Selective polycarboxylation of semiconducting single-walled carbon nanotubes by reductive sidewall functionalization.
The efficient and controllable synthesis, the detailed characterization, and the chemical postfunctionalization of polycarboxylated single-walled carbon nanotubes SWCNT(COOH)(n) are reported. This innovative covalent sidewall functionalization method is characterized by (a) the preservation of the integrity of the entire σ-framework of SWCNTs; (b) the possibility of achieving very high degrees of addition; (c) control of the functionalization degrees by the variation of the reaction conditions (reaction time, ultrasonic treatment, pressure); (d) the identification of conditions for the selective functionalization of semiconducting carbon nanotubes, leaving unfunctionalized metallic tubes behind; (e) the proof that the introduced carboxylic acid functionalities can serve as versatile anchor points for the coupling to functional molecules; and (f) the application of a subsequent thermal degradation step of the functionalized semiconducting tubes leaving behind intact metallic SWCNTs. Functional derivatives have been characterized in detail by means of Raman, UV-vis/nIR, IR, and fluorescence spectroscopy as well as by thermogravimetric analysis combined with mass spectrometry, atomic force microscopy, and zeta-potential measurements.
Department of Chemistry and Pharmacy & Institute of Advanced Materials and Processes (ZMP), University of Erlangen-Nuremberg, Henkestrasse 42, 91054 Erlangen, Germany.
Benjamin
B
Gebhardt
Ferdinand
F
Hof
Claudia
C
Backes
Matthias
M
Müller
Thomas
T
Plocke
Janina
J
Maultzsch
Christian
C
Thomsen
Frank
F
Hauke
Andreas
A
Hirsch
D002264:Carboxylic Acids / Q000737:chemistry*; D004553:Electric Conductivity; D036103:Nanotechnology / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D013057:Spectrum Analysis
D002264:Carboxylic Acids; D037742:Nanotubes, Carbon