotube surface. UV-vis absorption spectroscopy and Raman spectroscopy were utilized to characterize the resulting functionalized nanotubes and it was found that the nanotube structure was unchanged due to the nature of noncovalent functionalization, thus preserving the nanotube's inherent properties. Electrophoretic deposition techniques were developed to create uniform films of this polymer and also a mixture of the polymer with the supramolecularly functionalized carbon nanotubes. The deposition mechanism involves the electrophoresis of the charged polymer species in an acid solution followed by the charge neutralization of the polymer species at the high pH region of the cathode surface. Scanning electron microscopy was used to visualize cross sections of the films as well as the film surfaces, showing uniform coatings that are free of cracks but contain small pores having diameters below 100 nm. The deposition rate was measured using a quartz crystal microbalance and found to vary with voltage and solution concentration. Control over film thickness was demonstrated in the range of approximately 100 nm to 10 μm.

The synthesis and fractionation of poly[2,7-(9,9-dioctylfluorene)-alt-2,5-(3-dodecylthiophene)] resulted in the isolation of eight different molecular weight (M w ) samples ranging from M n of 5 to 85 kg mol À1 . These individual polymer samples were fully characterized by Gel Permeation Chromatography, Nuclear Magnetic Resonance, as well as absorption and fluorescence spectroscopy. Each sample was separately mixed and ultrasonicated with single-walled carbon nanotubes (SWNTs) in tetrahydrofuran, and the nanotube concentration within the resulting solutions was measured. It was found that the solubility of the polymer-SWNT complexes strongly depends on the M w of the conjugated polymer, with a maximum concentration reached when M w ranged between 10 and 35 kg mol À1 . Higher and lower M w s resulted in substantially reduced nanotube concentrations.

H NMR spectra of the monomers 4, 8, and 9, 2D COSY, HSQC, HMBC spectra of PF-DTP1, and Raman spectra; tables of the relative content of the identified nanotube species from the PLE maps. This material is available free of charge via the Internet at http://pubs.acs.org.