Rational Chemical Strategies for Carbon Nanotube Functionalization

Abstract

Whereas the chemistry of fullerenes is well-established, the chemistry of single-walled carbon nanotubes (SWNTs) is a relatively unexplored field of research. Investigations into the bonding of moieties onto SWNTs are important because they provide fundamental structural insight into how nanoscale interactions occur. Hence, understanding SWNT chemistry becomes critical to rational, predictive manipulation of their properties. Among the strategies discussed include molecular metal complexation with SWNTs to control site-selective chemistry in these systems. In particular, work has been performed with Vaska's and Wilkinson's complexes to create functionalized adducts. Functionalization should offer a relatively simple means of tube solubilization and bundle exfoliation, and also allows for tubes to be utilized as recoverable catalyst supports. Solubilization of oxidized SWNTs has also been achieved through derivatization by using a functionalized organic crown ether. The resultant adduct yielded concentrations of dissolved nanotubes on the order of 1 g L(-1) in water and at elevated concentrations in a range of organic solvents, traditionally poor for SWNT manipulation. To further demonstrate chemical processability of SWNTs, we have subjected them to ozonolysis, followed by treatment with various independent reagents, to rationally generate a higher proportion of oxygenated functional groups on the nanotube surface. This protocol has been found to purify nanotubes. More importantly, the reaction sequence has been found to ozonize the sidewalls of these nanotubes. Finally, SWNTs have also been chemically modified with quantum dots and oxide nanocrystals. A composite heterostructure consisting of nanotubes joined to nanocrystals offers a unique opportunity to obtain desired physical, electronic, and chemical properties by adjusting synthetic conditions to tailor the size and structure of the individual sub-components, with implications for self-assembly.

One‐Dimensional Assemblies of Nanoparticles: Preparation, Properties, and Promise

“…In general, the preparation methods can be classified into three types: the first is direct chemical or physical vapor deposition of metal or semiconductor NPs onto the surfaces of the CNTs and NWs, [53] the second is sol±gel decoration of metal complexes onto the surfaces of CNTs and NWs, [54,55] and the last one is the modification of the surface properties of CNTs and NWs followed by specific adsorption of NPs. [56] Using the above strategies, many 1D arrays of varying types of metal and semiconductor NPs such as Au, [57±59] Ag, [60] Pt, [61,62] Cu, [63] Rh, [64] Sn, [65] Pd, [65] SnO 2 , [54] TiO 2 , [66] CdSe, [59,67,68] and CdTe, [69,70] have been formed. Herein, one example [71] is illustrated to demonstrate the preparation of 1D NP arrays using linear CNT templates (Fig.…”

Reactive Polymers: A Versatile Toolbox for the Immobilization of Functional Molecules on TiO2 Nanoparticles

“…[1] To have control of the inorganic nanoparticle surfaces allows one to tailor the particle size [2] and solubility. [3] Moreover, the surface characteristics of nanomaterials influence the broad range of properties and the performance of a large variety of devices.…”

“…The resulting polymer thus incorporates three different features: 1) a fluorescent dye as a functional demonstrator molecule, 2) 3-hydroxytyramine as anchor groups for attachment onto the metal oxide nanoparticles, and 3) a long alkyl chain to increase solubility in nonpolar solvents. The multifunctional polymers thus obtained were analyzed by 1 H NMR and FTIR spectroscopy and GPC to determine the composition of the polymers. The amount of dye and 3-hydroxytyramine, respectively, within the polymers P1, P2, and P3 was determined as 10 mol % each.…”

Materials directed to implants for repairing Central Nervous System

“…This provides the material with a high charge storage capacity through the double layer mechanism. The main disadvantage of these types of materials is the cytotoxicity, however, chemical modifications has been developed to improve their biocompatibility (63).…”